Biomass Integration With Landfill

1. Executive Summary

Acknowledgements

1.

Executive Summary

1

2.

Background to the Project

6

3.

Methodology

10

4.

Work Package 1 - Composting as Part of an Integrated Waste-to-Biofuel Programme.

11

4.1

4.2.

5.

Composting Industry in the UK

11

4.1.1.

Introduction

11

4.1.2.

Legislative Drivers

11

4.1.3.

Legislative Hurdles

13

4.1.4

Feedstocks

13

4.1.4.1.Green Waste

13

4.1.4.2.Source Separated

13

4.1.4.3.Municipal Solid Waste (MSW)

14

4.1.5.

Composting Methods and Technologies

14

4.1.6.

Compost Standards

15

4.1.7.

Conclusions with Respect to Composting in the UK

15

Composting and Short Rotation Coppice

16

4.2.1.

Introduction

16

4.2.2.

SRC and Landfill sites

17

4.2.3.

SRC and the treatment of leachate

18

4.2.4.

Other uses for compost

18

4.2.5.

Composting and Anaerobic Digestion

19

4.2.6.

Conclusions with Respect to Composting and SRC

19

Work Package 2: Potential for Growing SRC at Landfill Sites

20

5.1.

Introduction to SRC

20

5.2.

Site Selection

21

5.3.

Plantation Design

22

5.4.

Plantation Establishment

23

5.5.

Establishment Costs

24

5.6.

Support

25

5.7.

Bioremediation

25

5.8.

Potential Production of SRC from Greengairs and Riggend Sites

26

1. Executive Summary

6.

Work Package 3: Integration of Wood Fuelled CHP at a Landfill Site 6.1.

Wood Fuelled CHP

28

6.1.1.

28

Process Overview

6.2.

Wood Fuel Supply Strategy

29

6.3.

Markets for Wood Fuelled CHP

29

6.4.

Project Economic Evaluation

30

6.4.1.

31

6.5.

6.6.

7.

28

Project Concept Economic Model

Conceptual Systems Analysed

31

6.5.1.

Large Scale-High Conversion Scenario

31

6.5.2.

Large Scale-Low Conversion Scenario

32

6.5.3.

Small Scale-High Conversion Scenario

33

6.5.4.

Small Scale-Low Conversion Scenario

34

Discussion of Results

Demonstration Project

35

37

7.1.

Project Justification

37

7.2.

Project Implementation and Operating Timeframe

38

8.

Conclusions and Recommendations

40

9.

Further Research Work to take the Concept Forward

43

10.

Project Dissemination

44

11.

Limitation of Liability

45

12.

Project Management

46

Appendix A: Notes

47

Appendix B: References

49

1. Executive Summary

Acknowledgements This study was funded by shanks first fund. The project idea was conceived by Robert Brennan, Environmental Consultant and David Surplus, B9 Energy Biomass Ltd. The project team wishes to acknowledge their contributions in instigating this project. The project partners wish to acknowledge the following people for their valuable input and assistance during the project. •

R.W.Radley, EB Nationwide for his valuable input into the project.

•

G.McCabe and Shanks in general for their support and advice.

•

John Stewart, Scottish Environmental Protection Agency for advice and input.

1. Executive Summary

1. Executive Summary The concept behind this project, as illustrated below, is to produce compost from biodegradable municipal solid waste and use it to provide a growing medium for the production of short rotation coppice (SRC) willow on capped landfill areas and adjacent brown field sites. This SRC willow can then harvested and used as a renewable and sustainable energy source for the production of combined heat and power (CHP). This project creates a positive use for this waste fraction by supporting the incremental production of renewable energy from essentially unproductive ‘contaminated’ land. The concept is targeted directly at achieving the EU’s and UK’s goals of reducing biodegradable waste going to landfill and increasing renewable energy production to promote sustainability and mitigate against climate change. This desk top study, carried out by recognised experts from industry, government departments and universities, has shown that it is potentially feasible to use compost produced from sorted MSW to grow biomass for use as a sustainable and renewable energy supply for a CHP unit. The results of this study were applied to conditions prevailing at two landfill sites and used to identify where further research and development work was required. A strategy for taking the fully integrated concept forward was developed, involving an integrated cross-sectoral approach, between agriculture, energy and waste industries. It has been shown that there are clear economic, social and environmental, benefits that could be achieved while meeting the new and growing legislative requirements for dealing with wastes and increasing the use of renewable energy. Few people outside the waste management industry realise either the sheer scale of waste disposal, or the real cost of waste to society. Reducing and managing waste is central to sustainable development. Waste disposal and its environmental impact is a European wide issue and to ensure a level playing field many pieces of European Legislation (Directives) have been agreed or are under discussion. These new Directives will discourage the production of waste and call for a dramatic change in the way waste is dealt with. As most of the waste in the UK is currently disposed of at landfill sites, the Landfill Directive is a key policy driver. This will impose minimum environmental standards for landfill sites and set targets for reducing the amount of Biodegradable Municipal Waste (BMW) that is sent to landfills. These targets are driven by the fact that BMW decomposes anaerobically in landfill sites with the production of the colourless gas methane, which is 21 times more effective as a greenhouse gas than carbon dioxide. At some landfill sites the methane gas is collected and used to fuel engines to generate electrical power. Unfortunately at most sites this is not the case and the methane escapes to atmosphere. One third of the European methane emissions are generated by landfills and this is why the European Commission has targets for the reduction of BMW going to landfill. The UK Household waste arisings have been estimated by the DETR to be 27 million tonnes per year. The Environment Agency has estimated that 62% of this material is biodegradable. These figures indicate that to reduce the amount of BMW going to landfill by as little as a quarter is going to require a major re-orientation of the waste management industry. An unavoidable consequence of waste recycling and processing is an increase in energy usage compared to the landfilling of such waste. Therefore, in addition to responding to new Landfill Directives, the waste industry must also address issues relating to energy use and the corresponding greenhouse gas emissions. The UK has adopted the Climate Change Levy, as a tax on the use of fossil fuels. It is committed under the Kyoto Protocol to reducing greenhouse gas outputs by 12.5% below 1990 levels by 2010, while the EU as a whole is committed to a reduction of 8% by the same date. The UK Government has gone further in that it has a domestic goal to reduce carbon dioxide emissions by 20% below 1990 levels by 2010. It has also made a further commitment that 10% of electricity will be provided from renewable sources by 2010. In order to meet the above target the renewable energy sector will have to grow by a factor of seven. At the present time, the composting industry of the UK is in a time of great change. The general trend is one of growth and diversification, and there is potential for composting to become a significant part of an integrated and sustainable waste management strategy for the future. There are a number of policies and directives that are driving the expansion of the composting industry in the UK. As well as the Landfill Directive the UK currently applies a landfill tax of £12 to each tonne of material that is landfilled, and this charge is set to rise annually by at least £1 for the foreseeable future. The Draft Biowaste Directive states that the UK must set up separate collection schemes with aim of collecting biowaste separately from other kinds of waste. Under existing collection schemes 46,000 tonnes of source separated organic waste was collected in the UK in 1999. In mainland Europe composting of source separated organic waste has proven itself as a valid method of improving recycling rates. The Draft Biowaste Directive also calls on the public sector to use compost as a substitute for peat wherever possible. “Peatering Out” is a ten year plan for the phasing out of peat from the UK, recently published by the RSPB and English Nature. Replacing this material with renewably sourced products could provide a significant ‘pull through’ effect to stimulate the composting industry.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 1

1. Executive Summary

In the UK there are significant legislative hurdles to the expansion of the composting industry. The Animal By-products Order was introduced by DEFRA (then DETR) in 1999 in the wake of the BSE crisis, and was aimed at improving food safety practises in the UK. This legislation effectively eliminates any end use markets and has impeded the growth of the industry. Continued enforcement of the amendment will seriously threaten the UK’s chances of meeting the targets set out in the Landfill Directive. However, DEFRA have indicated that the legislation is likely change in the Spring / Summer of 2002. It is possible that composting food waste and the use of compost containing food waste will be allowed if an in-vessel system is employed and the waste fulfils time-temperature requirements designed to eliminate pathogens. Additionally, the Environment Agency requires most composting facilities to hold a Waste Management Licence. Applying for, receiving and meeting the conditions of Waste Management Licenses can be a time consuming and expensive business and the matter has recently been further complicated by the Environment Agency’s position on Bioaerosols. If the EA maintain their position, it may be an impossible task to find appropriate sites for the 380 additional composting facilities that the DETR estimate will be needed to meet the demands of the Landfill Directive. However, the overall picture for composting in the UK is one of continued expansion. Over the last five years the number of operational centralised composting facilities has grown, on average, by around 25% per annum, in 1999 there were 197 sites processing approximately 833,044 tonnes of material. Composting methods are many and varied. However, in broad terms, the available methods can be divided into two classes: open-windrow and in-vessel. In 1999, The Composting Association’s report identified 152 sites using an open-air composting method, and only 7 using in-vessel composting methods. Open-air and in-vessel composting each have their own advantages and disadvantages, in terms of capabilities, cost and environmental impact. In May 2000 The Composting Association introduced a set of standards for compost, which aim to encourage the manufacture of good quality compost and increase confidence in the product. Whilst these standards have been adopted as a recognised industry standard, participation in the scheme is voluntary. Elsewhere such standards have been built into the appropriate legislation and act as a driver in the development of new composting technologies and techniques. The Waste and Resources Action Programme (WRAP) has identified the need for comprehensive standards for compost products and is commissioning a comparison of International compost standards that will inform the development of enforceable standards here in the UK. A very cautious approach to planning and licensing has lead to the introduction of legislation that impedes other directives and, at present, this is constraining the development of the composting industry. A co-ordinated effort between industry and government has now begun to develop standards and protocols that are both practical and effective in providing assurances that composting is a safe and sensible method of recycling biodegradable wastes. These initiatives will probably result in large quantities of compost becoming available. One of the possible uses for such compost is as a primary resource for SRC production. SRC is an intensive management system which has been used on woody species principally willow (Salix) for basketry, hazel (Corylus) and sweet chestnut (Castanea). There are major difficulties in arriving at robust costs for establishing SRC willow in the United Kingdom. There are relatively few commercial areas of willow to provide actual costs and it has been shown that ‘pioneer’ growers of SRC will incur greater costs in all spheres of operation compared with growers where there is significant activity in the sector. Comparison of costs in Sweden where establishment costs are £700-900 ha-1 with those in the United Kingdom estimated at £1700-1900 ha-1 illustrates this point. Overall production costs, including plantation management and harvesting, are again at this stage difficult to estimate because of the lack of real data. However, based on a crop of 10t dry matter per hectare per year the average costs of growing SRC over a 25 year rotation (8 x 3 year harvests) can be estimated at £300 per hectare annually. These costs are obviously dependant on scale of operation, degree of mechanisation etc. and will also be influenced by crop yield. There are a number of schemes that support the establishment of SRC. The main vehicle currently is the Woodland Grant Scheme (WGS) and although supplementary aid through the Arable Area Aid Scheme is given on setaside land, grassland is only eligible for WGS support. There is a serious imbalance of support between grassland (non-setaside) sites and setaside sites. This has been addressed in the Rural Development Plan, which has been adopted for England, where the EU have approved an up-front payment of £1600 ha-1 for the establishment of SRC on grassland. The other UK regions have yet to finalise their support initiatives but there would be little agreement for significant variation from the English scheme. A detailed assessment was made of the potential to produce SRC from the Greengairs and Riggend landfill sites. On-site discussions indicated that within the site boundary all areas were potentially available for SRC production. In the proposed sites account will have to be taken of elevation, exposure, soil quality and compaction. For this reason realistic yield estimates for the ex-farmland will be 6-8 tonnes DM ha-1 yr-1 and on the landfill 4-6 tonnes DM ha-1 yr-1. These figures will be used in the calculations of the heat and power output from a biomass Combined Heat and Power (CHP) unit. CHP is the on-site generation and use of heat and electricity. In a CHP system a turbine or engine is connected to an alternator to produce electricity, while the engine jacket and exhaust heat is used to produce steam or hot water. The standard CHP

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 2

1. Executive Summary

technology uses fossil fuels, typically natural gas or diesel oil, to fire the turbine or engine. With the B9 Energy technology the engine is fired on a syngas produced by the gasification of biomass wood chips. Within this concept the CHP is fuelled from chipped SRC willow grown on the landfill sites, on nearby brown field sites and on agricultural land. However, the CHP unit may be fuelled by any combination of SRC, sawmill woodchips and forestry residues. Markets currently exist for the heat and electricity produced from renewable resources. Electricity can be transported over long distances without significant energy losses, which is not the case with heat networks. An SRC fuelled CHP unit is therefore best located as close as possible to a heat user. It should also be sited within reasonable proximity to the SRC source but not necessarily at a landfill site. There are Government incentives in place to promote the use of renewable energy including the Climate Change Levy and the Renewables Obligation (RO). The RO is an obligation placed on licensed Public Electricity Suppliers (PES) to supply a specified proportion of their electricity supplies to customers from renewable sources of energy. As an alternative to supplying renewable electricity, suppliers can buy out their obligation at a fixed price, likely to be 3 pence per kWh. There will be a number of additional opportunities arising from trading of “Green Certificates”, such as Renewables Obligation Certificates (ROCs) and Levy Exemption Certificates (LECs). To simplify the economic analysis it will be assumed that the landfill operator has selected the most appropriate feedstock treatment and compost production facility for his landfill site in order to comply with EC Directives. It is also assumed that the avoided landfill disposal costs and the avoided landfill tax will be used by the landfill site operator to finance the construction of the feedstock treatment and compost production facility. This will allow the compost to be made available at zero cost to a potential user. In order to evaluate the economic viability of the project concept an Excel® spreadsheet model was developed which is available via the B9 Energy website. This spreadsheet considers the capital costs, the operating and maintenance costs, the cost of any additional wood supplies that are required, and the income generated by the project from the sale of electricity and heat and from avoided leachate treatment and land remediation costs. The use of this economic model allows the projected income and expenditure to be analysed on an annual basis, which coupled to information on the capital costs, permits a profit and loss account, project paybacks, return on investment (ROI) and internal rates of return (IRR) to be calculated. Such criteria are well established as project investment decision tools. In the economic analysis two different sized landfill site case studies were analysed and for each site two different compost conversion rates were analysed. The assumptions behind these scenarios can be challenged and there is limited published quantitative research data on which to base any firm opinion. However, the systems analysed in this report are based on the best available information generated by the project partners. It will vary from site to site and each individual project must be evaluated on its own merits and real life operating and capital costs included for any specific project economic/financial appraisal. For the large-scale high conversion rate scenario 140,000 t/year of compost is produced and spread on the 48 hectares of the landfill site and an additional 470 hectares of brown field site. Over the 15 years of the project a total of 44,500 tonnes of SRC is produced, which together with 16,000 tonnes of additional off-site wood fuel is sufficient to supply a 750kWe CHP unit. The profit and loss account shows an average profit of £460,000/yr, which against a capital cost of £1M for the CHP unit and leachate recycle plant give a simple payback period of 2.2 years and a ROI of 45%. The cash flow situation is quite complicated in that the main revenue stream, the avoided remediation cost, is realised in the first three years. This gives a very positive cash flow situation for the first three years. However, for the remainder of the project the cash flow is negative because the leachate recycle, SRC production and off-site wood costs are higher than the income from the CHP unit. Emissions savings over the project lifetime are 90,000 tonnes CO2, 382,000 tonnes CH4, -93 tonnes NO2, 1,100 tonnes SOx. The savings generated from the reduction in CO2 emissions equate to 34 million litres of diesel. For the large-scale low conversion rate scenario a total of 52,000 t/year of compost is produced and spread on the 48 hectares of the landfill site and an additional 144 hectares of brown field site. Over the 15 years of the project a total of 15,800 tonnes of SRC is produced, which together with 8,500 tonnes of additional off-site wood fuel is sufficient to supply a 300kWe CHP unit. The average profit is £118,000/yr and the total capital cost for the CHP unit and leachate recycle plant is just under £0.5M, giving a simple payback period of 4.3 years and a ROI of 23.3%. Similar cash flows exist as for the previous scenario. Emissions savings over the project lifetime are 36,000 tonnes CO2, 142,000 tonnes CH4, -37 tonnes NO2, 440 tonnes SOx and the reduction in CO2 emissions equate to 13.5 million litres of diesel. For the small-scale high conversion rate scenario 51,000 t/year of compost is produced and spread on the 178 hectares of the landfill site and an additional 10 hectares of brownfield site. Over the 15 years of the project a total of 12,600 tonnes of SRC is produced, which together with 8,500 tonnes of additional off-site wood fuel is sufficient to supply a 260kWe CHP unit. The profit and loss account shows an average loss of £109,000/yr for the 15 years of the project. The total capital cost for the CHP unit and leachate recycle plant is just over £0.72M. This scenario is adversely affected by both the high operating cost

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 3

1. Executive Summary

(£292,000/yr) and capital cost (£356,000) of the leachate recycle system. For the small-scale low conversion rate scenario 21,000 t/year of compost is produced and spread on 77 hectares of the landfill site with no additional brownfield sites required. Over the 15 years of the project a total of 5,100 tonnes of SRC is produced, which together with 5,500 tonnes of additional off-site wood fuel is sufficient to supply a 130kWe CHP unit. A higher proportion of additional off-site wood is required for this scenario because this is the smallest size of CHP unit that can be specified. The profit and loss account shows an average loss of £54,000/yr for the 15 years of the project. The total capital cost for the CHP unit and leachate recycle plant is just under £0.4M. Again, this scenario is adversely affected by both the high operating cost and capital cost of the leachate recycle system. From the results presented above a clear picture emerges with regard to the economic viability of this concept. The important income generation streams are the avoided remediation costs and the sales of heat and electricity. The important expenditure streams are the leachate recycle system, the cost of producing the SRC and the cost of purchasing the additional off-site wood required. The total area that can be remediated depends directly on the compost available and therefore directly on the scale of the landfill site and the conversion rate of MSW and green waste to compost. The large scale site with a high conversion rate requires 518 hectares of land, whereas the small scale site with a low conversion rate requires only 77 hectares. The sales of electricity and heat depend on the size of the CHP unit. In these scenarios the CHP unit has been sized to use all of the SRC produced while minimising the amount of off-site wood purchased. However, the cost of SRC produced on the landfill site is £94.3/dry tonne, which is equivalent to 7.8p/kWh on the price of electricity. For brown field sites the figures are £70/dry tonne and 5.8/kWh and for off-site wood £40/dry tonne and 3.3pkWh. Therefore, on a case by case basis the size of CHP unit and quantity of off-site wood purchased should be reviewed in light of the availability of low cost off-site wood. Increasing the size of the CHP plant will have a small positive effect on the project viability. Although SRC as a fuel is more expensive than purchasing wood from off-site sources it should not be forgotten that SRC is the catalyst for the system, and provides the outlet for the compost in the form of a growing medium. The value attached to the SRC is not an economic one related to its production cost but is as a medium via which waste derived compost can be used. A significant impact on the viability of the small scale systems is the leachate recycle system. While there is a saving in leachate treatment costs this is substantially less than the consumables and manpower costs involved with operating the leachate recycle system. The volume of leachate that is recycled depends on the area of the landfill site, and therefore the small scale site which has a large landfill area suffers the most from this. An additional income, in the form of a fee for using the compost, would have a large positive impact on all of these scenarios. In particular for the small scale scenarios a pay back period of less than 5 years is possible if a fee of £5-£7/tonne of compost used was available. The potential waste diversion rates and savings in emissions demonstrate that the project concept could have a key role to play in future waste management strategies and in meeting global emission reduction targets. A successful project would also help to improve the image of landfill sites and by implication improve the public perception of landfill companies. Successful project delivery will depend on the developers putting in place the necessary information to demonstrate that the project will meet the financial/economic, environmental, legislative and regulatory criteria required by the various responsible entities. As with all such projects early attention to PR and consultation with local communities, planners and other regulatory bodies is vital to ensure a broad-based understanding and successful project implementation. In terms of project management a crosssectoral approach is required, including expertise from agriculture, waste and energy sectors. A practical demonstration of the concepts would be the focus of great interest for both landfill operators and the wider environmental community. The project concept results in increased employment opportunities arising from various construction activities, from the establishment, production and harvesting of SRC fuel and from the operation of the composting and CHP facilities. The provision of these facilities will also result in a multiplier effect on the local economy. Rural regeneration could be assisted by diversification of agriculture into energy crops and local farmers and contractors already possess the skills and equipment required. Selected public access could be given to completed areas of the site and the development of such schemes with local groups could give the community some sense of “ownership”. The integration of wood fuelled CHP with SRC plantations and composting facilities at a landfill site is an example of good practice in sustainability. Such a project would form a virtuous circle and would demonstrate how the practical application of sound environmental principles can be both economically viable and meet EU and UK targets on sustainability, renewable energy and waste reduction. The following areas should be researched prior to commercialising the concept: The suitability of waste derived compost for returning organic matter to soil. The potential to use waste derived compost for the establishment of new stands of SRC.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 4

1. Executive Summary

The effect of the project concept on reducing methane emissions. The potential to provide a continuous outlet for compost in top dressing SRC. The potential application of leachate to SRC. The integration of an SRC fuelled CHP unit with a landfill site. The impact on landfill operating costs and overheads. A pilot project is needed in order to provide the facilities on which to carry out an overall mass balance of the system, and help further research detailed above. An integrated project based on this concept would be the first project of its kind in the World and would demonstrate: •

Composting waste to form a growing medium.

•

Growing SRC in compost on top of the landfill cap

•

Reapplying compost for weed control.

•

Use of leachate to improve crop yield.

•

A biomass CHP unit fuelled by SRC grown on the land fill site and surrounding area.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 5

2. Background to the project

2. Background to the project This project concept was originally conceived by David Surplus of B9 Energy and Robert Brennan, an Environmental Consultant. Previous research had led them to believe that renewable energy had a productive and increasing role to play in the waste management industry. A number of other partners participated in the project: Shanks with respect to their Lanarkshire Greengairs landfill site operation, the Department of Agriculture and Rural Development for Northern Ireland for SRC willow, RSL for composting and B9 Energy Biomass for Combined Heat and Power (CHP) technology and project management. The project takes a holistic approach with regard to the factors affecting waste disposal, with the intention of assessing the benefits arising from introducing fast growing willow as an energy crop at a landfill site, which would then be used in a high efficiency CHP unit. The following picture provides a visual representation of the concept.

The project carried out a desk top study into the technical, environmental and economic implications of introducing composting, energy crop production and biomass conversion technology into a landfill operation. A landfill site is defined as a brown field site [Ref 1] or a contaminated land site and its land use is clearly defined and strictly limited. As such when sites are closed they represent an ongoing liability to the operator through site restoration and maintenance. This project explored the potential of turning these sites into assets by producing energy crops, which when burned produce revenue streams from the sale of renewable heat and power. The project is best summarised by comparing the two figures below, which illustrate a typical landfill site (Figure 1) and the potential effect of introducing this project concept (Figure 2).

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 6

2. Background to the project

Figure 1: Current Situation at a typcal Landfill Site

Figure 2: Future Scenario at a typcal Landfill Site

In Figure 1. the MSW is landfilled and produces landfill gas, which is either released to atmosphere, flared or used for energy generation. Leachate is also produced and treated at the site. In Figure 2. pretreated MSW is diverted to a composting facility. The compost produced is blended with soil and spread on the cap of the landfill site as a growing medium for SRC. To optimise the growth of the energy crop, dressing the site with compost is considered both to avoid the willow root system from penetrating the site cap, and just as importantly to provide a nutrient base and fluid retention for the willow. Additionally the use of leachate as a nutrient is considered. The use of compost is significant as this can be made from the biodegradable waste fraction of household waste. This fraction of waste comes under specific attention of the Landfill Directive [Note 1, Ref 2], which ultimately seeks to ban this from landfill. SRC is harvested to fuel a CHP unit that provides renewable electricity and heat.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 7

2. Background to the project

“A key priority of government is to de-couple economic growth from increases in waste arising (quantity of waste); we must stop viewing wastes as a by-product of consumption and treat it as a resource to which value can be added through sophisticated technologies” as stated by Michael Meacher Minister of State for the Environment. Few people outside the waste management industry realise either the sheer scale of waste disposal, or the real cost of waste to society. Reducing and managing waste is central to sustainable development. Waste disposal and its environmental impact is a European wide issue and to ensure a level playing field many pieces of European Legislation (Directives) have been agreed or are under discussion. These new Directives will discourage the production of waste and call for a dramatic change in the way waste is dealt with. As most of the waste in the UK is currently disposed of at landfill sites, the Landfill Directive is a key policy driver. This will impose minimum environmental standards for landfill sites across Europe and most importantly will ban the landfilling of many materials. The Directive calls for a progressive reduction in biodegradable municipal waste (BMW), such as garden waste, kitchen scraps and newspapers. These wastes decompose anaerobically when landfilled with the production of methane gas, which is both explosive and contributes to global warming. At some landfill sites the gas from this decomposition is collected and used to fuel engines that generate electrical power. Unfortunately at most sites this is not the case and the methane escapes to atmosphere. Landfill sites generate one third of European methane emissions and this is why the European Commission has targets for the reduction of biodegradable municipal waste going to landfill. Reductions in biodegradable waste going to landfill must be achieved by 2010, with further incremental reductions required by 2013 and 2020. Two implications are apparent, firstly increasing quantities of waste must be recovered and ‘processed’, and secondly, energy use per ton of waste ‘processed’ will increase substantially compared to the landfilling of such waste. Therefore, in addition to responding to new Environmental Legislation, the waste industry must also address issues relating to energy use and the corresponding greenhouse gas emissions. The UK has adopted fiscal policy, as represented by the Climate Change Levy, which is a tax on the use of (fossil fuel) energy. It is committed under the Kyoto Protocol to reducing greenhouse gas outputs by 12.5% below 1990 levels by 2010, while the EU as a whole is committed to a reduction of 8% by the same date. The UK Government has gone further in that it has a domestic goal to reduce carbon dioxide emissions by 20% below 1990 levels by 2010 [Note 3, Ref 3]. It has also made a further commitment that 10% of electricity will be provided from renewable sources by 2010. An interim target has been set to achieve 5% of electricity to be provided by renewables by 2003 [Ref 4]. In order to meet the above target the renewable energy sector will have to grow by a factor of seven. The waste management industry is faced with two conflicting issues. It must comply with waste legislation, which will increase the need to implement recycling facilities and therefore increase energy usage. At the same time the industry must contribute to government policy and reduce emissions from energy usage. This project seeks to address how the industry can mitigate the increase in (fossil fuel) energy consumption that will be required by the industry as the ‘treatment’ of waste rises in lieu of direct disposal to landfill. This project seeks to assess the possibilities of producing renewable energy using the industry’s current primary asset, landfill. In order to appreciate the practical issues involved at a landfill site the project was kindly granted permission for access to a large operational landfill site in Lanarkshire, Central Scotland. The following figures are provided to represent the situation in Scotland, but the same principles apply throughout the UK and such figures are/should be available from the relevant local Environmental Agency. These figures were obtained from SEPA, Scottish Environment Protection Agency. Waste is classified under a number of categories as illustrated in Figure 3 below. Figure 3: Classification of Waste to Landfill

Household waste 3.0 Manufacturing/Other 1.8 Commercial 2.0 Construction & Demolition 5.1

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 8

2. Background to the project

In 1998 some 12 Million tonnes of waste was landfilled in Scotland as follows: Millions of tonnes Household waste Construction & Demolition Commercial Manufacturing/other

3.0 5.1 2.0 1.8

Waste is growing on average at circa 2% per year [Note 4]. This waste is landfilled in the 263 landfill sites currently licensed by the Scottish Environmental Protection Agency (SEPA) to operate in Scotland. These sites vary considerably in size from small rural sites to large fully engineered sites. The most significant are the 13 sites licensed to take in excess of 150,000 tonnes per annum. The EU Landfill directive referred to earlier will impact on household waste, of which some 60% is classified as BMW, (biodegradable municipal waste). The collection and disposal of household waste is a statutory requirement of Local Authorities. Some Local Authorities organise waste collection and have their own landfill sites, whilst others contract out their requirements to the private sector waste management industry To comply with the legislative framework a National Waste Strategy [Ref 5] has been drawn up. This is being co-ordinated at a local level by, for example, in Scotland eleven Waste Strategy Area Groups. One such group is Glasgow and Clyde Valley containing eight Local Authorities. The EU Landfill Directive Targets for this group are as follows [Figure 4]. BMW diversion required by 2010 = 312,000 tonnes/annum BMW diversion required by 2013 = 495,000 tonnes/annum BMW diversion required by 2020 = 679,000 tonnes/annum (The Directive defined the base line year as 1995, and in that year 576,000 tonnes of BMW was landfilled. The targets assume a 2% annual increase in waste production from 1995 [Note 4]). BMW TARGETS IN TONNE

800000 600000 400000 200000 0

Current Diversion

by 2010

by 2013

by 2020

TONNES

Figure 4: BMW Diversion Targets The targets for this area seek to illustrate the scale of the challenge across the UK. The question arises as to what to do with this substantial tonnage of BMW. This project suggests a positive use for this waste fraction in supporting the incremental production of renewable energy from essentially unproductive ‘contaminated’ land. A critical mass of energy crop needs to be made available in order to justify/optimise investment in the project. Therefore, it is worth considering that the principle of the project could apply to many brownfield or contaminated sites, as well as landfill, within a given area.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 9

3. Methodology

3. Methodology An inaugural meeting was held to develop the initial concepts of the project. This led to the establishment of a number of tasks that were broken down into work packages corresponding to the competencies of the partners: •

Workpackage 1: Composting as part of an integrated waste-to-biofuel programme. (RSL)

•

Workpackage 2: Potential for growing SRC at landfill site (DARD)

•

Workpackage 3: Integration of wood fuelled CHP at landfill site (B9 Energy)

The overall management of the project was carried out by B9 Energy Biomass Ltd and R Brennan. A number of progress meetings were held to review progress towards completion of the tasks. Details of the completed tasks were published as interim reports within the project team and to EB Nationwide. B9 Energy Biomass fulfilled the editorial function in compiling the interim and final reports as well as the administration and financial control of the project.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 10

4. Work Package One

4. Work Package 1 Composting as Part of an Integrated Waste-to-Biofuel Programme.

4.1. Composting Industry in the UK 4.1.1.Introduction Compost can be defined as biodegradable waste that has been aerobically processed to form a stable, granular material containing valuable organic matter and plant nutrients which, when applied to land, can improve the soil structure, enrich the nutrient content of soil and enhance its biological activity. The biological processes involved in the creation of compost are entirely natural, and are essentially the same in all composting operations, from domestic compost heaps to large and technologically advanced operations that are capable of composting 50,000 tonnes of waste per year. However, the practical implications of composting vary greatly, depending on a variety of issues including the type and volume of waste, the processing technique employed, prevailing weather conditions, the required end use of the compost and the relevant legislation. Householders across the UK are already composting many millions of tonnes of their hedge prunings, grass cuttings and kitchen waste in their own back gardens. The Composting Industry (i.e. centralised composting facilities), and the factors affecting its growth, planning, licensing and operation is the main subject of this section. At the present time, the composting industry of the UK is in a period of great change. The general trend is one of growth and diversification, and there is potential for composting to become a significant part of an integrated and sustainable waste management strategy for the future.

4.1.2. Legislative Drivers There are a number of policies and directives that are driving the expansion of the composting industry in the UK over the coming years. Currently a landfill tax of £12 is applied to each tonne of material that is landfilled in the UK and this charge is set to rise annually by at least £1 for the foreseeable future. This tax increase, coupled with an exhaustion of suitable landfill sites, is likely to make landfill an increasing expensive waste disposal option. These cost increases will make many types of recycling more financially attractive to waste producers and disposal authorities, and composting is no exception. In some areas of mainland Europe, where the price of landfilling is considerably higher, recycling and composting has been financially competitive for over 10 years and recycling rates far exceed those achieved in the UK.

The Landfill Directive [Note 1 Ref 2] was introduced by the European Commission (EC) in 1999 and sets requirements for reducing the amount of Biodegradable Municipal Waste (BMW) that is sent to landfills. The Directive requires that: • • •

By 2010 BMW landfilled be reduce to 75% of that in 1995 By 2013 BMW landfilled be reduced to 50% of that in 1995 By 2020 BMW landfilled be reduced to 35% of that in 1995.

These targets may seem demanding and it may seem puzzling that the EC has chosen to focus on a waste stream that will independently decompose in any landfill. Indeed, plastic waste within a landfill will persist for many more years than biodegradable material, but the scientific reasoning behind the legislation is powerful. If biodegradable waste, such as kitchen scraps and newspapers, is buried in a landfill, it will decompose anaerobically (without oxygen). This anaerobic decomposition results in production of the colourless gas methane, which is both explosive and a contributor to global warming. In fact, methane is 21 times more effective as a greenhouse gas than carbon dioxide [Note 2]. A third of the European methane emissions are generated by landfills and this is why the EC has targeted BMW and seeks to reduce its contribution to climate change. The UK Household waste arisings have been estimated by the DETR to be 27 million tonnes per year [Ref 6]. The Environment Agency has estimated that 62% of this material is biodegradable. These figures indicate that to reduce the amount of biodegradable material going to landfill by as little as a quarter is going to

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 11

4. Work Package One

require a major re-orientation of the waste management industry. The Composting Association [Ref 7] has estimated exactly how much BMW will have to be diverted from landfill and treated with other waste management techniques such as composting, in order to meet the Landfill Directive’s targets.

Year

Total biodegradable municipal waste to be diverted from landfill (million tonnes per annum)

Organic fraction (garden and kitchen waste) to be diverted from landfill (million tonnes per annum)

2010 2013 2020

12.4 – 15.5 18.5 – 21.9 26.8 – 31.0

4.9 – 7.7 7.3 – 10.9 10.6 – 15.5

Table 1. The Composting Association estimates for meeting EU Landfill Directive The Draft Biowaste Directive [Ref 8], introduced in 2001 by the EC, states that the UK must “set up separate collection schemes with aim of collecting biowaste separately from other kinds of waste… in particular, food waste from private households…. from restaurants, canteens, schools and public buildings… biowaste from markets… from shops… from commercial, industrial and institutional sources… and green and wood waste from private as well as public parks, gardens and cemeteries”. The Directive also states “These separate collection schemes shall at least cover: •

Urban agglomerations of more than 100,000 inhabitants within three years:

•

Urban agglomerations of more than 2,000 inhabitants within five years”.

The Composting Association [Ref 7] has found that under existing collection schemes 46,000 tonnes of source separated organic waste was collected in the UK in 1999, 21,000 tonnes of which was mixed garden and kitchen waste. This was collected via 37 schemes operated by waste collection authorities. A further 63 waste collection authorities plan to start sources separated organic waste collection schemes, indicating that just under two-thirds of all UK waste collection authorities intend to improve their recycling targets by asking householders to separate waste for composting. Many European countries are already separately collecting the compostible fraction of household waste. As long ago as 1997 some 2,000,000 tonnes of source separated organic waste was composted each year in Germany [Ref 9], representing nearly a quarter of their estimated quantity of recoverable organic waste. It’s clear that in mainland Europe, composting of source separated organic waste has proven itself as a valid method of improving recycling rates. “Peatering Out” [Ref 10] is a ten year plan for the phasing out of peat from the UK, recently published by the RSPB and English Nature. It reports that 96% of growing media in the UK is currently peat based and total horticultural peat usage is calculated to be over 3.5million cubic meters per annum. This peat is mined from lowland raised bogs, one of the UK’s rarest habitats, 94% of which has already been lost. Between 50-60% of UK peat production is located on sites proposed as Special Areas of Conservation, meeting the European Union’s criteria for international environmental importance. Replacing this material with renewably sourced products such as recycled organic wastes could provide a significant ‘pull through’ effect to stimulate the composting industry. The Draft Biowaste Directive [Ref 8] states “Public authorities and the public sector shall use compost as a substitute for peat and other raw material extracted from the environment wherever possible” and indeed, there appears to be a growing movement away from the use of peat as a horticultural product. In 1999 the members of the National Trust voted overwhelmingly to phase out the use of peat in all Trust gardens. They undertook trials to examine the use of alternatives and the encouraging results were reported in the trust’s magazine [Ref 11]. The trials were so successful that the National Trust has launched their own range of peat free products based on wood-waste, at a price of £4.50 for a 40 litre bag, which is equivalent to a cost of £112.50 per cubic meter. The National Trust is not the only organisation moving in this direction. B&Q, the largest UK retailer of peat, announced a new policy in April 2001 that aims for peat alternatives to provide 85% by volume of all growing media and soil improvers by the end of 2006. The Great Mills DIY chain have a green compost/low peat

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 12

4. Work Package One

multipurpose compost, Terra Ecosystems have a retail range based on composted sewage sludge, and Sinclair Horticulture and Gem both have peat free ranges.

4.1.3. Legislative Hurdles The Animal By-products Order [Ref 12] was introduced by DEFRA (then DETR) in 1999 in the wake of the BSE crisis, and was aimed at improving food safety practises in the UK. In June 2001, following the Foot and Mouth outbreak, an amendment to the order has prevented the use of compost containing any food waste (domestic or commercial). Such compost may currently not be put to land where animals (including wild birds) have access to it, but should be sent for disposal at landfill sites. This legislation effectively eliminates any end use markets and has impeded the growth of the industry and presented significant problems for the waste collection and disposal authorities that are currently planning, running, and expanding household collections of biowaste. Continued enforcement of the amendment will seriously threaten the UK’s chances of meeting the targets set out in the EC Landfill Directive. However, DEFRA have indicated that the legislation is likely change in the Spring / Summer of 2002. It is possible that composting food waste and the use of compost containing food waste will be allowed if an invessel system is employed and the waste fulfils time-temperature requirements designed to eliminate pathogens. The Environment Agency is now encouraging the use of enclosed or ‘in-vessel’ systems as the preferred approach for large scale composting facilities where odours or bioaerosols may be an issue. The Environment Agency requires most composting facilities to hold a Waste Management Licence [Ref 13]. Applying for, receiving and meeting the conditions of Waste Management Licenses can be a time consuming and expensive business and the matter has recently been further complicated by the Environment Agency’s position on Bioaerosols [Ref 13]. These are air borne micro-organisms that have the potential to produce health effects in humans. There is still much to be learnt about bioaerosols, their generation and methods of detection and control. However, because of the potential risk to health, the Environment Agency will not license, and will object to planning applications for, composting facilities “where the boundary of the facility is within 250 meters of a workplace or the boundary of a dwelling, unless the application is accompanied by a site-specific risk assessment, based on clear, independent scientific evidence which shows that the bioaerosol levels are and can be maintained at appropriate levels at the dwelling or workplace”. Bearing in mind there is not yet a widely established method of testing bioaerosol levels, and no consensus on what constitutes an “appropriate level”, this will be a difficult task for the majority of potential composters. Moreover, if the EA maintain their position, it may be an impossible task to find appropriate sites for the 380 additional composting facilities that the DETR estimate will be needed to meet the demands of the Landfill Directive [Ref 14].

4.1.4. Feedstocks There are several types of biodegradable waste that are suitable for composting, and these waste types can be sourced through a number of routes.

4.1.4.1.Green Waste The term green waste is used to describe all types of waste plant material, from grass cuttings to felled trees. Commercial producers of green waste, such as landscape gardeners and tree surgeons, have a responsibility to pay for the disposal of the green waste they produce. These types of waste tend to be delivered directly to waste disposal facilities by tradesmen who are charged a rate per tonne. Separating the green waste from other waste streams is a fairly simple operation and is an ideal feedstock for composting. Similar material is deposited by the public at local authority civic amenity sites. Again, separating the green waste from other materials at the site is a fairly simple procedure. The local authority (usually the County Council) is responsible for the disposal of this waste, but will usually employ a contractor for this purpose.

4.1.4.2.Source Separated Source separated waste is rubbish that is sorted into specific waste types by householders for the purpose of separate collections by the local waste collection authority. The local authority can specify

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 13

4. Work Package One

which types of waste they will permit in the separate collection, and in some cases this will just be green waste. However, vegetable waste, dairy foodstuffs and meat may also be included in some circumstances, as may paper and cardboard, depending on the processing capabilities of the compost site to which the material is being sent. This waste stream is potentially very large, as it represents over half of the 27 million tonnes of household waste produced each year in the UK. Because of the magnitude of the waste stream, the growth of source separated collection schemes is likely to be strongest force stimulating the development of new composting sites across the UK in the coming years. Experience in other countries where this system is already in operation has shown that it produces a clean compost which can be used in an unrestricted manner.

4.1.4.3.Municipal Solid Waste (MSW) In rural areas, where the costs of transporting waste to disposal facilities may be considerable, it may not be economically or environmentally viable to separately collect and transport source separated wastes. A new area of composting is now developing which will allow the biodegradable portion of mixed household waste to be mechanically separated at the waste disposal facility and then biologically treated by composting. These facilities are known as MBT (Mechanical Biological Treatment) plants. The non-biodegradable fraction of the waste will inevitably need to be landfilled, but it is possible to divert some10-40% of household waste from landfill by this method, although techniques are currently developing. It has not yet been determined what quality this composted material should attain in order for it to be used outside of the landfill cells, if it should be used at all. Nor has it been determined if use of this material in landfill restoration work will qualify as a recycling and therefore contribute to meeting recycling targets.

4.1.5. Composting Methods and Technologies A report entitled the ‘The State of Composting’ [Ref 7] is published annually by The Composting Association, giving an overview of the types, numbers and capacity of composting sites in the UK. The overall picture for composting in the UK is one of continued expansion. Over the last five years the number of operational centralised composting facilities has grown, on average, by around 25% per annum, in 1999 there were 197 sites processing approximately 833,044 tonnes of material. Composting methods are many and varied [Ref 15]. However, in broad terms, the available methods can be divided into two classes: open-windrow and in-vessel. In 1999, The Composting Association’s report identified 152 sites using an open-air composting method, and only 7 using in-vessel composting methods. Open-air and in-vessel composting each have their own advantages and disadvantages, in terms of capabilities, cost and environmental impact. Open Windrow Composting

In-vessel Composting

In open windrow systems, waste is generally shredded and arranged in piles which may be turned periodically using heavy machinery to aid aeration.

In-vessel composting techniques enclose the waste during the active phase of decomposition, with forced aeration to supply the required oxygen. In some cases, the waste is mechanically mixed/turned within the vessel.

Primarily suitable for composting only green waste. Food waste in open windrows can attract vermin. Simplest form of composting, usually used for smaller, on-farm composting. Limited expenditure on machinery and equipment. Waste is slower to break down. Retention times are therefore longer and more storage space is needed. Rate of decomposition dependant on weather. Without forced aeration, decomposition may become anaerobic and odours may form in the composting material. Odour emissions from the material are uncontrolled.

• Odorous gases are contained within the vessel and treated before release to atmosphere. • Suitable for a wider range of waste types, including food waste and paper in some instances. • Oxygen is supplied and decomposition rates are optimised. Retention times can be shortened, and the facility footprint is reduced. • Suitable for larger, centralised facilities. • Higher investment in machinery and equipment. • Oxygen delivery reduces generation of offensive odours in the material. • Weather independent.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 14

4. Work Package One

4.1.6. Compost Standards In May 2000 The Composting Association introduced a set of standards for compost [Ref 16], which aim to encourage the manufacture of good quality compost and increase confidence in the product, by examining elements of the composting process and the end product itself. Whilst these standards have been adopted as a recognised industry standard and provide a benchmark for all UK composters to aspire to, participation in the scheme is voluntary. Elsewhere in Europe and in the US, such standards have been built into the appropriate legislation and act as driver in the development of new composting technologies and techniques. The Waste and Resources Action Programme (WRAP) has been established with government funding to promote sustainable waste management by creating stable and efficient markets for recycled materials and products. WRAP have identified a need for comprehensive standards for compost products and are in the process of commissioning an independent comparison of compost standards in the EU, North America and Australasia, which will inform the development of enforceable standards here in the UK. It is likely that a range of standards will be developed which will include a standard for unrestricted use and other standards that will enable composts to be spread under controlled conditions. Potentially Toxic Elements mg/kg

MSW Compost

Source Separated Compost

Zinc Lead Cadmium Copper Mercury

1570* 513* 5.5* 274* 2.4*

222* 68* 0.7* 50* 0.2*

12700# 2100# 2 5140# 39400# 3310# 2080#

10600# 010# 5900# 50100# 2140# 739#

225# <10# 1135# 8.3# 1750#

11# 8# 553# 8.9# 617#

Total Plant Nutrients in Dry Matter mg/kg Nitrogen Phosphorus Potassium Calcium Magnesium Sodium Plant Nutrients extractable in water mg/l Nitrogen (NH4+NO3) Phosphorus (P) Potassium (K) pH Conductivity mS/cm at 20oC

Table 2 Comparison of MSW and ‘Source Separated’ Compost * [Ref 17] # [Ref 18]

4.1.7. Conclusions with Respect to Composting in the UK The composting industry in the UK is currently in a stage of rapid change and development; the tonnage of material composted, the number of composting sites and the variety of techniques available are all increasing. In fact the legislation is in place that will effectively force the UK to divert a very large tonnage of material away from landfill. It is generally acknowledged that this will mean a dramatic increase in the tonnage of waste composted. The economic potential of composting is improving year on year and there is considerable support in local and national government for composting to become a significant contributor to a sustainable waste management strategy of the future. However, a very cautious approach to planning and licensing has lead to the introduction of legislation that impedes other directives and, at present, this is constraining the development of the composting industry. A

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 15

4. Work Package One

co-ordinated effort between industry and government has now begun to develop standards and protocols that are both practical and effective in providing assurances that composting is a safe and sensible method of recycling biodegradable wastes. These initiatives will probably result in large quantities of compost becoming available. One of the possible uses for such compost is as a primary resource for biofuels initiatives.

4.2 Composting and Short Rotation Coppice 4.2.1. Introduction The use of composted organic waste as a fertiliser and soil ameliorant for short rotation coppice will be explored further. There are a number of different reasons why composted material may be a useful component in the establishment and cultivation of short rotation coppice (SRC). Compost may be used to create the soil required to support the growth of coppice. In some areas there are many hectares of unproductive land, often called brown field land, on which it would not be possible to grow a viable biomass crop unless the land is remediated. This remediation may be the reduction of pollutants, but it may also include the substantial addition of organic matter to the soil. Organic matter is a fundamental part of soil fertility and therefore it has the ability to support a crop of SRC. Organic matter is responsible for sustaining soil micro-organisms and therefore the overall supply of nutrients to the plant. Soil organic matter is also an important factor in determining the moisture holding capacity of a soil. Compost made from organic wastes is high in organic matter, and could be used to formulate a soil suitable for SRC cultivations. A SRC cultivation requires approximately 300mm of soil depth. The amount of compost that could be used as part of the soil forming activity would be dependent on a range of local factors including the quality of compost, the amount of inert material available for blending and the overall site restoration requirements. Given a reasonably clean compost material with a moderate conductivity, such as the quality listed under source separation in Table 2 above, a reasonable assumption would be the use of between 25 and 50% vol/vol compost in a soil forming mix with inert material. This means that a brown field site could be expected to use up to 150mm depth of compost (1,500 m3 compost/ha). The factors that will influence the usage rate would include the level of available nutrients and the pH, the conductivity of the compost and the risk to groundwater from the leaching of nutrients (particularly nitrates) from the site. The recycling of green wastes generates a mulch fraction that is widely used in the amenity market for weed control. A woody fraction from the composting operation is screened to remove the fines and then graded for use a mulch. This fraction is applied as a deep layer to the soil to aid moisture retention and to inhibit weed growth. One of the major costs involved in the establishment of a SRC is the use of weed killers to suppress other plants while the coppice plants become established. As a fresh compost or mulch would not be expected to contain viable weed seeds as a result of the pasteurisation process involved in the composting process, there seems to be the potential to use compost or mulches to assist in the establishment of a new stand of SRC. This hypothesis would need to be evaluated and tested but it might result in a substantial use of compost at least in the early days of any future project. An established crop of coppice will deplete the soil of nutrients as the stand is cropped. The leaching of soil nutrients will also be a factor in the deterioration of the soil fertility. Compost could be a suitable material for the top dressing of any existing stand of SRC. The objective of this activity would be to enhance the productivity of the coppice stand through plant nutrition, to aid in the control of weeds and to provide a beneficial use for the compost. From Table 2 it can be seen that both types of compost could provide a significant amount of plant nutrients. These will not be at the correct balance for the plant requirements and some blending of other nutrients may be appropriate. The use of compost topdressing at a strategic time in the cultivation cycle may reduce the amount of chemical herbicides that are required. The use of a SRC stand as a long term sink for compost would offer the compost operation a significant outlet for the compost in a non-food use application. This would be very attractive to most compost plant operators. Some research has been undertaken into the use of sewage sludge in the cultivation of SRC and the results are encouraging [Ref 19, Ref 20].

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 16

4. Work Package One

4.2.2. SRC and Landfill sites To determine the potential of landfill sites as potential areas for the cultivation of SRC and as a source of compost through on-site processing, two sites have been considered as case studies. The following Tables illustrate the waste input compost output potential.

Scenario

Waste input (t/yr) Compost yield Compost out (t/yr) Compost out (m3/yr)

A1

A2

A3

A4

MSW min 400,000 10% 40,000 66,667

MSW max 400,000 30% 120,000 200,000

Source sep. min 40,000 30% 12,000 20,000

Source sep. max 40,000 50% 20,000 33,333

Table 3 SITE A - Four compost production scenarios with two waste streams.

Scenario

Waste input (t/yr) Compost yield Compost out (t/yr) Compost out (m3/yr)

B1

B2

B3

B4

MSW min 120,000 10% 12,000 20,000

MSW max 120,000 30% 36,000 60,000

Source sep. min 30,000 30% 9,000 15,000

Source sep. max 30,000 50% 15,000 25,000

Table 4 SITE B - Four compost production scenarios with two waste streams. The assumptions behind these estimates can be challenged and there is not enough published quantitative research data on which to base any firm opinion, but the data does indicate the scale and range of potential compost production from two landfill operations. The most probable scenario may be a mid way point between the minimum and maximum compost production scenarios in which a large proportion of mixed household waste is collected separately and then composted. However, for the purposes of this study only the extremes are to be considered. For each of these two sites, the compost output has been considered in the light of the potential for utilisation of the compost on the landfill itself. The following tables illustrate the proportion of the total production that could be utilised as topdressing on established SRC.

Scenario

Frequency of dressing (yrs) Area to be dressed (m2/yr) Compost applied per m2(m3) Compost applied t/ha Depth of application (mm) Nutrients applied t/ha Nitrogen Potassium Phosphorus

A1

A2

A3

A4

MSW min 3 240,000 0.278 1,667 278

MSW max 3 240,000 0.833 5,000 833

Source sep. min 3 240,000 0.083 500 83

Source sep. max 3 240,000 0.139 883 139

9.53 1.58 3.86

28.58 4.73 11.57

2.39 0.45 1.33

3.98 0.75 2.21

Table 5 SITE A – Potential application rates of compost and nutrients.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 17

4. Work Package One

Scenario

Frequency of dressing (yrs) Area to be dressed (m2/yr) Compost applied per m2(m3) Compost applied t/ha Depth of application (mm) Nutrients applied t/ha Nitrogen Potassium Phosphorus

B1

B2

B3

B4

MSW min 3 590,000 0.034 202 34

MSW max 3 590,000 0.101 607 101

Source sep. min 3 590,000 0.025 152 25

Source sep. max 3 590,000 0.042 253 42

1.16 0.19 0.47

3.47 0.57 1.40

0.72 0.14 0.40

1.21 0.23 0.67

Table 6 SITE B – Potential application rates of compost and nutrients. These tables indicate that whilst the site would be able to accept the amount of source separated composts that are likely to be generated, they would not provide a realistic sink for the maximum potential diversion found in the MSW scenarios. Similarly, the area of a landfill cap that could be cultivated into willow would be unlikely to sustain a power plant. These issues are discussed in more detail later in this report.

4.2.3. SRC and the treatment of leachate The water demand of a standing crop of SRC is of the order of 400 – 600mm rain. This moisture is lost through evapotranspiration by the plants. It is possible that some of the water demand of the crop might be met through the application of leachate to the coppice area. Should this arrangement be possible it would be a useful contributor to the overall economic performance of the project. However, both the water status of the soil and the quality and quantity of leachate are variable and it is not possible to model such as system with the available information. The two areas of concern for any such proposals would be the conductivity that any leachate would contribute to the soils. Compost materials are generally quite high in salts and therefore make an important contribution to the conductivity of a soil/compost mix. This contribution is offset to some extent by the inherent cation exchange capacity of the compost. However, any addition of leachate will almost certainly affect the conductivity of the soil onto which it is applied. High conductivity adversely affects the growth of most plants and therefore there will be an upper limit to the use of any leachate. The other factor that might limit the use of leachate is the level of plant nutrients in the leachate and the soil. Level of plant nutrients that are imbalanced or just too high can also reduce SRC yield or lead to plant death. In addition to the uptake and utilisation of the nutrients by the crop, there is significant loss of certain nutrients through volatilisation and leaching. Both of these factors will be site specific and heavily influenced by soil and climate. It would be a most useful addition to our understanding of the potential for integrated biological treatment if we were able to model and predict such limitations. However there is insufficient data to enable this to be undertaken at the present time. This would be a most useful area for further investigations once a suitable SRC area is established.

4.2.4. Other uses for compost For the purposes of this study, the use of compost as a part of the method of SRC cultivation has been considered. However, it is also probable that there will be other applications for compost. Compost that meets the criteria for unrestricted use will find many other uses, such as general landscaping, amenity grounds maintenance, gardening and horticulture. Compost that fails to meet the standard for unrestricted use will have other outlets. These outlets will be constrained in ways similar to the regulations that control the use of treated sewage sludge. The experience of composting operations in Germany and elsewhere would suggest that a broad spectrum of uses will be found according to local circumstances. This matter should be borne in mind when considering the output from a composting operation.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 18

4. Work Package One

4.2.5. Composting and Anaerobic Digestion Anaerobic digestion is the breakdown of organic matter by micro-organisms in the absence of air. This process generates a gas that is 55 to 70% methane and 30 to 45 % carbon dioxide. Anaerobic digestion (AD) is a natural process but it is not thermophilic to anything like the same extent as composting. It does occur in landfill cells, but when it is being used as a method of treating waste it is undertaken as an in-vessel process. AD is a suitable method of treating any of the wastes previously mentioned, but it is not the most common form of treatment. The advantage of AD is that the process yields a gas that can be burnt for power generation and therefore the process is more energy efficient than composting. The principal disadvantage of AD is that it requires the infrastructure of gas combustion and power distribution as well as the infrastructure of AD and compost maturation. The capital costs of an AD facility are considerable higher than that required for composting. That is not to say that in all circumstances AD is less cost-effective. About a third of the biological process plants built in the EU in recent years have been AD rather than composting plants. However, they tend to be plants with higher throughput, long term electricity contracts and a use for the waste heat derived from the burning of the gas. Unfortunately, there is only one operating AD plant treating solid wastes in the UK and this is very small (<5000 t/a). It is not possible to readily access appropriate plant capital or operation and management data relevant to the UK. The data from mainland Europe shows a wide divergence of operating performance depending on the technology used. A recent paper [Ref 21] illustrates these differences and reports a 40% difference between two operating plants processing the same feedstock but using different technologies. It is therefore suggested that the use of AD as the method of treating the organic waste should be considered in the future, but such a development will require considerable reduction in the cost base for the AD treatment processes to become cost-effective option for the UK in the near future.

4.2.6. Conclusions with Respect to Composting and SRC The amount of organic waste materials that are going to be composted in the UK can be expected to rise dramatically in the foreseeable future as a result of legislative requirements. Many landfill sites will be used as a location for the composting activities and composting has the potential to provide soil forming materials that are required for landfill restoration including the use of SRC as part of the restoration and aftercare programme. SRC on the capped landfill may be able to assist in the treatment and disposal of certain leachates, through the evapotranspiration of the SRC. There are no known difficulties with the cultivation of SRC on landfills if the soil depth and quality is appropriate. Compost has the potential to provide both plant nutrients and the soil organic matter required to generate a suitable soil for the cultivation of such crops. There is also the possibility that compost could be used both as a weed control agent and as a top-dressing on established stands of SRC. Both of these applications require further research and testing. The factors that may limit the use of compost in the cultivation of SRC are nutrient loading and soil conductivity. Both issues require further study to determine how these limitations will affect the overall potential. The remediation of brown field sites, such as industrial land and quarries, is a recognised use for compost. Compost therefore has the potential to enable some substantial areas of land to be brought into beneficial use as areas for the cultivation of biofuels.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 19

5. Work Package Two

5. Work Package Two Potential for Growing SRC at Landfill Sites

5.1 Introduction to SRC Short rotation coppice is an intensive management system which has been used on woody species principally willow (Salix) for basketry, hazel (Corylus) and sweet chestnut (Castanea). It is a perennial crop exploiting the natural ability of the majority of our native broadleaf species to regenerate from cut stumps after harvest (coppicing). The harvesting cycle is from two to five years depending on the productivity potential of the site and in economic terms plantations can be envisaged as having a life of 15-30 years. The botanical family Salicaceae is composed of two genera Populus (poplar) and Salix (willow), both contain largely northern temperate species with Populus more prevalent in the warmer latitudes and Salix in the cooler and wetter areas. Both genera have common properties, which distinguish them from other woody species: •

Generally propagation is vegetative i.e. from cuttings rather than seed because they root easily producing adventitious roots from pre-formed initials within the bark.

•

Juvenile growth can be extremely rapid and sustained over a number of cutting cycles.

•

They coppice well i.e. they regenerate easily after harvest from dormant buds at or below ground level.

Figure 5 Coppice Regrowth 6 Weeks from Harvest

•

They are hygrophilous species using much larger amounts of water in their growth than other woody species – a distinct advantage where they are being deployed in the management of wastewater or effluent problems.

•

They are generally recognised as pioneer species – they have the ability to establish in soil conditions, which are far from ideal and are often one of the first colonisers of disturbed sites.

•

As an energy crop they are carbon dioxide neutral. That is to say there is no net addition of carbon dioxide to the atmosphere through using SRC willow as an energy source. The growing crop uses at leas as much carbon dioxide in its growth as it releases on conversion to heat or electrical energy.

•

Established willow coppice has a high economic threshold to pest and disease damage and unlike all arable and food crops cosmetic damage is not important unless yield is affected.

•

Willow coppice is generally viewed as beneficial to wildlife creating habitat and increasing the opportunity for biodiversity. Willow supports a wider range of insect life than any other tree species and will attract a wide range of bird life associated with woodland margins and grassland.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 20

5. Work Package Two

Salix is the bigger of the two genera containing over 300 species. These occur from the Arctic Circle to latitude 30°, and further south. Approximately twenty species are native to the United Kingdom. However, Salix viminalis or the common osier and its hybrids remain the most important species in the context of short rotation coppice systems. Willows have many local names, Sallys or Sallows, Withys and Osiers, however, the botanical name Salix derives from two Gaelic words ‘Sal’ meaning near and ‘Lis’ meaning water, indicating the adaptation of the genus to these conditions. However, although this is true, their roots containing specially adapted aerenchyina cells allowing them to withstand periods of flooding, they do not thrive in areas of standing or stagnant water.

5.2. Site Selection Elevation Generally sites above 100m above sea level will begin to show a drop off in yield due largely to exposure and a reduction in ‘growing days’. Accumulated temperature figures above 5.6oC will give a reasonable fix on the degree of yield depression. As a general rule accumulated temperature figures above o 900-1000 C will be satisfactory. This is not an absolute elevation figure as other local factors such as topographical shelter, aspect and soil will also have a bearing on the outcome. However, on the proposed site, elevation (180m), exposure (it is the highest point in the immediate landscape) and soil conditions (low nutrient status and compaction) will all have an impact on yield levels. • Soils: SRC willow will establish and grow on a wide range of mineral soils (<10% organic matter) over the pH range 5.5 – 7.5. Optimum levels range between 5.8 – 6.5. Generally highly organic soils (10-25% organic matter) or peat soils (>25% organic matter) should be avoided because of the difficulty of weed control in both and in the case of peat or peaty soils, overall nutrient availability and pH can be a problem.Soil Moisture: The crop can be expected to loose 400-600 mm of water through evapotranspiration during the growing season, depending on yield. Either precipitation in excess of this level during the growing season or good moisture retentive soils are necessary. In this latter case soils with above 30% clay (<0.002mm) would be ideal i.e. clay soils or clay loams. Shallow or dry sandy soils may well give poor yields. Rainfall figures for the proposed site (mean 1961-1990-530mm) are within the range needed. • Nutrition: For P, K and Mg index level 7 is the point at which the level of plant available nutrient is considered excessive. Index 7 equates to 141 – 200 mg 1-1 P, 1501 – 2400 mg l-1 K and 601 – 1000 mg 1-1 Mg. Adequate levels will be supplied from index 2 equating to 16-25 mg 1-1 for phosphorus, index 3 for potassium, 241-400 mg 1-1 K and index 2 for magnesium, 51 – 100 mg 1-1 mg. Nitrate nitrogen – at index 4 (151-250 mg 1-1) levels are considered excessive for crop growth. Levels from 26-50 mg 1-1 (index 1) are satisfactory. • Microelement mineral indices – Copper, Zinc and Boron. Generally for plant growth index 4 marks the extreme of the range for these elements. This corresponds to >6 mg 1-1 Cu, >3.5 mg 1-1 Zn and 4mg 1-1 B. These indices have been established for arable crops and it is known that Salix as a pioneer species will tolerate higher levels but absolute values are not known. Consequently, it would be desirable though not imperative that these levels should not be exceeded. Comprehensive soil analyses will be required before planting on all sites. • Conductivity: As with the microelements no absolute value has been placed on the point at which growth in SRC willow is adversely affected by conductivity. However, it is generally accepted that above 3,000 micro-siemens damage will occur on all crops. Willow may be more tolerant but for optimum growth, index levels should be below index 5 (2810 – 3000 micro-siemens) as calculated using saturated CaSO4 solution. The composted organic which it is proposed to incorporate into the clay capping of the site will have values outside these limits. However, there will be an element of dilution involved as well as the extensive buffering capacity of the clay soil. Therefore, the cation exchange capacity is also relevant though not normally referred to in an arable crops context. Again crucially analyses after incorporation will be required.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 21

5. Work Package Two

5.3. Plantation Design Plantation design in SRC willow should be considered at three levels. Firstly, its overall location in the landscape in relation to topography, enclosure patterns and existing agricultural use. At the next level, location within the farm or the structure of the more local landscape should be of concern taking account of access, storage etc. Finally, design at plantation level must take into account a range of technical considerations from spacing to disease control. • Design in the landscape: In this particular project the parameters are more fixed than they would be in an agricultural context. However, there are overlying principles that should be taken account of. Plantations should be of a size and shape in sympathy with the surrounding landscape. Irregular interlocking planting blocks responding to the overlying topography will provide a more organic shape pattern than regular geometric layouts. The existence of mixed age classes corresponding to harvesting patterns and the deciduous nature of the crop also creates a seasonal diversity of texture and colour. It is often a concern that, at the level of utilisation being considered the introduction of SRC into the landscape will have a major impact. However, if the commonly proposed maximum supply distance for a centralised conversion facility of 20km is accepted a 1% uptake within the supply area would give 1250 ha or the equivalent of 2.0 MWe generation capacity. • Design at facility level: At this level, of primary practical importance is access to all-weather roads to facilitate machinery access and crop extraction. Harvesting is carried out in the dormant season when land carrying capacity is at its lowest. In normal coppice 70-90 tonnes of crop per hectare will have to be transported from a mature three-year-old plantation at harvest. Planting with the site contours rather than in straight lines, where this is consistent with ease of harvesting, will improve the visual aspect and enhance the opportunity to avoid run off, improving the utilisation and remediation of any applied leachate. Within the landfill there is also the opportunity, with carefully planned planting, to provide screening for the active part of the facility and interception of wind blown material. • Design at plantation level: The design elements at individual plantation level concern a wide range of technical/management aspects. As such they can take the form of more direct recommendations rather than the landscape and facility design. Considerations, which by their nature, relate directly to particular environmental and visual aspects of individual sites. • Planting density: Experience has been gained with a wide range of planting densities (40,000 ha-1 to 5000 ha-1). However, the current trend is to adopt densities between 12,000 ha-1 and 15,000 ha-1. Higher densities up to 20,000 ha-1 may be appropriate on poorer sites to account for potential losses at planting and to improve yields in the first rotation. Like other plantations these are likely to self-thin to 12,000 ha-1 to 15,000 ha-1 over a number of harvesting cycles. • Spatial arrangement: To facilitate mechanisation of the crop it is normally established in double rows 1.5m apart. The spacing between the double rows should be 0.75 m and between plants within the rows 0.44m. This will give a final planting density of 20,000 ha-1. On large sites designed for sequential harvesting it is preferable to avoid parallel strips that would be harvested on consecutive years. An interlocking pattern should be chosen with perhaps a variation in row orientation consistent with maintaining adequate row length for efficient planting and harvesting. • Headlands/Rides: The inclusion of headlands and rides in plantation design will not only optimise the opportunity for biodiversity but it is practically is necessary to facilitate mechanical operations in the plantation. Headlands should be a minimum of 6.0m - 10m to allow for machinery turning particularly during harvesting. Soil type and rainfall also have an impact, where annual rainfall is low (400-500 mm) and drainage acceptable, the headlands may be left unplanted. However, in conditions of poor drainage and where rainfall is high (1000-1200mm) the headland may have to be planted with coppice to improve the soils carrying capacity and reduce damage to soil structure. The spacing of internal rides can be determined by the capacity of the extraction vehicles used at harvesting or the requirements (distance of spread) of machinery for sludge dispersal etc. They should also coincide with agricultural equipment sizes used for other management operations e.g. weed control. Mixtures: Willow as a species is vulnerable to attack by a foliar rust disease (melampsora), which can have devastating effects due to premature leaf fall and the entry of secondary die-back organisms. This disease can be controlled using fungicides but this is not acceptable on environmental or economic

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 22

5. Work Package Two

grounds. Further on a 2-3 year old stand it would not be practically possible to get adequate fungicide coverage of the crop to give effective control. In these circumstances the use of mixtures has been shown to be effective in reducing the impact of the disease to an acceptable level. Mixtures also show a yield increase over the mean yield of their component varieties grown in monoculture. Although research work on mixtures is continuing, several definite recommendations can be made – the mixture should be as diverse as possible containing 6-10 varieties and varieties that have shown any rust susceptibility should not be included. In addition intimate random mixtures are likely to give the best protection in terms of spread of the disease and offer the best opportunity for yield compensation in the event of a mixture constituent dying out because of disease or other reason. Row or block (mosaic) mixtures could not provide this level of yield compensation and may indeed facilitate pathogen build up.

5.4. Plantation Establishment • Land Preparation: The site should be deep ploughed in the autumn before planting following herbage removal using glyphosate herbicide. A minimum cultivation of 20cm is necessary to ensure adequate depth for cutting establishment. Willow coppice in a landfill context can be expected to have a rooting zone of approximately 30cm. Consequently, if the integrity of the cap is an important issue, this capping should be in addition to the statutory requirement for the cap. Immediately prior to planting cultivation using a power harrow will provide an adequate tilth for planting. • Cuttings: Cuttings are prepared from one-year-old healthy vigorous stems either as full stems for mechanical planters or as prepared 20cm cuttings for hand or modified planters. Cuttings/stems must have a minimum diameter of 8mm to ensure maturity and sufficient reserves for establishment. Cuttings should be obtained from a specialist producer who will have access to improved planting stock. Planting is ideally carried out in March, however, if delayed because of weather etc, cuttings can be stored successfully at – 2oC till early-mid May. Soaking cuttings by standing them upright in water for 24 hours prior to planting, particularly on sites where environment and or soil conditions are not ideal will improve initial establishment. • Planting: Cuttings are inserted on the prepared site normally using specialised equipment. For this reason a contractor should be used. For the landfill situation a higher initial planting density of 20,000 ha-1 will ensure an adequate establishment level, given the adverse conditions, and improved early yield in the first rotation. On ex-farmland sites however densities of 12,000 ha-1 to 15,000 ha-1 are satisfactory. This will be obtained with an in-row spacing of 60-74 cm where there is 1.5 m between double rows whose individual rows are 0.75 m apart. If, because of site conditions or climate, the headlands of the plantation are to be planted these rows should run parallel to the boundary of the site to facilitate ‘opening’ of the site for harvesting. When planting is complete the site should be lightly rolled to consolidate the cuttings and present a soil surface that will maximise the effect of residual herbicides. • Post Planting: Weed control is the single most important factor in the successful establishment of SRC willow. Providing the initial kill of weeds has been good with the pre-planting application of glyphosate, a post-planting application of simazine will provide adequate weed control for year one. Perennial weeds where they occur will require individual spot treatment [Ref 22]. • Disease: Foliar rust caused by Melampsora epitea is the single most limiting factor in sustainable production from SRC. Currently the accepted strategy to reduce disease impact to a minimum is to use varieties with improved disease resistance and to plant them in mixtures. Mixtures should be as random as modern planting machine will allow and should contain as wide a range of varieties as possible. In conditions in Northern Ireland mixtures of the Salix viminalis varieties ‘Orm’, ‘Ulv’, ‘Jorr’ and ‘Joruun’ and the hybrid ‘Tora’ have given good results. Where newer varieties such as the S. burjatica x S. viminalis hybrid ‘Aston Stott’ are available they should be included in the mixture to increase it’s diversity and improve the opportunity for yield compensation should an element of the mixture become susceptible to pest or disease. • Cutting back; The final act of establishment is the cutting back of the first years growth in the winter following establishment. This gives a second, all important opportunity to ensure that weed control is satisfactory and promotes vigorous regrowth the following spring. Stems of established cuttings should be cut back to 5 cms and this can if necessary be followed by a second application of residual/contact herbicide while the stools are skill dormant. Amitrole + Simazine has been shown to be a successful

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 23

5. Work Package Two

mixture and willows have shown some level of resistance to this mixture. Where establishment has been good and growth vigorous, producing 2 stems 2-3 m tall from each cutting, cut-back may not be necessary. However this is unlikely on sites that have some level of disadvantage either through soil conditions or environment/climate. • Cropping/Yield: High yield levels in excess of 20 tonnes of dry matter per hectare per year have been obtained from experimental plots. Whilst recent introductions from breeding programmes have improved yields significantly, in the practical situation it is not realistic to expect production at this level. A yield of 10-12 tonnes of dry matter per hectare annually is a more realistic and sustainable target from suitable agricultural sites. • In the case of the proposed sites, both on the capped landfill and adjacent ex-farmland, account will have to be taken of elevation and exposure, and on the landfill of soil quality and compaction. For this reason realistic yield estimates for the ex-farmland will be 6-8 tonnes DM ha-1 yr-1 and on the landfill 4-6 tonnes DM ha-1 yr-1. These are the figures which will be used in the calculations for generation potential from the various sites.

5.5.

Establishment Costs There are major difficulties in arriving at robust costs for establishing SRC willow in the United Kingdom because

• there are relatively few commercial areas of willow to provide actual costs • it has been shown that ‘pioneer’ growers of SRC will incur greater costs in all spheres of operation compared with growers where there is significant activity in the sector. Comparison of costs in Sweden where establishment costs are £700-900 ha-1 with those in the United Kingdom estimated at £1700-1900 ha-1 illustrates this point. Based on a 5.0 ha plot and using a planting density of 15,000 ha-1 the breakdown of establishment costs is shown in the table below.

Operation

Costs £ ha-1

Fencing Cultivations Planting and Materials Weed control Cutting back Total Cost ha-1

370 90 1100 150 50 1764

The major cost is obviously the planting and cuttings and is based on a cutting price of £70/1000 and using the Salix Maskiner ‘Step Planter’. Some of the newer varieties from the breeding programmes in Sweden and England may be more expensive but as in other areas this cost is likely to reduce with increased scale of operation, and their increased productivity will also reduce overall production costs. Overall production costs including plantation management and harvesting are again at this stage difficult to estimate because of the lack of real data. However, based on a crop of 10t dry matter per hectare per year the average costs of growing SRC over a 25 year rotation (8 x 3 year harvests) can be estimated at £300 per hectare annually. These costs are obviously dependant on scale of operation degree of mechanisation etc. and will also be influenced significantly by crop yield.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 24

5. Work Package Two

5.6. Support There are a number of schemes that support the establishment of SRC. The main vehicle currently is the Woodland Grant Scheme (WGS) and although supplementary aid though the Arable Area Aid Scheme is given on setaide land, grassland is only eligible for WGS support, (Table 7).

Support Scheme WGS Arable Aid

Setaside 400 1500 (5 annual payments) 1900

Total

Non-setaside 600

600

Table 7 Support Schemes

There is obviously a serious imbalance of support between grassland (non-setaside) sites and setaside sites. This has been addressed in the Rural Development Plan, which has been adopted for England, where the EU have approved an up-front payment of £1600 ha-1 for the establishment of SRC on grassland. The other UK regions have yet to finalise their support initiatives on non-setaside but there would be little agreement for significant variation from that adopted in the English scheme. Recently the National Lottery has announced the New Opportunities Fund and has released a consultation document. There is specific provision within the Fund for support for renewable energy under section 8 “Transforming Communities”. Indirect support also exists though the climate change levy [Note 5], which imposes a levy of 0.43 p kW-1 on industrial energy from fossil resources. Renewable energy technologies are exempt from the levy.

5.7. Bioremediation Where SRC is to be used as a bioremediation/management system, either for leachate arising on sites or for sewage sludge imported onto the site, maximising yield is of paramount importance. Obviously the more productive the coppice system is the greater its potential for handling wastes. On suitable agricultural sites the use of artificial fertilisers can be justified from an energy balance standpoint to optimise yield. In terms of plantation management, fertilisation will require at least the replacement of those plant nutrients exported from the site at harvest. Nutrient export data from a trial site in Northern Ireland, with similar climatic conditions though lower rainfall, indicates that 4.6 - 5.5 kg N, 0.7 kg P and 2.6 kg K are exported per tonne of harvested dry matter. These nutrients can be supplied in a number of ways but both leachate from the landfill and sewage sludge will contain some plant nutrients if, not always, in the correct proportions. • Landfill leachate: SRC can deal with large quantities of water in its growth and in comparison with other woody species uses significantly greater quantities. Figures of the equivalent of 50 mm of precipitation per tonne of dry matter produced lost through evapo-transpiration have been quoted. This provides ample opportunity for irrigation with leachate. The ability of the willow coppice roots to absorb plant nutrients and non-nutrients and of the plant soil system to significantly reduce BOD & COD is the basis of the bioremediation and chemical export from the site at harvest. It is by no means clear how much leachate an SRC system can deal with or what the long term effects on the soil-plant system will be. Ongoing work at Water Research Council is looking at rates of leachate application. • At a site in Londonderry where SRC productivity has been in the range of 8-10 tonnes dry matter per hectare per year, waste water has been applied at one, two and three times the calculated evapotranspiration rate. Yield estimates have indicated an increasing productivity with increasing

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 25

5. Work Package Two

wastewater application. Irrigation rates for those plots irrigated to potential evapotranspiration corresponded to 1.7, 1.9, 3.3, 3.7, 3.3, 2.6 and 2.5 mm per day in April, May, June, July, August, September and October 2001 respectively giving a total 19mm per day over the period April to October 2001. Analysis of the ground water in plots which had received up to three times this level of irrigation did not show any significant level of contamination with NPK or trace metals contained in the waste water, indicating the effectiveness of SRC willow as a biofilter. Equally important in the practical application of such a system was that there were no detectable levels of any significant human pathogens in the groundwater either. • Sewage Sludge: As indicated, the addition of nutrients, at least to the level at which they are exported off-site in the harvested biomass, will have positive effects on total yield and the sustainability of the plantation. These nutrients may be added when the nutrient capital of the site has been exhausted to the point where deficiencies become apparent or they can be replaced as they are exported through harvest. The latter has been the case with all conventional arable crops, and is likely to give the best results. Evidence would suggest that once a coppice plantation has been challenged through nutrient deficiencies it is extremely difficult to bring it back to its full potential. Trials have indicated that, on annually harvested crops, 50-100 m3 ha-1 of sewage sludge could be applied annually and that yield was significantly greater where sludge was applied. These results may not be evident until the nutrient capital of the sites is sufficiently depleted to affect yield. Sewage sludge will provide both N and P but not K. Within this project no further consideration of the potential to use sewage sludge as a method of improving yields of SRC was carried out as it was felt such a system would be viewed as negatively impacting the neighbourliness of landfilling. • In addition, fully hardened wood ash could return remnant nutrients (except N) to the soil in a slow acting form. However, the ash produced directly from a gasifier type CHP unit would not be suitable without further treatment [Ref 34, Ref 35]. The small amounts of ash produced by a CHP unit could not economically justify the cost of treatment and spreading on the SRC.

5.8. Potential Production of SRC from Greengairs and Riggend Sites In this section a detailed assessment is made of the potential to produce SRC from the Greengairs and Riggend landfill sites. On-site discussions indicated that within the site boundary all areas were potentially available for SRC production. The site elevation is 180 m and the total rainfall is 1035 mm (30 years average 19611990). Greengairs Site 1. 33 ha approximately. This is a relatively uneven site and has in the past been an open cast working. Clumps of scrubby alder and willow have established naturally and the vegetation indicates that it is largely peaty in nature. It also has areas of open water and, as such, presents an area rich in habitat. It is a valuable area for improving the biodiversity on the site. This, taken with its relatively low potential for biomass yield, would indicate that it should not be considered as a biomass production area. Site 2. 15 ha approx. This is a capped area of landfill where the fill has been sealed with 1.0 m of clay cap topped off with 100 mm of ‘soil’. Given the 300 mm rooting requirement for willow this would require additional material to preserve the integrity of the cap. This could be provided by the importation of further soil and or the incorporation of compost prepared from recycled organic material. Although the compost itself would not be suitable, because of high conductivity figures in particular, it has the potential for incorporation into the soil layer above the clay cap. In this way the nutrient value of the soil would be improved and, through the extensive buffering capacity of the soil, the compost would be more amenable to plant growth. This site could potentially produce 60-90 tonnes DM per year. However, because of the need for more cover on the cap, realistically it would not be available for planting in the coming year. Additionally, being within the foot print of the landfill site and therefore contained within the bund, this area could be utilised for the management of leachate by irrigation over the SRC. Site 3. 20 ha approx. This is very similar in origin and capping to site 2 and would have the same potential for compost incorporation and leachate irrigation. Potentially it could be expected to give a yield of 80-120 tonnes DM per year. Again, as in site 2, its use is not immediate as it requires further work prior to crop establishment. Both sites 2 & 3 will in practice have a reduced cropping potential because of the network of

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 26

5. Work Package Two

pipes and valves associated with methane collection. This reduction will be between 10 & 15%. Site 4. 14 ha approx. This is an area of active filling and the competed areas have a 1.0 m clay cap only. Potentially it has the opportunity for compost inclusion in the ‘soil’ above the cap and leachate irrigation. It would be the last area within the landfill to be planted and has a production potential of 56-84 tonnes DM per year, though this would also be subject to a 10-15% reduction when the pipework for methane collection is installed. The area south of sites 3 and 4 is largely disused opencast workings or peat land and is not suitable for SRC production. Site 5. 37.0 ha approx. This is an area of abandoned farmland within the landfill site currently used for summer grazing only. It has not been filled at any stage. A combination of elevation and evident low productivity of adjacent agricultural land means that it could be expected to yield 222 - 296 tonnes DM per year. This site is outside the bund so would not be considered suitable for leachate irrigation. However, as SRC willow is a non food crop, the application of sewage sludge could be considered a possibility. In its most simple form digested sludge could be applied after harvest every third year. Rates up to 100 m3 ha-1 could be used giving a usage on the site equivalent to 3700 m3 every three years. Normal soil analytical data will be required from this site. It is immediately available and if required could be planted in the spring of 2002 following preparation in autumn 2001.

Riggend landfill, at a similar elevation to Greengairs is an 80 ha site. It contains, a) 15-20 ha area of capped landfill. It does not have a soil layer above the clay cap and would therefore align itself naturally with site 4 at Greengairs. It has a production potential of 60-120 tonnes DM per year. It would also have the capacity for compost use and leachate management. b) An area extensively planted with conifers with a relatively small unplanted area. The small size and the obviously very poor soil conditions would leave this unsuitable as an SRC area. c) 16 ha of ex-farmland with the same potential as area 5 at Greengairs - 96-128 tonnes DM per year. It could similarly be used for sludge application giving the potential of a further 1600 m3 every three years at harvest. Combining these sites in the following order would give the capacity for 130-150 kW electricity generation.

Year 1

Site 5 Greengairs 37 ha ex-farmland Total Potential Yield 220-290 t DM per year

Year 2

Site 3 Greengairs 20 ha landfill - Potential yield (80-120 less 10%) = 72-108 Site 2 Greengairs 15 ha landfill - Potential yield (60-90 less 10%) = 54-81 Area (c) Riggend 16 ha ex-farmland - Potential yield = 96-128 Total Potential Yield 222-317t DM per year

Year 3

Site 4 Greengairs 14 ha landfill - Potential yield (56-84 less 10%) = 50-76 Area (a) Riggend 15-20 ha landfill - Potential yield (60-120 less 10%) = 54-108 20 ha of contracted-in SRC = 120-160 Total Potential Yield 224- 344t DM per year

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 27

6. Work Package Three

6. Work Package Three Integration of Wood Fuelled CHP at a Landfill Site

6.1 Wood Fuelled CHP 6.1.1. Process Overview The figure below is a schematic of a wood fuelled CHP system.

Combined Heat and Power (CHP) is the on-site generation and use of heat and electricity. In a CHP system a turbine or engine is connected to an alternator to produce electricity, while the engine jacket and exhaust heat is used to produce steam or hot water. The standard CHP technology uses fossil fuels, typically natural gas or diesel oil, to fire a turbine or engine. With the B9 Energy technology the engine is fired on a syngas produced by the gasification of biomass wood chips. Biomass gasification is not a new process, indeed it is nearly 200 years since wood gas was first used to produce power. However, it was in Scandinavia, during the first half of the last century that most of the development work on a biomass gasifier system to generate fuel gas to drive an engine was performed. This technology was used extensively during World War II when imported liquid transport fuels were not available. After the war the development slowed down due to the renewed supply of cheap oil, but during the oil crisis of the 1970’s, further research occurred. Gasification is the process of converting the carbon and hydrogen in the original feedstock into a gaseous mixture of mainly CH4, CO and H2. This process takes place when wood is heated with some air, but with not enough oxygen for complete combustion to CO2 and water. This partial oxidation at elevated temperatures occurs at between 900°C and 1100°C. The products from the B9 Energy Biomass CHP system are therefore renewably produced electricity and heat. Overall the system is highly energy efficient. A 400kWe unit would require 4 deliveries of wood per week, produce electricity equivalent to the requirement of 800 homes, and a heat equivalent of 100 homes. A larger 1200 kWe unit would require 12 deliveries of wood chips per week, produce electricity, equivalent to the requirements of 2400 homes, and a heat equivalent of 300 homes.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 28

6. Work Package Three

6.2.

Wood Fuel Supply Strategy Within this project the plan is that the CHP is fuelled from SRC willow grown on the landfill sites and in the surrounding areas on brown field sites and agricultural land. However, the CHP unit may be fuelled by any combination of the following sources [Ref 23, Ref 30, Ref 31, Ref 36, Ref 37]: • • •

Short Rotation Coppice Willow (SRC). Sawmill woodchips. Forestry residues.

Considering the availability of the land area of a typical landfill site the unit will most likely be fuelled from a combination of the above sources. In the short term, until four years after establishment, SRC would not be available to fuel the CHP. Therefore, one of the above sources is needed to provide intermediate supply. When the fuel is to be purchased solely from sawmills the supply chain is straightforward and the material would be purchased to an agreed specification and transported directly to the CHP by the saw mill’s own transportation system. Because of the nature of the saw milling industry there is little option for the purchase of pre-dried wood chip and the CHP plant would require drying facilities. A review of the availability of sawmill wood chips in the central Scotland area identified ten potential wood chip suppliers. Following an evaluation of the wood chip, price and current contractual arrangements a short list of five suppliers capable of providing fuel to such a CHP plant was established. Total chip production from these companies is estimated at 580 tonnes per week, equivalent to 290 odt/week. The average wood chip delivered price is £18.95/tonne of wood chip, equivalent to £37.90/odt. The supply chain for forest material is much more complex because this material is currently left in the forest by the forestry contractors. Any system of collection must be integrated with current forest management practices. Prior to use in the CHP plant the material must be chipped to an agreed specification. Two suitable sources of residues for the CHP have been identified as follows:

• •

Material from skyline harvesting operations or integrated harvesting. A percentage of the material from conventional harvesting.

Supply chain options for this material are as follows: • •

Material is chipped in the forest landing and put directly onto transportation vehicles. Material is transported to a centralised chipping facility, from where it would be transported on to the CHP plant.

•

Material is chipped at the landfill site for use in the CHP.

The Forestry Contracting Association (Ref 38), following detailed contacts with Forest owners, managers and contractors, has estimated the total potential GB wood fuel resource at 308,639 odt per annum. However this potential resource is reduced by the need to produce material of a suitable quality for use in the wood fuelled CHP. Factors affecting this are the source of the residue, type of chipping / screening, and the costs of processing. The amount suitable for CHP brings the annual resource potential of the forest down to a GB total of 139,618 odt with Scotland 82,808 odt, Wales 28,149 odt and England 28,661 odt. The choice of the most cost effective supply chain for wood fuel from forest residues will depend on the economic analysis. The overall supply chain in the interim period will depend on the relative cost of purchasing material from sawmills or from forest sources. The cost of fuelling the plant from sawmill wood chips has been established and is unlikely to vary according to size.

6.3.

Markets for Wood Fuelled CHP

Markets currently exist for the energy produced from renewable resources, both for electricity and thermal energy (heat). A successful project will obtain the best overall energy efficiency. Electricity can be transported over long distances without significant energy losses when compared to heating pipeworks. A wood fuelled CHP unit is therefore best located as close as possible to a heat user. A CHP unit should also be sited within reasonable proximity to the fuel source but not necessarily at a landfill site or adjacent to the SRC plantations.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 29

6. Work Package Three

For electricity generated from renewable sources the marketing decision making process is complicated by the support mechanisms put in place by government to promote development of renewable energy resources, as well as the introduction from April 2001 of the Climate Change Levy [Ref 24] [Note 5]. The government’s support is changing from the Non Fossil Fuel Obligation (with Scottish and Northern Irish equivalents) to the Renewables Obligation (RO) [Ref 25, 26] [Note 6]. However the basic options are the generation of renewable energy either for use within one’s own organisation or for sale to third parties [Ref 27, 28]. The RO is an obligation placed on licensed Public Electricity Suppliers (PES) to supply a specified proportion of their electricity supplies to customers from renewable sources of energy. As an alternative to supplying renewable electricity, suppliers can buy out their obligation at a fixed price that is likely to be 3 pence per kWh [Note 7] and will be the same across Great Britain. The Northern Ireland situation is that the NFFO system has not yet been replaced and development of a Renewables Obligation will depend on the Northern Ireland Legislative Assembly [Ref 26]. There will be a number of additional opportunities arising from trading of “Green Certificates”. However the trading options for electricity are: • • • • • •

Sale through the NETA trading mechanisms [Note 8] [Ref 28]. Sale to the Public Electricity Supplier. Sale through a Renewables Obligation. Sale to a second tier supplier. Direct sales to a customer or group of customers. Sale as an on site generator.

In addition the green trading options are: •

Sale of Renewables Obligation Certificates (ROCs), which can be traded independently of the electricity supplied.

•

Sale of Levy Exemption Certificates (LECs), which cannot be traded independently of the electricity supplied.

The greatest economic and environmental benefits accrue to projects where there is a requirement for heat. Irrespective of the eventual capacity of the CHP unit chosen it will have an associated heat output approximately equal to the electrical output. For example a 1200 kWe unit would have an output of 1200 kWth. [Note 9]. Locating the plant near a heat user avoids dumping of heat or lengthy pipework/pumping systems to convey the heat. The markets for thermal energy are: •

Industrial process heating, including on site usage; eg: at a landfill site by improving leachate treatment through heating or for office heating [Ref 29].

•

District heating for buildings or commercial loads

•

Absorption refrigeration plants.

6.4.

Project Economic Evaluation

As has been shown earlier, in order for a landfill site to comply with current and future EC Directives the amount of BMW going to landfill must be reduced substantially. It has also been shown that various feedstocks and sorting methods available for providing BMW, and that various technologies are available for producing compost from this BMW. There are then a number of potential uses for the compost produced, such as general landscaping, amenity grounds maintenance, gardening and horticulture. To simplify the economic analysis it will be assumed that the landfill operator has selected the most appropriate BMW feedstock and compost production facility for his landfill site in order to comply with EC Directives. It is assumed that the avoided landfill disposal costs and the avoided landfill tax will be used by the landfill site operator to finance the construction of the BMW feedstock treatment and compost production facility. This will allow the compost to be made available at zero cost to a potential user. It is then a question of what to do with the compost that has been produced. This economic analysis will therefore provide the landfill operator with the information he needs to assess the economic feasibility of using this compost on landfill sites and other brownfield sites for production of SRC, which can then be used to generate renewable energy

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 30

6. Work Package Three

using B9 Energy’s biomass gasification CHP unit.

6.4.1. Project Concept Economic Model In order to evaluate the economic viability of the project concept an Excel® spreadsheet model was developed. This spreadsheet considered the following elements: • Capital expenditure i.e.: those costs relating to setting up the project, for example purchasing of the CHP unit and the leachate recycle system. • Annual expenditure i.e.: those costs relating to the operation of the project, for example expenditure on operating and maintenance costs, rates and insurance costs, consumable items, waste disposal costs and any additional wood supplies that are required. • Annual income i.e.: income generated by the project from the sale of its products, and from avoided costs e.g.: electricity sales, heat sales, avoided leachate treatment and land remediation costs. The use of this economic model allows the projected income and expenditure to be analysed on an annual basis, which coupled to information on the capital costs, permits project paybacks, return on investment (ROI) and internal rates of return (IRR) to be calculated. Such criteria are well established within the financial sector as project investment decision tools. It should be noted that the systems analysed in this report are based on the best available information provided by the project partners. However, they will vary from site to site and each individual project must be evaluated on its own merits and real life operating and capital costs included for any specific project economic/financial appraisal.

6.5. Conceptual Systems Analysed As detailed in section 4.2.2, two different sized landfill site case studies were analysed, a large scale site taking 400,000 t/yr MSW and 40,000 t/yr green waste and a small scale site taking 120,000 t/yr MSW and 30,000 t/yr green waste. For each size of site two different compost conversion rates were analysed, a high conversion rate and a low conversion rate. This therefore produces four different scenarios, large scale-high conversion, large scale-low conversion, small scale-high conversion and small scale-low conversion. For each scenario a series of sensitivity studies was performed.

6.5.1. Large Scale-High Conversion Scenario The following assumptions are made for the large scale high conversion scenario: • The volume of MSW sent to landfill is 400,000 t/year. • The volume of green waste sent to landfill is 40,000 t/year. • Sorting of the MSW plus loss of moisture during composting means that in effect 30% of the MSW is converted to compost. • Sorting of the green waste plus loss of moisture during composting means that in effect 50% of the green waste is converted to compost. • A total bunded landfill area of 48 hectares is available suitable for growing SRC. • A sufficient area of brown field sites requiring remediation is available within the vicinity to use the surplus compost. • Sufficient agricultural land is available within the vicinity to produce any addition wood chips required. Forestry material is also available if required. • A suitably sized B9 Energy wood-fuelled CHP unit is located near to the composting site and heat is sold to a local company at 1.8 p/kWh, electricity is sold directly to the local council at 6 p/kWh. • SRC is established within the landfill area, and adjacent areas at a cost of £1760 per hectare, the associated management cost is assumed to be £300 ha/year.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 31

6. Work Package Three

• Any additional wood fuel may be purchased off site at £40/odt. • The cost of leachate treatment is 32p per tonne, and 1400 t/ha of leachate can be recycled back to the SRC (landfill) plantations during the growing season. • The compost is blended at a ratio of 50:50 with the soil already existing on the site to achieve a depth of 30cm in which to plant the SRC (15cm compost). • Following harvesting a dressing of 16cm of compost is applied to the SRC. The same compost depths are used in the remediation of nearby brownfield sites. • Remediation costs of £15,000 per hectare for landfill and brownfield sites. • All of the compost will be used to produce SRC. • SRC yield on the landfill is 6 odt/ha/year and for plantations off site it is 8 odt/ha/year. • A spreading cost of 50p/t of compost is assumed. • A leachate recycling system is included within the landfill bunded area at a capital cost of £2000/ha. Consumables are estimated at £2000/year including the pumping costs for leachate spreading. Annual manpower to maintain the system is estimated at £10,000. • The tax rate is 20%. • No grant aid support is available to the project. • Rates and insurance are assumed at 1.0% of the capital cost. The results from this scenario show a total of 140,000 t/year of compost is produced. This is spread on the 48 hectares of the landfill site and an additional 470 hectares of brownfield site to ensure a continuous market for the compost produced by the project. Over the 15 years of the project a total of 44,500 tonnes of SRC is produced, which together with 16,000 tonnes of additional off-site wood fuel is sufficient to supply a 750kWe CHP unit. Most of this additional off-site wood is required during the first four years of the project until the SRC crop is ready for harvesting. The profit and loss account shows an average profit from the CHP unit of £286,500/yr, a loss of £86,000/yr from recycling leachate, an average profit of £520,000/yr from avoided landfill remediation costs, an average cost of £215,000/yr for SRC production and £44,000/yr for off-site wood purchases. This equates to an average profit of £460,000/yr for the 15 years of the project. The total capital cost for the CHP unit and leachate recycle plant is just under £1M, giving a simple payback period of 2.2 years and a ROI of 45%. The cash flow situation is quite complicated in that the main revenue stream, the avoided remediation cost, is realised in the first three years. This gives a very positive cash flow situation for the first three years. However, for the remainder of the project the cash flow situation is negative because the leachate recycle, SRC production and off-site wood purchase costs are higher than the income from the CHP unit. The IRR is calculated at 193%, which reflects the effect of large positive cash flows at the start of the project and small negative cash flows at the end of the project. Emissions savings over the project lifetime are estimated as follows. CO2 CH4 NO2 SOx

90,000 tonnes 382,000 tonnes -93 tonnes 1,100 tonnes

The savings generated from a reduction in CO2 emissions equate to 34 million litres of diesel.

6.5.2. Large Scale-Low Conversion Scenario The same assumptions are made for the landfill site as in the previous scenario except that in this case it is assumed that the composition of waste going to the landfill site gives a low conversion rate of MSW to compost (10%) and of greenwaste to compost (30%). The results from this scenario show a total of 52,000 t/year of compost is produced. This is spread on the 48 hectares of the landfill site and an additional 144 hectares of brownfield site

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 32

6. Work Package Three

to ensure a continuous market for the compost produced by the project. Over the 15 years of the project a total of 15,800 tonnes of SRC is produced, which together with 8,500 tonnes of additional off-site wood fuel is sufficient to supply a 300kWe CHP unit. Again, most of this additional off-site wood is required during the first four years of the project until the SRC crop is ready for harvesting. The profit and loss account shows an average profit from the CHP unit of £114,000/yr, a loss of £86,000/yr from recycling leachate, an average profit of £192,000/yr from avoided landfill remediation costs, an average cost of £80,000/yr for SRC production and £23,000/yr for off-site wood purchases. This equates to an average profit of £118,000/yr for the 15 years of the project. The total capital cost for the CHP unit and leachate recycle plant is just under £0.5M, giving a simple payback period of 4.3 years and a ROI of 23.3%. Again, the cash flow situation is complicated as the main revenue stream, the avoided remediation cost, is realised in the first three years. This gives a very positive cash flow situation for the first three years. However, for the remainder of the project the cash flow situation is negative because the leachate recycle, SRC production and off-site wood purchase costs are higher than the income from the CHP unit. The IRR is not calculable in this situation. Emissions savings over the project lifetime are estimated as follows. CO2 CH4 NO2 SOx

36,000 tonnes 142,000 tonnes -37 tonnes 440 tonnes

The savings generated from a reduction in CO2 emissions equate to 13.5 million litres of diesel.

6.5.3. Small Scale-High Conversion Scenario The following assumptions are made for the small scale scenarios: • Typical annual MSW waste landfilled is 120,000 t/year. • Typical green waste landfilled is 30,000 t/year. • Total mass of waste landfilled is 150,000 t/year. • Sorting of the MSW plus loss of moisture during composting means that in effect 30% of the MSW is converted to compost. • Sorting of the green waste plus loss of moisture during composting means that in effect 50% of the green waste is converted to compost. • A total bunded landfill area of 178 hectares is available suitable for growing SRC. • A sufficient area of brown field sites requiring remediation is available within the vicinity to use surplus compost. • Sufficient agricultural land is available within the vicinity to produce any additional SRC required. Forestry material is also available. • A suitably sized CHP unit is located near to the composting site and heat is sold to a local company at 1.8 p/kWh, electricity is sold directly to the local council at 6 p/kWh. • SRC is established within the landfill area, and adjacent areas at a cost of £1760 per hectare, the associated management cost is assumed to be £300 ha/year. • Any additional wood fuel may be purchased off site at £40/odt. • The cost of leachate treatment is 32p/t, and 1400 t/ha of leachate can be recycled back to the SRC (landfill) plantations during the growing season. • The compost is blended at a ratio of 50:50 with the soil already existing on the site to achieve a depth of 30cm in which to plant the SRC (15cm compost). • Following harvesting a dressing of 16cm of compost is applied to the SRC. The same compost depths are used in the remediation of nearby brownfield sites.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 33

6. Work Package Three

• Remediation costs of £15,000/ha for landfill and brownfield sites. • All of the compost is used to produce SRC. • SRC yield on the landfill is 6 odt/ha/year and for plantations off site it is 8 odt/ha/year. • A spreading cost of 50p/t of compost is assumed. • A leachate recycling system is included within the landfill bunded area at a capital cost of £2000 per hectare. Consumables are estimated at £2000/year including the pumping costs for leachate spreading. Annual manpower to maintain the system is estimated at £10,000. • The tax rate is 20%. • No grant aid support is available to the project. • Rates and insurance are assumed at 1.0% of the capital cost. The results from this scenario show a total of 51,000 t/year of compost is produced. This is spread on the 178 hectares of the landfill site and an additional 10 hectares of brownfield site to ensure a continuous market for the compost produced by the project. Over the 15 years of the project a total of 12,600 tonnes of SRC is produced, which together with 8,500 tonnes of additional off-site wood fuel is sufficient to supply a 260kWe CHP unit. Again, most of this additional off-site wood is required during the first four years of the project until the SRC crop is ready for harvesting. The profit and loss account shows an average profit from the CHP unit of £95,000/yr, a loss of £292,000/yr from recycling leachate, an average profit of £188,000/yr from avoided landfill remediation costs, an average cost of £78,000/yr for SRC production and £23,000/yr for off-site wood purchases. This equates to an average loss of £109,000/yr for the 15 years of the project. The total capital cost for the CHP unit and leachate recycle plant is just over £0.72M. This scenario is adversely affected by both the operating cost (£292,000/yr) and the capital cost (£356,000) of the leachate recycle system. One way for this scenario to give a pay back period of less than 5 years would be if a fee of £5/tonne of compost used was available. Emissions savings over the project lifetime are estimated as follows. CO2 CH4 NO2 SOx

31,000 tonnes 139,000 tonnes -32 tonnes 384 tonnes

The savings generated from a reduction in CO2 emissions equate to 11.7 million litres of diesel.

6.5.4. Small Scale-Low Conversion Scenario The same assumptions are made for the landfill site as in the previous scenario except that in this case it is assumed that the composition of waste going to the landfill site allows a low conversion rate of MSW to compost (10%) and of greenwaste to compost (30%). The results from this scenario show a total of 21,000 t/year of compost is produced. This is spread on 77 hectares of the landfill site and no additional brownfield sites are required. Over the 15 years of the project a total of 5,100 tonnes of SRC is produced, which together with 5,500 tonnes of additional off-site wood fuel is sufficient to supply a 130kWe CHP unit. A higher proportion of additional off-site wood is required for this scenario because this is the smallest size of CHP unit that can be specified. The profit and loss account shows an average profit from the CHP unit of £47,000/yr, a loss of £131,000/yr from recycling leachate, an average profit of £77,000/yr from avoided landfill remediation costs, an average cost of £32,000/yr for SRC production and £15,000/yr for off-site wood purchases. This equates to an average loss of £54,000/yr for the 15 years of the project. The total capital cost for the CHP unit and leachate recycle plant is just under £0.4M. Again, this scenario is adversely affected by both the operating cost (£131,000/yr) and the capital cost (£154,000) of the leachate recycle system. One way for this scenario to give a pay back period of less than 5 years would be if a fee of £7/tonne of compost used was available.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 34

6. Work Package Three

Emissions savings over the project lifetime are estimated as follows. CO2 CH4 NO2 SOx

16,000 tonnes 57,000 tonnes -16 tonnes 192 tonnes

The savings generated from a reduction in CO2 emissions equate to 5.8 million litres of diesel.

6.6 Discussion of Results From the results presented above a clear picture emerges with regard to the economic viability of using compost on landfill sites and other brownfield sites for production of SRC, which can then be used to generate renewable energy using B9 Energy’s biomass gasification CHP unit. The important income generation streams are the avoided remediation costs for the landfill and brown field sites and the sales of heat and electricity. The important expenditure streams are the leachate recycle system, the cost of producing the SRC and the cost of purchasing the additional off-site wood required. The total area of landfill and brown field sites used depends directly on the compost available. Therefore the large landfill site with a high conversion rate produces 140,000 tonnes/yr compost and requires 518 hectares of land, whereas the small site with a low conversion rate produces only 21,000 tonnes/yr compost and requires 77 hectares. The large landfill site with a low conversion rate and the small site with a high conversion rate both produce about 52,000 tonnes/yr compost and require similar areas of about 190 hectares. The sales of electricity and heat depend on the size of the CHP unit. In these scenarios the CHP unit has been sized to use all of the SRC produced while minimising the amount of off-site wood purchased. However, the cost of the SRC is higher than the cost of off-site wood. SRC produced on the landfill site costs £94.3/dry tonne and SRC on brown field sites costs £70/dry tonne compared with an assumed off-site wood cost of £40/dry tonne. This cost includes the annual SRC management cost and the compost spreading cost, but does not include the one-off establishment costs. Therefore, on a case by case basis the size of CHP unit and quantity of off-site wood purchased should be reviewed in light of the availability of low cost off-site wood, such as SRC grown on agricultural land or waste wood recovered from MSW. Increasing the size of the CHP plant has a small positive effect on the project payback period, ROI and IRR. Although SRC as a fuel is more expensive than purchasing wood from off-site sources it should not be forgotten that SRC is the catalyst for the system, and provides the outlet for the compost in the form of a growing medium. The value therefore attached to the SRC is not just an economic one related to its production cost but also as a medium via which waste derived compost can be used. The final impact on the project viability is the leachate recycle system. While there is a saving in leachate treatment costs this is substantially less than the consumables and manpower costs involved with operating the leachate recycle system. The volume of leachate that is recycled depends on the area of the landfill site, and therefore the small scale sites, which have a large landfill area suffer the most from this. For example the small scale high conversion scenario is adversely affected by both the net operating cost (£292,000/yr) and the capital cost (£356,000) of the leachate recycle system. This reflects the large area of the landfill site in relation to the MSW processed. Without leachate recycle this scenario would give an average profit of £186,000/yr, a simple payback period of 2.1 years and an ROI of 48.4%. It should also be remembered that it is assumed that leachate recycle does not produce any additional SRC yield. The use of leachate to promote SRC growth is not quantifiable as the influence of leachate on SRC yield is not known. The use of recycling of leachate within the current model is worth considering either where a complete new landfill site is being built, or where an expansion of existing facilities is required. A deferred / saving in capital investment is therefore required as the savings in treatment costs alone cannot justify the additional consumables required for such a system. An additional income, in the form of a fee for using the compost, would have a large positive impact on all of these scenarios. In particular for the small scale high conversion scenario a pay back period of less than 5 years is possible if a fee of £5/tonne of compost used was available. Likewise, for the small scale low conversion scenario a pay back period of less than 5 years is possible if a fee of £7/tonne of compost used was available.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 35

6. Work Package Three

Where significant changes in activities are foreseen at a landfill site e.g. with the introduction of an MSW pretreatment and composing facility, significant change will occur in the overheads. The effect of composting on landfill site operating overheads is an area that needs further investigation. The waste diversion rates and savings in emissions with the above scenarios serve to demonstrate that the project concept could have a key role to play in future waste management strategies and in meeting global emission reduction targets.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 36

7. Demonstration project

7.0 Demonstration Project Individual components of the project concept have been demonstrated to some degree within the UK, for example energy generation from SRC, composting integrated with landfill site. However, an integrated project based on this concept would be the first project of its kind in the World and would demonstrate the following four techniques: •

Composting waste to form a growing medium.

•

Growing SRC in compost on top of the landfill cap and reapplying compost for weed control.

•

Use of leachate to improve crop yield.

•

Installation of a wood gas CHP fuelled by SRC grown on the land fill site and surrounding area.

A practical demonstration as to the technical feasibility and economic viability of the concepts would be the focus of great interest for both landfill operators and the wider environmental community.

7.1 Project Justification The use of renewable resources such as biomass, which are naturally and continuously re-created, coupled with reuse of biodegradable materials to enhance soils can only assist sustainability as well as helping the UK meet its own and EU targets for renewables and waste. A number of benefits accrue from the integration of wood fuelled CHP and landfill and include: • Diversification of energy supplies and their uses • Development of biomass industry potential • Environmental impact of compost based soil production - Composting results in the evolution of CO2 as opposed to methane, which is 21 times less potent in terms of the greenhouse effect than methane - Replacement of fossil fuels and substitution of CO2 for methane will help towards meeting the UK’s international targets. - The diversion of materials from landfill will help meet the EU Waste Directive’s targets. - The return of organic matter to soils from composted materials could help to mitigate the effects of a regime of high external nutrient inputs to agricultural land over many years. • Reduction of materials landfilled giving increased life of landfill site - A reduction in the proportion of wastes going into landfill either results in an increased life for the landfill site or, if the life duration is fixed, the capacity to landfill at a greater rate. - In either case a landfill/SRC/CHP project could defer investment in new landfill sites. • Diversion of waste from landfill to compost based soil production. - Organic waste diverted from landfill and used to produce compost-based soil would not be subject to Landfill Tax. • Increased amenity value - Growing SRC at landfill sites would greatly improve neighbourliness and the visual perspectives of the site as well as avoiding the costs of landscaping by the landfill operator. - Remediation of derelict land or brownfield sites would provide benefits to localities and take pressure off greenbelts for development. • Increased biodiversity - Willow supports the greatest number of species of fauna of all native species and a stable, diverse ground flora, which helps to preserve the moisture and integrity of the soil [Ref 32 & 33]

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 37

7. Demonstration project

Increased employment •

Additional employment would be created/maintained for manufacturing, constructing, operating and maintaining the CHP unit, the composting facilities, the SRC plantations and for material handling/transporting. The levels of employment will of course be dependent on the size of the facilities For the large scale case study an estimated 90 jobs would be created with 30 in the small scale case study. The majority of the jobs created will be in the waste handling, segregation and operation of the composting facilities. Employment opportunities will also be created in operation and maintenance of the CHP unit and in the forestry and agricultural sectors in planting and harvesting of the fuel. The procurement of local supplies and employment of labour, coupled with the multiplier effect will result in a significant amount of expenditure in the local economy.

• Enhanced Rural Development - The project concept would provide opportunities for diversification of current agricultural practices, retention of people in the rural economy, skills enhancement and new or continued local employment.

7.2 Project Implementation and Operating Timeframe Design lifetime of a CHP plant is 20 years. A similar lifetime would be anticipated for the composting facilities. SRC production has the highest potential longevity at up to 25 to 30 years. Attached is a simplified indicative project programme from the beginning of year 0, the start of development, up to the end of year 5. Harvesting will then take place every year on each 1/3 of the SRC plantation in sequence. Project development is shown in year 0 but in practice this period is not determinate. • The installation of the CHP and composting plants are shown taking place during year 1. • The SRC plantation is highly dependent on a planting deadline for the willow cuttings and planting is shown as 1/3 at a time over 3 successive years, commencing in year 2. - For the first 1/3 cutting back is shown one year after initial planting in year 3 with its first harvest and mulching 3 years later in year 6. - The second and third 1/3 plantings will take place in years 3 and 4 with harvesting/mulching in years 7 and 8 respectively. - In practice the SRC preparation and planting programme will depend on the actual site layout and access to capped landfill cells or other land. • Planting is also dependent on sufficient compost being available and the site being prepared the autumn/winter before. • For example production of compost for the first 1/3 of the SRC plantation is shown as taking place at the end of year 1 after construction of the composting plant. The composting plant must have sufficient capacity to provide this amount of compost. • As shown there is a pause between year 3’s compost production for the final 1/3 planting in year 4 and production for mulching after the first 1/3 harvest in year 6, an alternative outlet for the compost must be found during this period of time.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 38

**

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 39

*

Harvest

Mulch

The size of the compost plant is also critical to the timing of thr establishment of the first 1/3 of the SRC Plantation in that there must be sufficient capacity to provide the amount of compost required for soil creation.

Cut back

Mulch

**

Cut back

Harvest

The establishment of the first 1/3 of the SRC lantation is constrained by the need to plant the willow cuttings in the Spring with early May the latest that reasonable success can be expected.

Cut back

J A S O N D

YEAR 7

J A S O N D J F M A M J

YEAR 6

J A S O N D J F M A M J

YEAR 5

J A S O N D J F M A M J

YEAR 4

J A S O N D J F M A M J

YEAR 3

J A S O N D J F M A M J

YEAR 2

J A S O N D J F M A M J

YEAR 1

J A S O N D J F M A M J

YEAR 0

J F M A M J

*

Harvest & mulch (not shown)

Prepare site, plant & cut back

SRC Third 1/3 plantation

Harvest & mulch

Prepare site, plant & cut back

SRC Second 1/3 plantation

Harvest & mulch

Prepare site, plant & cut back

SRC First 1/3 plantation

CHP business management

CHP Operational control

Fuel and ash handling

CHP Operation

Third 1/3 mulching

Second 1/3 mulching

First 1/3 mulching

Third 1/3 planting

Second 1/3 planting

First 1/3 planting

Compost Production for:

System construction as required

Leachate Treatment

Design, build, commission

Compost plant production

Design, build, commission

CHP Production

Place construction contracts

Specifications & tendering

Planning & consultation

Assessment feasability

Project Development

ACTIVITY

Biomass Integration with landfill Indicative project schedule

7. Demonstration project

8. Conclusions & Recommendations

8. Conclusions and Recommendations This study has shown that it is potentially technically and economically feasible to use compost produced from biodegradable municipal waste (BMW) to grow biomass for use in combined heat and power (CHP). This could be achieved by an integrated cross-sectoral approach, between agriculture, energy and waste industries. In addition, this approach could also be followed for the remediation of brownfield sites. There are clear economic, social and environmental benefits that could be achieved, while meeting the new and growing legislative requirements for dealing with wastes and increasing the use of renewable energy. Compost production in the UK will have to increase rapidly to meet EU and UK targets for reduction of BMW going to landfill. Provided that compost quality standards can be established and achieved, and agreement reached to allow waste derived compost to be used as a growing medium on landfill caps, then compost could be used as a growing medium and top dressing for SRC willow plantations on capped landfill or brownfield site remediation. SRC willow could be successfully grown on capped landfill and adjacent agricultural land provided that existing soils can incorporate compost to give a suitable growing medium and that there is sufficient or excess water available during the growing season. Water and plant nutrients could be partly provided by landfill leachate, while other nutrients could be provided after harvest or by a top dressing or mulch of compost. Top dressing could also act as a weed suppressant. Appropriate technology exits for combined heat and power production from SRC willow, and again renewable energy production will have to increase significantly if the UK and EU targets are to be are to be met. There are many markets for the sale of renewable energy, particularly electricity, and a number of models exist for this. Indeed government support provides a premium in the form of a Renewable Obligation on Public Electricity Suppliers to provide a proportion of electricity from renewable sources. The energy project economic and environmental benefits would be maximised if either the CHP unit were situated remotely from the landfill at the heat load, for example a new housing or industrial development, or a sufficient heat load existed at the landfill site. This feasibility study investigated the case of both large and small scale landfill sites, with both high and low MSW and green waste to compost conversion rates. It also assessed the potential impact on emissions and waste diversion. •

For the large-scale high conversion rate scenario 140,000 t/year of compost is produced and spread on the 48 hectares of the landfill site and an additional 470 hectares of brown field site. Over the 15 years of the project a total of 44,500 tonnes of SRC is produced, which together with 16,000 tonnes of additional off-site wood fuel is sufficient to supply a 750kWe CHP unit. The profit and loss account shows an average profit of £460,000/yr for the 15 years of the project. The total capital cost for the CHP unit and leachate recycle plant is just under £1M, giving a simple payback period of 2.2 years and a ROI of 45%. The cash flow situation is quite complicated in that the main revenue stream, the avoided remediation cost, is realised in the first three years. This gives a very positive cash flow situation for the first three years.

•

However, for the remainder of the project the cash flow situation is negative because the leachate recycle, SRC production and off-site wood purchase costs are higher than the income from the CHP unit. Emissions savings over the project lifetime are 90,000 tonnes CO2 , 382,000 tonnes CH4 , -93 tonnes NO2 , 1,100 tonnes SOx . The savings generated from a reduction in CO2 emissions equate to 34 million litres of diesel.

•

For the large-scale low conversion rate scenario a total of 52,000 t/year of compost is produced and spread on the 48 hectares of the landfill site and an additional 144 hectares of brownfield site. Over the 15 years of the project a total of 15,800 tonnes of SRC is produced, which together with 8,500 tonnes of additional off-site wood fuel is sufficient to supply a 300kWe CHP unit. The average profit is £118,000/yr for the 15 years of the project and the total capital cost for the CHP unit and leachate recycle plant is just under £0.5M, giving a simple payback period of 4.3 years and a ROI of 23.3%. Emissions savings over the project lifetime are 36,000 tonnes CO2 , 142,000 tonnes CH4, -37 tonnes NO2, 440 tonnes SOx. The savings generated from a reduction in CO2 emissions equate to 13.5 million litres of diesel.

•

For the small-scale high conversion rate scenario 51,000 t/year of compost is produced and spread on the 178 hectares of the landfill site and an additional 10 hectares of brownfield site. Over the 15 years of the project a total of 12,600 tonnes of SRC is produced, which together with 8,500 tonnes of additional off-site wood fuel is sufficient to supply a 260kWe CHP unit. The profit and loss account shows an average loss of £109,000/yr for the 15 years of the project. The total capital cost for the CHP unit and leachate recycle plant is just over £0.72M. This scenario is adversely affected by both the operating cost (£292,000/yr) and the capital cost (£356,000) of the leachate recycle system. Emissions savings over the project lifetime are 31,000 tonnes CO2 , 139,000 tonnes CH4, -32 tonnes NO2 , 384 tonnes SOx. The savings generated from a reduction in CO2 emissions equate to 11.7 million litres of diesel.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 40

8. Conclusions & Recommendations

• For the small-scale low conversion rate scenario 21,000 t/year of compost is produced and spread on 77 hectares of the landfill site with no additional brownfield sites required. Over the 15 years of the project a total of 5,100 tonnes of SRC is produced, which together with 5,500 tonnes of additional off-site wood fuel is sufficient to supply a 130kWe CHP unit. A higher proportion of additional off-site wood is required for this scenario because this is the smallest size of CHP unit that can be specified. The profit and loss account shows an average loss of £54,000/yr for the 15 years of the project. The total capital cost for the CHP unit and leachate recycle plant is just under £0.4M. Again, this scenario is adversely affected by both the operating cost (£131,000/yr) and the capital cost (£154,000) of the leachate recycle system. Emissions savings over the project lifetime are 16,000 tonnes CO2, 57,000 tonnes CH4, -16 tonnes NO2 , 192 tonnes SOx. The savings generated from a reduction in CO2 emissions equate to 5.8 million litres of diesel. From the results presented above a clear picture emerges with regard to the economic viability of this concept. The important income generation streams are the avoided remediation costs and the sales of heat and electricity. The important expenditure streams are the leachate recycle system, the cost of producing the SRC and the cost of purchasing the additional off-site wood required. The total area that can be remediated depends directly on the compost available and therefore directly on the scale of the landfill site and the conversion rate of MSW and green waste to compost. The large scale site with a high conversion rate requires 518 hectares of land, whereas the small scale site with a low conversion rate requires only 77 hectares. The sales of electricity and heat depend on the size of the CHP unit. In these scenarios the CHP unit has been sized to use all of the SRC produced while minimising the amount of off-site wood purchased. However, the cost of SRC produced on the landfill site is £94.3/dry tonne and on brown field sites is £70/dry tonne compared with an assumed off-site wood cost of £40/dry tonne. Therefore, on a case by case basis the size of CHP unit and quantity of off-site wood purchased should be reviewed in light of the availability of low cost off-site wood, such as SRC grown on agricultural land or waste wood recovered from MSW. Increasing the size of the CHP plant has a small positive effect on the project payback period, ROI and IRR. Although SRC as a fuel is more expensive than purchasing wood from off-site sources it should not be forgotten that SRC is the catalyst for the system, and provides the outlet for the compost in the form of a growing medium. The value therefore attached to the SRC is not just an economic one related to its production cost but also as a medium via which waste derived compost can be used. The final impact on the project viability is the leachate recycle system. While there is a saving in leachate treatment costs this is substantially less than the consumables and manpower costs involved with operating the leachate recycle system. The volume of leachate that is recycled depends on the area of the landfill site, and therefore the small scale sites, which have a large landfill area suffer the most from this. It has been assumed that leachate recycle does not produce any additional SRC yield. The use of recycling of leachate within the current model is worth considering either where a complete new landfill site is being built, or where an expansion of existing facilities is required. An additional income, in the form of a fee for using the compost, would have a large positive impact on all of these scenarios. In particular for the small scale scenarios a pay back period of less than 5 years is possible if a fee of £5-£7/tonne of compost used was available. Where significant changes in activities are foreseen at a landfill site e.g. with the introduction of an MSW pretreatment and composing facility, significant change will occur in the overheads. The effect of composting on landfill site operating overheads is an area that needs further investigation. The waste diversion rates and savings in emissions with the above scenarios serve to demonstrate that the project concept could have a key role to play in future waste management strategies and in meeting global emission reduction targets. The development and establishment of such an integrated waste/biomass project would give practical demonstration as to the feasibility and viability of the concepts. Integration of the project concept is achievable on a scale consistent with the size of both large and small landfill operations. Successful project delivery will depend on the developers putting in place the necessary information to demonstrate that the project will meet the financial/economic, environmental, legislative and regulatory criteria required by the various responsible entities. In terms of project management a cross-sectoral approach is required, including expertise from agriculture, waste and energy sectors. A successful project would also help to improve the image of landfill sites and by implication improve the public perception of landfill companies. Growing willow on capped landfill would greatly improve both neighbourliness and visual perspectives, and the project as a whole could positively impact the local economy through the creation of jobs and inflow of money through the purchase of fuel supplies and services. As with all such projects early attention to PR and consultation with local communities, planners and other regulatory bodies is vital to ensure a broad-based understanding and successful project implementation. As detailed above, benefits would include commercial, environmental, employment and rural economic development, as well as demonstrating that the project would assist in meeting EU and UK targets on waste and renewable energy.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 41

8. Conclusions & Recommendations

A pilot project is needed in order to provide the facilities on which to carry out an overall mass balance of the system, and help further research as detailed below. It is recommended that development of an integrated composting/CHP/SRC pilot project be undertaken at a suitable landfill site to demonstrate the feasibility and practicability of the concepts.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 42

9. Further Research

9. Further Research Work to take the Concept Forward It is recommended that the following research work should be carried out prior to commercialising the concept: • The suitability of waste derived compost and the quality standards appropriate for returning organic matter to soil needs to be further researched. • The potential to use waste derived compost to assist in the establishment of new stands of SRC needs to be evaluated and tested. • Diverting material away from landfill will reduce the amount of landfill gas produced from a landfill site. Further research into the effect of the project concept on reducing methane emissions is desirable. • There is significant potential to provide a continuous outlet for compost in top dressing SRC. Further research is required through field trials to ascertain the long term affects of reapplying such compost to SRC plantations. • Potential exists to improve the yield of SRC through the application of leachate to SRC plantations within the landfill site bunded area. However the potential interactions between leachate and compost and their consequential effect on SRC is not well understood. Further research in this area is required through field trials. • In vessel composting is in its early stages of development within the UK. However, it has great potential to be an environmentally friendly method of processing waste. Further data is required on the capital and operational costs associated with the segregation of waste and large scale composting systems. As more commercial developments are built this information will become more clearly defined and widely available. • Although SRC has been used to fuel biomass CHP technology, integration with landfill is novel and the quality of the SRC fuel and its operation within the CHP unit requires evaluation. • Where composting is implemented as an alternative to landfilling, the site’s overheads will change and need to be allocated accordingly. Further research into the impact on landfill operating costs and overheads is required.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 43

10. Project Dissemination

10. Project Dissemination Dissemination of the project will be undertaken in the third quarter of 2002 by the following: • Publication of a project final report. • Seminars to publicise the project findings. • Press releases to waste management publications. • Publication of the project economic model. The target audience is defined as those who would most likely benefit from such a scheme and who could become actively involved in the practical application of the project. The project is applicable UK wide: • Private sector waste management industry. • Public sector waste management industry. • Organisations responsible for managing ‘brownfield’ sites • The Environment Agencies – SEPA, EA, and the DOE NI. • Representatives of the National Farmers Union (NFU) • Farming and local communities

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 44

11. Limitation of Liability

11. Limitation of Liability The authors have made every effort to ensure the accuracy of the information contained in this report. However, the authors shall not be liable for any direct or indirect damages arising out of the use of the contents of this report. People considering becoming involved in short rotation forestry enterprises should seek professional advice prior to planting or making other investment decisions.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 45

12. Project Management

12. Project Management The project started in April 2001 for a duration of 9 months.

The project partners and areas of contribution are described below: • B9 Energy Biomass Ltd, Debra Jenkins, Peter Kernohan, David Surplus, Dougie Marr, Brian Williams. CHP, technology project economic evaluation, emissions evaluation, integration, overall project management. • Malcolm Dawson, Department of Agricultural Rural Development, short rotation coppice, leachate recycling. • Professor Harry Duncan, University of Glasgow, recycling project dissemination. • Dr John Mullett, Recycling Services Ltd, composting technology and compost as a growing medium. •

Robert Brennan, environmental consultant, liaison with SEPA and Shanks.

The overall work programme was divided into project work packages eg: SRC, composting, CHP etc. and each work package subdivided into tasks for ease of management. During this time a series of meeting were held at differing partner locations (England, Scotland and N.Ireland) so as to enable a better understanding of each partner’s experience and activities and further develop the idea to a workable solution. Interim reports were produced and the overall project management was carried out by Debra Jenkins, of B9 Energy Biomass Ltd.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 46

Appendix A

Appendix A: Notes 1. There are various elements to the Landfill Directive (LFD) and differing timescales. The guidance for the LFD has not yet been published and it is not yet transposed into UK legislation. The Scottish Executive is currently formulating the regulations, which should be available imminently. The current date for starting the implementation of the LFD is July 2002. This will entail the classification of sites and the production of Conditioning Plans. This will also be the date for excluding certain banned wastes, whole tyres and liquids, for example. The LFD imposes a statutory requirement to reduce the landfilled quantities of Biodegradable Municipal Waste (BMW) as follows. BMW is 60% of MSW and the 1995 tonnage is taken as the baseline in order that any growth in waste arising can be accommodated: 2010 - 75% of BMW permitted to landfill 2013 - 50% of BMW permitted to landfill 2020 - 35% of BMW permitted to landfill 2. The concept of global warming potential (GWP) was introduced to allow comparisons of the total cumulative warming effects of different green house gases (GHG) over a specified time period. A GWP is a measure of relative contribution to radiative forcing (see The Science of Climate Change). A 100-year GWP of 21 for CH4 means that each gram of methane (CH4) emitted is considered to have cumulative warming effects over the next 100 years equivalent to emitting 21 grams of CO2. 3 .Action by both Member States and the Community needs to be reinforced if the EU is to succeed in cutting its GHG emissions to 8% below 1990 levels by 2008-2012 as the Kyoto Protocol requires. It is widely recognised that the Convention commitments could only be a first step in the international response to climate change. Climate prediction models show that deeper cuts in emissions will be needed to prevent serious interference with the climate. The Kyoto Protocol, agreed in December 1997, was designed to address this issue. Developed countries agreed to targets that will reduce their overall emissions of a basket of six GHG (carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulphur hexafluoride) by 5.2% below 1990 levels over the period 2008-2012. For the first time these targets will be legally binding, and differentiated between Parties to the Convention. For example, the European Union and its member states agreed to -8%, the United States to –7%, Japan to –6%, Russia and the Ukraine to return to 1990 levels, and Australia was allowed an 8% increase. Under the Kyoto Protocol, the European Union and its member states can agree to meet their commitments jointly. This ‘bubble’ arrangement allows the EU’s target to be redistributed between member states to reflect their national circumstances, requirements for economic growth, and the scope for further emission reductions. In June 1998, under the UK Presidency, environment ministers agreed how the target should be shared out. The UK agreed to reduce its emissions by 12.5%, which will now become its legally binding target under the Kyoto Protocol. Targets for other member states ranged from –21% for Germany and Denmark, to –6% for the Netherlands, +13% for Ireland and +27% for Portugal. 4. 2% growth was determined by the Glasgow & Clyde Valley Waste Strategy Area Group, prior to profiling the waste management options for the area. It was seen as being excessive to adopt a continuation of the current level of growth of 4%, as extensive waste minimisation programmes will be introduced. The 2% figure has been adopted until 2010 and 1% thereafter. The growth rate adopted varies from waste strategy area to area. 5. Climate Change Levy (CCL) exemption for renewables. The CCL was introduced by the Government under the provisions of the Finance Act 2000 and commenced on 1 April 2001. The CCL is charged at the rate of 0.43p/kWh on electricity supplied to non-domestic customers in the United Kingdom, except where negotiated agreements have been made. Electricity from qualifying renewable sources is exempt from the Levy. 6. The Renewables Obligation. The Utilities Act 2000 gives the Secretary of State the power to make an order requiring suppliers to supply a certain percentage of their total sales from renewable sources. This power has been devolved to the Scottish and Northern Irish administrations’ Office of Gas and Electricity Markets (76) August 2001. It is anticipated that there will be two Obligations across Great Britain, one for England and Wales and one for Scotland. It is expected that these two Obligations will be similar, that the percentage target for both will increase year on year, and that most sources of renewable energy will be eligible. It is anticipated that the Obligation will start towards the end of this year, having passed through Parliament, and that it will remain in place until March 2027, giving some long-term and guaranteed stability to the renewables market. OFGEM expects Obligation periods to be a year long, from 1 April to 31 March but the first period of the Obligation is likely to run from the date it comes into force until 31 March 2003. 8. The Renewables Order will set out the buyout price, which is expected to be 3p/kWh until 1st April 2003. OFGEM will then adjust this in line with the RPI and announce the new buyout price each year. Suppliers will be required to pay

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 47

Appendix A

any buyout due to OFGEM by the specified date described above. It is expected that the proceeds from such buying out will be returned to suppliers by OFGEM, according to the amount of eligible renewable electricity, represented by the ROCs, that each supplier presents to discharge the Obligation, compared to the total amount of electricity supplied. There is therefore a strong financial incentive to fulfil the Obligation through presenting ROCs, rather than buying out. If a supplier chooses to buy out part or the entire Obligation, it will not receive any recycling of the buyout funds for the proportion that it has bought out. 8. The New Electricity Trading Arrangements (NETA) were introduced to address some of the fundamental weaknesses of the wholesale electricity trading arrangements under the Electricity Pool of England and Wales (the Pool), introduced in 1990 at the time of privatisation of the electricity industry. 9. Further information on CHP can be found at www.chpclub.com, the Government’s Environment and Energy Helpline on 0800 585794; the Combined Heat and Power Association on 020 7828 4077 or at www.chpa.co.uk. Information on CHP and renewables can be found at www.caddet-re.org or www.greentie.org.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 48

Appendix B

Appendix B: References 1

www.regeneration.dtlr.gov.uk

2

The EU Landfill Directive, 1999. The European Commission.

3

The UK’s Third National Communication under the UN Framework Convention on Climate Change, October 2001. www.defra.gov.uk/environment/climatechange.

4

New and Renewable Energy - Prospects for the 21st Century, May 1999 - Issue 40 DTI New Review. www.dti.gov.uk

5

The National Waste Strategy: England and Wales - 2000 - Stationery Office or on: 0845 7023474; Wales Waste Strategy or Welsh National Assembly’s website. Scotland 1999 - the National Waste Strategy - Scotland or Scottish Parliament’s website. Northern Ireland, 2000 - The Department of the Environment (Northern Ireland) 028 9054 0540.

6

An Introduction to Household Waste Management, 1998. Produced by ETSU for the Department of Trade and Industry, providing information on some of the most common questions asked by members of the public about waste management.

7

The State of Composting 1999, (published) 2001. Results of The Composting Association’s Survey of UK composting facilities and collection systems in 1999.

8

Draft Working Document on the Biological Treatment of Biowaste, 2001. The European Commission.

9

Composting in the European Union, 1997. DHV Environment and Infrastructure Amersfoot, The Netherlands.

10 Peatering Out, Towards a sustainable UK growing media market, 2001. An English Nature and RSPB joint report based on a commissioned research by horticultural consultants Rainbow Wilson Associates, with contributions from Cambridge Recycling Services Ltd and the Composting Association. 11 The National Trust Magazine, pp 34-37 Number 93 Summer 2001. 12 Animals By-Products Order, 1999. Order introduced by DETR in the wake of the BSE crisis. 13 Agency Position on Composting and Health Effects, 2001. Position statement issued by the Environment Agency, effective from 13th August 2001. 14 Implementation of Council Directive 1999/31/EC on the Landfill of Waste, Second Consultation Paper, 2001. Department of Environment, Food and Rural Affairs in partnership with the National Assembly for Wales. 15 Composting of Green Wastes – A State of the Art Review, 2000. Institute of Water and Environment, Cranfield University. 16 The Composting Association Standards of Composts, Working Document, 2000. The Composting Association. 17 The Development of Composting in Germany, 1997. Dr C.E. Gruneklee, Herhof Umwelttechnik. Proceedings of the Orbit Conference, Edited by Prof E.I. Stentiford, Harrogate. 18 CRS 2001, pers. comm. In-vessel Composting Trials, Analysis Results. Cambridge Recycling Services Ltd. 19 Fertilisation of Short Rotation Energy Coppice Using Sewage Sludge, 1995 - ETSU B/W5/00216/REP - Contractor D Riddell-Black 20 Dawson, Malcolm. Northern Ireland Horticulture and Plant Breeding Station, Loughgall (personal communication to J Mullet, 2001) 21 Lissens G. et al (2001) Water Science and Technology Vol 44. No 8. pg 91-102 Solid Waste digestors: process performance and practice for municipal solid waste digestion. 22 Willoughby. 1., and Clay, D. Herbicides for farm woodlands and short rotation coppice. Forestry Commission Field Work 14. 23 Wood fuel supply strategies Volume 1: Report B1176-P1 1990, ETSU, Harwell, Oxfordshire, United Kingdom. Contractor: University of Aberdeen, Department of Forestry Harvesting Unit 24 Statutory Instrument, “The Climate Change Levy (General) Regulations 2001” (S.I. 2001 No. 838). & Procedure for

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 49

Appendix B

climate change levy exemption for generators producing electricity from renewable sources, (69), August 2001. Office of Gas and Electricity Markets. 25 The Utilities Act 2000 - order (Office of Gas and Electricity Markets), 75, August 2001 - The Renewables Obligation. 26 Renewable Energy in Northern Ireland and the GB Renewables Obligation, 10 October, 2001. Michael Harper, B9 Energy Services Ltd. 27 Commercialisation of Small Hydro through Community Participation - ETSU K/BD/00190/REP, 1999 - Part 6 Electricity Trading Options 28 The New Electricity Trading Arrangements (NETA) – Trading Options for Licence Exemptable Generators - Version 1.0 19 January 2001 29 McCabe, Gerry, Shanks - personal comment December 2001. 30 The production and supply of wood as a Fuel from Conventional Forestry. Technology status reports 015: 1995, ETSU, ,Harwell, Oxfordshire, United Kingdom. Contractor: Technical Development Branch, Forestry Commission. 31 Wood fuel from Forestry and Arboriculture, Good Practice Guidelines. ETSU, 1998. Harwell, Oxfordshire, United Kingdom. 32 ETSU Project Summary 382 - The Wildlife Conservation Potential of Short Rotation Coppice, 1995 - Greater detail found in full Contractor’s Report - ETSU B/W5/00277/REP. 33 Ecological Assessment of Short Rotation Coppice, 1999, ETSU B/W5/00216/REP/1. 34 Ecological and Economical Evaluation of Biomass Ash Utilisation - The Swedish Approach, 1997 - A Lundborg, Vattenfall Utveckling AB, Stockholm. 35 Biomass Ash Utilisation in Finland, October 1998, August 1998 - A Korpilahti, M Moilanen and L Finer. 36 Facts and Figures 1999-2000. Forestry Commission, 2000. Forestry Commission, Edinburgh, United Kingdom 37 Forestry Commission, 1998. Forestry Industry Handbook, 1998. Forestry Commission, Edinburgh, United Kingdom. 38 Forestry Contracting Association, 2001. Personal communications with D. Jenkins, B9 Energy Biomass Ltd.

B9 Energy Biomass Ltd / Entrust Project 760828.044

PAGE 50