Learn About Energy

Let’s learn about energy A practical handbook for teachers

BELARUS

MOLDOVA UKRAINE RUSSIAN FEDERATION

GEORGIA ARMENIA KAZAKHSTAN

AZERBAIJAN MONGOLIA UZBEKISTAN TURKMENISTAN

KYRGYZSTAN

TAJIKISTAN

Let’s learn about energy A practical handbook for teachers

Edited by the Tacis Technical Dissemination Project Published by the European Commission

Published in October 1997 © European Communities, 1997 ISBN 92-828-1966-3 All rights reserved. This publication may only be reproduced, distributed or transmitted, in any form, with the prior permission in writing of the European Commission, Directorate General IA, Tacis. Enquiries concerning reproduction should be sent to the Tacis Information Office, European Commission, Montoyerstraat 34 3/88 Rue Montoyer, B -1000 Brussels. The findings, conclusions and interpretations expressed in this document should in no way be taken to reflect the policies or opinions of the European Commission.

3

Table of contents

What is Tacis?

5

Foreword

6

Introduction

7

Why energy is important

9

Main themes Key information Suggested activities Sources of energy

14

Fossil fuels

15

Main themes Key information Oil Natural gas Coal Suggested activities Nuclear power

25

Main themes Key information Suggested activities Renewable energy

30

Main themes Key information Solar energy Wind Biomass Water power Geothermal Suggested activities Electricity Main themes Key information Suggested activities

41

4

Table of contents

Reducing our energy use

45

Main themes Key information In the home Transport Suggested activities Energy in NIS countries

51

Main themes Key information Suggested activities Glossary

54

List of NIS addresses for enquiries concerning TDP publications

56

Questionnaire

57

5

What is Tacis ?

The Tacis Programme is a European Union initiative for the New Independent States and Mongolia which fosters the development of harmonious and prosperous economic and political links between the European Union and these partner countries. Its aim is to support the partner countries’ initiatives to develop societies based on political freedom and economic prosperity. Tacis does this by providing grant finance for know-how to support the process of transformation to market economies and democratic societies. In its first five years of operation, 1991-1995, Tacis has committed ECU 2,268 million to launch more than 2,200 projects. Tacis works closely with the partner countries to determine how funds should be spent. This ensures that Tacis funding is relevant to each country’s own reform policies and priorities. A part of broader international effort, Tacis also works closely with other donors and international organisations. Tacis provides know-how from a wide range of public and private organisations which allows experience of market economies and democracies to be combined with local knowledge and skills. This know-how is delivered by providing policy advice, consultancy teams, studies and training, by developing and reforming legal and regulatory frameworks, institutions and organisations, and by setting up partnerships, networks, twinnings and pilot projects. Tacis is also a catalyst, unlocking funds from major lenders by providing pre-investment and feasibility studies. Tacis promotes understanding and appreciation of democracy and a market-oriented social and economic system by cultivating links and lasting relationships between organisations in the partner countries and their counterparts in the European Union. The main priorities for Tacis funding are public administration reform, restructuring of state enterprises and private sector development, transport and telecommunications infrastructures, energy, nuclear safety and environment, building an effective food production, processing and distribution systems, developing social services and education. Each country then chooses the priority sectors depending on its needs.

Tacis works with 13 partner countries (12 NIS and Mongolia): Armenia Azerbaijan Belarus

Georgia Kazakhstan Kyrgyzstan

Moldova Mongolia Russian Federation

Tajikistan Turkmenistan Ukraine Uzbekistan

6

Foreword

Since 1991, useful work, in a variety of different forms, has been done to assist partner countries through the Tacis programme. In particular, practical field work, with more visible benefits, has been conducted on a more systematic basis since 1993. A number of projects were successful in developing and testing possible solutions to help partner countries adjust to a market economy. The impact of these projects is not limited to the narrow geographical area in which they were implemented. Results will also benefit organisations and individuals in other regions. The above is the main aim of the Tacis technical dissemination project (TDP). TDP selects projects with result which are worth disseminating, and develops material to facilitate the replication of those useful results. The content of this document is one such action. TDP produces and disseminates various types of material • documentation on comprehensive actions successful in facilitating adjustment to a market economy • tools to help individuals or organisations understand how they perform, and therefore better enable them to adjust • training materials to facilitate quicker adjustment as part of the process of change. Documents edited by TDP are not coloured by a particular ideology or political doctrine, and they do not intend to prescribe any one solution to a problem. What is reflected are merely the results achieved in a given situation, and the details of tools used to good effect by local people in adjusting to their changing environment. Replication of these results is possible, provided readers make an effort to adapt the contents to their local environment. Situations can be similar, but are seldom identical. This brochure was developed on the basis of the experience and results achieved by the project described hereafter.

Some information on the project Title Results

Date Recipients Contractor

Energy handbook for teachers in Moldova The handbook was distributed to each of the secondary schools in Moldova, a circulation of around 3,000 copies. It provides each school with a unique reference book on the topic of energy and includes many suggestions for teachers on how to present the material to their students. 1996 - 1997 State Department of Energy and Ministry of Education in Moldova and schools across the country. F. Javier Verges, Montreal S.A. (Spain)

Some information on this brochure This brochure has been extensively developed from the handbook produced in the Tacis project in Moldova. Here, the reference material has been consolidated and a greater emphasis has been placed upon suggestions for active and modern teaching exercises. The revision and additional material has been provided by two consulting firms, ETSU and Fieldwork, both from UK. Use To provide teachers with key information and practical teaching suggestions to help them build energy into existing school curricula. It covers all aspects of energy from primary resources, conversion to electricity, and energy use and saving in society. It is directed towards teachers of 12-15 year olds in NIS countries, but can be used for any training purpose. Targets Schools and educational establishments - Energy centres in NIS Training institutes. Tacis would be happy to receive suggestions and comments on this document. Please complete the questionnaire at the end of the document and return it to a TDP distributor (see addresses on page 56).

7

Introduction

Energy is an important topic throughout the school curriculum. However, it has traditionally been covered in subjects such as physics, mathematics and chemistry. This sciencebased approach can disguise the social, economic and political issues that are intimately linked to the understanding of energy. This handbook is intended to help you, as a teacher, present a broad and comprehensive understanding of energy to students. The approach proposed in this brochure encourages students to question and debate how energy affects their lives. It helps them to understand the strategic importance of a country’s energy reserves and the political and economic problems that might result from a lack of adequate energy resources. Social and economic development is so closely tied to energy-related issues that any industrial, economic, political or social study requires a clear understanding of the underlying energy situation of a country. Energy issues also transcend national barriers: primary fuels are sold into markets on the other side of the globe, electricity is traded constantly between neighbouring countries, large hydro-electric schemes often draw upon the water resources of several countries and air-borne pollution does not stop at national borders. The handbook is therefore intended to show the importance of energy in a global context.

Purpose of this Handbook This handbook provides reference information and teaching suggestions. It will enable you to develop effective and interesting lessons that will provide students with a firm understanding, not only of what energy is and how it may be used, but of the way it relates to so many key aspects of their lives. It is intended to complement existing science curricula and is aimed at students aged 12-15 years. The handbook has a broad scope including the origins of energy, the sources and extraction of fossil fuels, nuclear power, electricity generation and transmission, and the use of energy in society. It encourages active teaching by getting students to carry out investigative studies into energy topics and to challenge and debate the underlying issues. The energy topic spans many aspects of the school curriculum, and teachers can use this handbook when preparing courses in physics, chemistry, biology, history, geography, economics and social and political studies.

Structure of the handbook The handbook has been written with a structure enabling you to quickly identify the main themes of individual sections, the information presented for reference and the suggestions for teaching activities. Additional topics which are interesting and pertinent to energy have been presented as optional. Each section is presented in the same format: • Main themes • Key information • Optional topics • Suggested activities. The main themes present a quick preview of the areas covered within the section, you can also use them to develop learning objectives for the students. For example, in the section Why energy is important you could present the first theme as an objective - ‘students should understand the significance of energy in mankind’s social and industrial development’. You might like to support this with specific knowledge based items such as - ‘students should be able to explain how charcoal was made and utilised’, or ‘students should be able to describe why coal was so important for early industrial development’.

8

Introduction

The suggested activities include discussions and debates, projects, visits, role playing and making presentations, posters, writing letters and reports, and a number of simple scientific experiments and demonstrations. They encourage the students find out more about their neighbourhood and society and to understand and question how energy is used in their everyday lives, both in the school and in their homes. Some of the exercises have been developed in detail, others provide suggestions that you can expand further for use in class. The more detailed suggestions include a role playing exercise relating to the proposed construction of a nuclear power station in the neighbourhood and undertaking an energy audit project within the school.

9

Why energy is important

Main themes of this chapter    

the significance of energy in mankind’s social and industrial development the finite nature of fossil fuel energy sources, the availalibity of alternatives the political and economic importance of a country’s energy resources the implications energy extraction and use have for the local and global environment.

Key information Social and industrial development The ability to harness different forms of energy as fuel has been central to mankind’s development since prehistoric times. Stone Age man used wood fires to heat caves, for cooking and to harden wooden hunting weapons. Later, in the Bronze and Iron Ages, fire was used to shape metal weapons and implements. Charcoal provided the higher temperatures needed for melting metals. In the 18th and 19th centuries, industrial development was driven by the use of coal to smelt iron for engineering structures - buildings, bridges and the first iron boats. It also fuelled steam engines which could provide mechanical power for industrial processes, such as the textile mills, and provided motive power for ships, trains and even the earliest cars. Even today developments in energy use continue to shape our lives. Space exploration is made possible by the use of solar cells, tiny batteries allow surgeons to use ‘pace-makers’ within the human body to stimulate weak hearts and small nuclear reactors enable submarines to remain submerged for months at a time.

Energy - a finite resource? Today’s society relies on a number of naturally occurring energy reserves called the ‘primary energy resources’. The most important are the fossil fuels (coal, oil and natural gas). Uranium, used as the fuel in nuclear power stations, and renewable energies (including hydropower, solar, wind and geothermal power) are also primary energies. Fossil fuels make up the largest share of our energy resources (Figure 1). But they are finite. Known reserves of natural gas and oil are only predicted to be sufficient for a few decades at present extraction rates, whereas coal and to a greater extent uranium are much more plentiful and will last several thousand years. Exploration for oil and gas continues and new fields are continually being found. However as the most accessible reserves are located and used up, extraction has to operate in more hazardous, remote and technically difficult environments. These problems increase the cost of extraction. Other energy resources like wood, urban waste, agricultural and woodland waste, etc., are widely used but, if we exclude direct use of fuel wood, in total represent less than 3% of world energy consumption. Renewable energy sources like wind power, solar energy and geothermal energy are practically inexhaustible and, in contrast to fossil fuels, create minimal or no pollution. However their high cost and the technical limitations and remoteness of suitable sites, means presently they only make a small contribution to our energy usage.

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Why energy is important

Figure 1: Primary energy use in the world (1994)

Biomass 14% Nuclear 2% Hydro 2%

Oil 37%

Natural gas 21%

Coal 24%

Political and economic importance The social and economic development of any country depends upon the strength and prosperity of its industry and other means of economic production such as agriculture and tourism. It also depends upon good transport and communication infrastructure, and other factors including education and health-care. Adequate and secure energy resources are fundamental to sustaining this development and to maintaining trade and political relations with other countries. Countries possessing their own energy resources, or occupying a geographical position which enables them to purchase reliable energy supplies (e.g. transit countries for gas or oil distribution) have a big advantage when it comes to competing in international markets, because their products can be cheaper. Countries with limited primary energy reserves either have to exploit their own sources at high cost, or to purchase energy from other countries. In either situation the cost can be very high and a vicious circle can develop: the economy is not sufficiently developed to generate funds to pay for necessary fuel and electricity imports, yet without energy, industry lacks a vital resource necessary for expansion which in turn constrains economic growth. Fossil fuel resources are also a very important source from which other products are derived. Oil, gas and coal are the main source of secondary products such as petrochemicals, organic chemicals, plastics and fertilisers. Processing of primary fuels and the industries associated with these secondary products are major sources of employment for countries with indigenous fossil fuel resources.

Why energy is important

11

Optional topic - Energy has many different forms Energy surrounds us in many different forms. The food we eat contains energy (measured in kilo calories or kilojoules) which enables the body to function, to keep warm, to move around. It also enables us to apply energy to other objects, such as lifting a heavy box or pedalling a bicycle. Light and sound are both forms of energy. Consider striking a match: the chemical energy within the match head is released as heat, a visible flame and the sound of the match igniting. Electricity is another form of energy which is so useful because it can be converted easily. Consider the many applications of electricity in daily life e.g. lighting , heating, televisions, telephone, refrigerators etc.

Suggested activities (optional) 

Explain the principle - “Energy can neither be created nor destroyed, merely transformed into different forms”. Discuss simple everyday activities with the students and consider where the energy flows are, e.g. striking a nail with a hammer or driving a car.



Explain the relationships between potential and kinetic energy. Consider a falling object: potential energy is converted into kinetic energy as it drops and gathers speed.



Provide students with a circus of mini-experiments to illustrate how energy is converted from one form into another. These might include the following. Spinning a dynamo to illuminate a light bulb. A piece of curtain rail bent in a loop makes a rolling track for a ball bearing and shows the conversion from potential energy into kinetic. A cut away car battery which students can examine. An inclined plane with model cars. A model steam engine. And many others...

Impact on the environment Fossil fuels can be very polluting - in their extraction, transport and final combustion in the power station, industrial boiler or domestic home (Figure 2). Coal mining is largely carried out in massive open cast mines causing major changes to the landscape and pollution of ground water and underground water courses by washings from the coal ore. Oil is largely transported by boat (oil tanker) and oil spills from damaged or wrecked ships has been responsible for devastation of local ecosystems and coastal wildlife in many areas. Air pollution caused by industrial and transport activities, as well as gas pipelines leak and the natural gas (methane) released contributes to climate change. Perhaps the most visible environmental effect of fossil fuels is in their combustion. Without modern pollutant abatement systems coal power stations release smoke, ash and other pollutants such as sulphur dioxide, nitric oxides and heavy metals. Dispersed from high chimneys these pollutants spread over great distances, frequently crossing country boundaries. They contribute to ozone depletion which reduces the atmosphere’s protecting qualities against the harmful effect of the sun’s rays on the skin of our bodies, and produce “acid rain” with its detrimental effects on lakes and forests and decay of urban buildings. More locally the effects of smaller combustion units, in industry and homes, and the fumes from cars, buses and lorries produce urban pollution or smog which causes severe respiratory and skin irritation problems for people living and working in the cities.

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Why energy is important

Figure 2: Fossil fuel combustion is a major cause of air and water pollution

Energy wastage A large part of the primary energy used today is squandered and wasted. This occurs at all stages of the cycle, from the extraction of primary fuel, conversion to electricity, distribution through the electricity network and finally in its end-use. This wastage comes from the technologies we use but also from the way we use them. Generally society has a poor appreciation of the importance and possibilities of reducing our energy use. If we use energy more efficiently, if we create new products which require less energy, if we change the way we live to reduce energy consumption, we also slow down our consumption of remaining energy resources and reduce the adverse environmental impact of producing and consuming energy. The best way to extend limited energy resources is simple - by consuming less energy. Instilling the idea of the rational use of energy in students is a priority in teaching.

Why energy is important

13

Suggested activities - Why energy is important 

Initiate group discussions about the distribution of the world’s energy resources. These discussions should be based upon up to date information gathered by students from newspapers, television programmes, radio programmes, databases, the Internet, etc. Prepare a sheet of world energy statistics to give out to students to inform the discussions. Encourage groups of students to compile lists of questions about the distribution of the world’s energy resources, then to research answers to the questions with information from a library, databases or the Internet. Groups of students could investigate different issues, countries or regions of the world. The output from the discussions could be poster displays, spoken presentations, video or audio tapes.



Get students to construct energy time lines for their town or for the country. An energy time line is a long sheet of paper set out with the centuries marked along a scale rather like a graph. Some may extend around the classroom and out along the corridor! The dates of key events are marked together with drawings depicting the event. An energy time line might include events such as the opening of a coal mine, the first street lighting, the first cars, the arrival of mains electricity etc. Students would collect information for their time lines by interviewing local officials or older relatives, or by collecting information from local newspaper archives. Try plotting a national energy time line and comparing it one for the town. Other options are to show key events in national or local history or to plot a science and technology time line1.



Make energy maps of the country with the students drawing in the positions of energy resources and infrastructure. Include: fuel reserves (oil, coal, gas-fields), major pipelines and electrical transmission lines, power stations, industrial and urban areas of energy demand, fuel and electricity imports and exports.



Organise a visit to a local coal mine, power station or other energy facility. Alternatively, personnel from these enterprises could be invited to visit the school and talk to the students about their work. It might be worth asking the students if their parents worked in an energy related industry and, if so, whether they would be prepared to talk to the students about their jobs.



Get students to draw up Sankey diagram (Figure 3) showing the energy flows through a process or activity. Consider a power station, house or car. The width of the arrows represents the amount of energy. Energy inputs (fuels, electricity) usually flow into the process from the left and useful energy outputs (heating lighting mechanical power, chemical energy) and losses (heat, noise etc.) flow out to the right.

Figure 3: Sankey diagram for a coal power station

Waste Heat

70% (1) Timeline references: The timetables of History by Bernard Grun published by Touchstone, and The timetables of Science by Hellemans and Bunch published by Simon and Schuster.

Primary Fuel

100%

30%

Electricity

14

Sources of energy

Main themes of this chapter  how fossil fuels (oil, coal and gas) were formed and how they are extracted by man for use as fuels  the political and strategic importance of energy reserves in terms of location, transportation and wealth  the principles of nuclear power and the issues of safety and disposal  the advantages offered by renewable technologies and their main limitations.

This chapter is structured in three parts, each with themes, key information and suggested activities. Fossil fuels - including:

• oil • natural gas • coal.

Nuclear power Renewable energies - including: • solar • wind • biomass • water • geothermal. Figure 4: The earth provides us with many natural sources of energy

15

Fossil fuels

Main themes of this chapter  how fossil fuels (oil, coal and gas) were formed and how they are extracted by man for use as fuels  the finite nature of fossil fuel reserves and the increasing difficulty and expense of their extraction  the hazardous working conditions that can be associated with fossil fuel extraction (especially for coal mining)  the advantages of natural gas as a clean and convenient fuel that replaced many traditional uses of coal and oil  the political and strategic importance of energy reserves in terms of location, transportation and wealth.

Key information The fossil fuels were formed from the remains of plants and animals from many millions of years ago. Through the actions of micro-organisms and particular conditions of immense temperature and pressure, these remains have been transformed into carbon deposits trapped within the ground or deep beneath the oceans. The time-scale of this process is so huge, compared to that of mankind’s development, that the reserves are considered to be finite and our continued extraction will ultimately deplete known reserves completely. There is a very strong incentive to look for ‘sustainable’ energy solutions and to maximise the effectiveness with which we utilise energy in order to prolong the lifetime of the fossil fuel reserves for future generations. Predictions of oil and gas resources indicate they will last for around another 40 years. New deposits are continually being located, but energy demand is also increasing and predictions of how long known reserves will last have remained approximately static since the 1960s. Known coal reserves are much larger and are predicted to last up to two thousand years. Fossil fuels are not only important for their energetic value but also as the raw material for many products of everyday life. For example, consider a car: fossil fuels not only power the car (in the form of petrol) and provide the energy for its manufacture, but provide the basic material for the tyres, the dashboard, the wiring insulation and the paintwork. The tar and bitumen used to construct the road is also derived from fossil fuels.

Oil What is oil? When oil is extracted from the ground it is called “crude oil”. It floats on water, has a heavy, characteristic smell and has a colour which, depending on its composition, goes from yellow to deepest black, but always has the characteristic ‘oil film’ iridescence. It is a non-uniform, highly complex mixture of hydrocarbons (carbon and hydrogen chains) with paraffins, naphthenes and aromatic compounds. It also has small quantities of other components including heavy metals and sulphur.

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Fossil fuels

How oil was formed Oil is found in conjunction with sedimentary rocks of marine origin. It was formed by the gradual build-up of deposits of plankton and sea creatures on the ocean bed millions of years ago. As the climates changed the seas dried up and these deposits came to be covered in successive layers and strata of sediment. Over the course of time this sediment turned to thousands of metres of sedimentary rock and the continued action of compaction and high temperature brought about the transformation to bitumen and then oil. These deposits became trapped between impermeable layers of rock, and tectonic movement and geological faulting leads to the formation of underground reservoirs of oil, called oil-fields. Figure 5: Oil deposit trapped between rock strata

Drilling station

Oil

Layers and sedimentary rock

Exploration and extraction Detecting oil-fields is a complicated and expensive process. There is a very high degree of uncertainty and only 1 in 10 of the explorations are typically successful. The expense of oil exploration can only be afforded by a handful of major international companies who now dominate the oil industry. Modern detection is highly scientific involving geophysical methods including seismic, magnetic, electrical resistance and gravitational techniques. These techniques provide evidence for the location of an oil-field however pilot drilling wells are required to confirm the precise location, oil quality and importance of discovered oil fields. Nowadays oil extraction is carried out both on land and out at sea. These off-shore locations use drilling platforms or oil-rigs and the process is more complicated and hazardous. Over half of the crude oil extracted in the world is from off-shore locations. As the most easily accessed fields are found and exploited, oil companies must search further, and deeper, for new oil-fields. Already drillings of 4000 metres and even up to 8000 metres in depth are normal both on land and off-shore. Once the exploratory and preparatory phase is completed (typically three years or more) and the project assessed as economically viable, the bore is prepared for the extraction of oil. A metal bore-hole casing protects the oil from contamination with sand residues and the oil is forced up the bore by the pressure of gases trapped in the pocket of the deposit.

Fossil fuels

17

The crude oil is transported to storage depots and refineries in large pipelines or, for transportation by sea, in oil tankers of up to 500,000 tonnes capacity. Many safety features are necessary to prevent damage to the pipelines and the oil tankers. Leaks lead to a loss of oil, and major spills can have dire consequences for the environment. At sea crude oil forms slicks on the surface of the water which kills fish and seabirds and endangers coastal habitats. Oil tankers are designed with compartmentalised holds to balance the ship’s loading and to reduce the quantity of oil lost should there be a collision or other problem. Optional topic - Oil has many non-energy uses The most important use of refined oil, besides that for energy, is as transport fuel for cars, lorries, trains and aeroplanes. It has many other extremely valuable components whose derivatives are separated out from crude oil in the distillation process. This technique works using a distillation column with graduated temperatures at which the various components, or fractions, of oil are separated out, condensed and collected. Initial refining releases asphalts, lubricants, combustible fuels and raw materials for the petro-chemical industry. Further processing yields innumerable end products such as: fertilisers, pesticides, resins, pharmaceutical products, plastics, polythene, polypropylene, polyesters, textile fibres, explosives, detergents, adhesives, dyes, paint and others. Suggested activities (optional) 

Ask students to identify items in the classroom (or home) that have been derived from oil products. Think of alternative materials that might have been used. Discuss the importance of petrochemicals to modern society.



Create life-cycle charts, get students to produce flow charts of the production processes involved in the conversion of oil into everyday objects. Indicate the amount of energy used at each stage. Groups of students could be given different objects to investigate, each made from different materials, i.e. PVC, polythene, polypropylene, etc. Stage an exhibition of their charts as posters at the end of the task and discuss the similarities and differences between the processes. Ask each group to contribute questions about their exhibit to a class quiz.



Show a laboratory distillation experiment. Illustrate the fractional distillation process which takes place in an oil refinery using a laboratory distillation column. Students can examine the fractions obtained and see how they differ from the original fluid from which they came.

Where oil is found Many countries in the world have significant oil reserves and more than 50 produce over a million tonnes of crude oil each year, however the greatest part of world oil production is controlled by a relatively small number of countries. Proved world oil reserves are calculated at 14 billion tonnes, with the actual resource being considerably larger. Proved reserves are the quantities of oil that are known to be in place and are considered to be economically recoverable with present technologies. The world distribution of proved oil reserves is shown in the chart (Figure 6).

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Fossil fuels

Figure 6: Distribution of proved world oil reserves

USA 3% Abu Dhabi 10%

Mexico 6% Venezuela 8%

Iran 10%

UK 0.4% Russian Federation 5% India 0.6% China 3%

Kuwait 11%

Libya 2% Nigeria 2%

Iraq 11%

Saudi Arabia 29%

Although world trade in oil is governed by international agreements between countries and multinational companies, possession of oil reserves remains a very important strategic strength. Control of the distribution channels for oil is also strategically very important. Examples include the pipelines from Russian oil-fields to Western European countries and the shipping trade routes of the Suez Canal in Africa and the Panama Canal in Central America. Figure 7: World trade routes for distribution of oil and petroleum

Fossil fuels

19

Natural gas A clean convenient fuel Natural gas is colourless, odourless gas comprising largely methane and small quantities of other hydrocarbons such ethane and propane. It is an extremely convenient and versatile fuel which is easily extracted. It burns with very little pollution and is distributed through a pipeline network to the final point of use. It can be used directly within the home, or industry, and there is little requirement for storage. The use of natural gas as a primary fuel is relatively recent, as for many years gas was seen as a necessary by-product from the extraction of crude oil. From 1960, as pipelines and local gas transmission networks have been constructed, the growth in demand for natural gas has been spectacular. Now gas supplies over 30% of the world’s total energy demand . Like oil, natural gas is an important raw material for the petro-chemical industry and is used to obtain a multitude of products including ammonia, (for nitrogen fertilisers) and methanol (the basis of many plastics and other synthetic materials).

Origins and extraction Natural gas is often found together with crude oil deposits and is formed by similar processes. It is also produced by the degradation of older carbon deposits, such as coal. As crude oil reserves are extracted, natural gas accumulates in the upper chambers of the seam and can be recovered once the extraction of crude is no longer viable. In this type of gas field, quantities of propane and butane are also recovered which are utilised for domestic and industrial use as LPG (liquid propane gas). Natural gas is also found in dry seams, not in association with oil, as in the extensive Russian and NIS region gas fields. Detection and extraction techniques are similar to those for oil. Wells are typically 5000 metres deep, or more, and are lined to reduce contamination. The extracted gas is cleaned by absorption or cryogenic processes to remove heavy hydrocarbons and other impurities like sulphur.

Transport and pipelines Natural gas often has to be transported great distances from the gas fields to the demand centres. Two methods are used: • by ship, carried as liquid methane at around 160°C below zero • pumped through large diameter pipelines. Pipeline technology has played a key role in the development of markets for natural gas. Gas has to be transported vast distances, often across continents, and users require stability in pressure and continuous supply. Large diameter pipes (up to around 4m) are used to minimise pressure, yet the cost of the pipe increases quickly with pipe size and intermediate pumping stations are required. Nowadays, gas pipelines even cross straits joining continents, like that of Gibraltar which ensures the supply of gas from Algeria to Europe. Major pipelines bring gas from Russia and Scandinavia into Western and Central Europe and others supply the USA and Central America from the Canadian fields. A major pipeline project is currently underway in Latin America to bring gas from the Andes in the West of the continent, across the Amazon Basin to supply the industrial regions of Brazil in the East. The large liquid gas distribution centres are in the Mediterranean (Algeria and Libya), the Pacific Rim (Indonesia, Brunei, Malaysia and Alaska) and NIS countries. The Russian and other NIS gas fields produce around half of the world’s present gas demand. Other major fields are in the Middle East and North Sea.

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Fossil fuels

Coal The fuel of industrial development Coal provided the energy to fuel the industrial revolution in Britain in the eighteenth and nineteenth centuries. It was relatively simple to mine and required little preparation. Coal provided the energy required to fire blast furnaces to produce iron, to fuel reciprocating steam engines for mechanical power and for the railways to transport raw materials and products. The importance of coal diminished with the discovery of oil, and many applications switched towards this more convenient and economical fuel. However, the oil crises of the 1970s and the relative abundance of coal has restored the balance and coal will remain a very significant fuel well into the future. The main uses of coal today are: • as fuel in thermo-electric power stations • within the iron and steel industry, both as raw material for coke and as a fuel for smelting and heating processes. Before the exploitation of natural gas, coal was widely used to generate ‘town gas’ for urban use. Like oil and gas it also provides raw materials for the petrochemical industry.

Composition of coal Coal is a solid, black carbon material with varying amounts different minerals which form inert residues (ash) when the coal is burnt. It also contains volatile hydrocarbons and other impurities e.g. sulphur.

How coal is formed Like oil and gas which were formed from marine deposits, coal has also been formed from the action of great pressure and temperature on carbonaceous material but its origins lie in the plant material found in the swamps and forests that used to cover much of the earth’s surface 300 million years ago. As seas advanced and receded over the land, successive layers of plant material and sediment were built up. The weight of this material, and tectonic movement provided the necessary temperature and pressure conditions which have ultimately produced the limestone strata and coal seams exploited in our coal mines today. It is interesting to consider that the origin of coal is the chemical energy that was stored in plant material by photosynthesis of the sun’s rays hundreds of millions of years ago.

Optional topic - Mining coal The coal mining technique depends upon the shape and depth of the coal seam that is being stripped. There are two approaches: • open-cast mining - where coal seams are horizontal and relatively near the surface. This is inexpensive, yet coal seams tend to be of lower purity and quality • deep shaft mining - where vertical and horizontal shafts are used to access the coal face deep underground. Deep shaft mining gives access to better quality coal seams but is more expensive than open cast mining and in the past has been a very hazardous industry. The coal is extracted using mechanical cutting machines or with controlled explosives. In deep mining the seams used to be worked by hand in narrow galleries. Now where the seam is of sufficient thickness and regularity the coal face can be worked by sophisticated machines which cut the coal and transport it back to the vertical shafts in automated wagons. The roofs of the working galleries and transport shafts are ‘shored up’ with metal frames and timbers to prevent collapse, and ventilation and adequate protection against flooding are vital safety features.

Fossil fuels

21

At the surface the extracted coal has to be separated from inert rock material. This is achieved through a series of mechanical size classification processes and floatation techniques. Coal is transported by rail and ship.

Suggested activities (optional) 

Get students to draw diagrams of the structure and workings of a deep shaft coal mine. Show the coal face galleries, the vertical lift shafts, the ventilation shafts and other features which demonstrate its workings.



Students could write short descriptions or stories of a day-in-the-life of a miner. Compare the lifestyle of a miner in the early part of the 20th century with a miner working in a modern coal mine.

Mining - a dangerous industry Coal mining is a hazardous industry which has been made vastly safer through the application of modern and sophisticated machinery. However, it still requires working deep underground in tightly controlled spaces with the inherent risks of roof collapse, explosion, flooding and the harmful effects of a dust laden atmosphere. Explosion presents a very significant risk. Methane gas becomes trapped in pockets within the coal and in suitable mixture with air (around 5%), can be ignited by a spark with catastrophic consequences. Other less immediate dangers are the continued exposure to coal dust which can cause bronchial diseases in mine workers, the most well known being ‘silicosis’. Figure 8: Typical deep-shaft mine, showing the coal face and working galleries and shafts

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Fossil fuels

Pollution from coal combustion Coal contains ash and impurities (sulphur, heavy metals and others) that are released on combustion and are damaging to the environment. Various technologies may be employed in power stations to limit their release, however the extent to which they are applied depends upon environmental legislation on a country by country basis. Coal power stations use washed coal which contains less dust and organic matter. The coal is generally pulverised and blown into the combustion chamber to ignite and combust efficiently in a specially designed burner. Ash and clinker is collected from the base of boiler and particulate dust is removed from the exhaust gases using an electrostatic precipitation filter. This is simply a large chamber filled with vertically hanging wires which have a small electrical charge to which the dust particles are attracted. More sophisticated and modern power stations will also have flue-gas desulphurisation units which will scrub out emissions of SO2 from the exhaust. This process has become increasingly important due to the effects of acid rain resulting from power station emissions and the increasing cost of high quality (low sulphur) coal. Cleaner coal technologies currently being developed will gasify the coal rather than use direct combustion. The gas can be fired directly into a gas turbine which will raise efficiency. Another benefit of gasification is that the gas can be cleaned of impurities prior to combustion.

Coal reserves Coal reserves are found all over the world. Europe has a long tradition of coal mining, but due to a reliance on expensive deep shaft mining the industry has contracted rapidly in the past twenty years. Eastern Europe, Russia and Ukraine are still major coal producers and exporters. The newest coal producers are countries such as Colombia, Australia, Canada and South Africa which operate massive open-cast mines and export a high proportion of their output. China, India and Korea have extensive coal resources but export little as it is needed to provide for their internal consumption. Present estimates of world coal resources are around 10 million million tonnes which would satisfy the world’s present energy demand for 2000 years. Although coal seems to present a long term solution to man’s energy needs, coal combustion has major impacts on local and global environments. Research into cleaner coal technologies may provide solutions which can satisfactorily reduce the environmental effects associated with present coal usage.

Suggested activities - Fossil fuels 

International trade in fossil fuels. Organise a project amongst groups of students into the issues relating to the transport of fossil fuels such great distances around the world. One group might look at the distribution of energy resources and energy demand across the world. Another group the energy costs of transporting fuels by barge, rail road or pipeline. Another might consider the environmental risks associated with different forms of transporting fossil fuels. Present the results as a poster exhibition or choose a specific route and debate in groups the best options for transport of fuels. Groups might be economists, oil companies and environmentalists.



Investigate multinational oil companies. Oil exploration and production world-wide is dominated by multinational companies which have enormous economic influence. Students could research into the major oil companies (e.g. Exxon, Shell, Mobil and others) and the regions in which they operate. Use newspapers, libraries, Internet etc. for information sources.

Fossil fuels



23

Investigate the effects of oil on water and feathers. Students can examine the fine structure of feathers using a hand lens or magnifying glass. Wet the feathers with water and re-examine. Repeat with engine oil. Find out whether oiled feathers float as well as clean ones. Investigate the floating property of oil and the effects of dispersants such as detergent. This should lead to better understanding of the properties of oil and the effects of spillage on sea birds (loss of insulation, water resistance and ingestion of oil through preening). Combustion of coal and oil releases sulphur dioxides and nitrogen oxides into the atmosphere. The pollution and acidification resulting from these atmospheric pollutants can have serious effects on plant growth and decay of stone buildings. The following suggestions each consider the effects of atmospheric pollution.



Effect of air pollution on seedlings. Sodium metabisulphite tablets (known as Camden tablets) dissolved in water, release small quantities of sulphur dioxide of comparable concentrations to that found in polluted air. Students should first sow some seeds such as mustard or cress in Petri dishes and grow them on until they are small seedlings - between forty and one hundred seedlings in each Petri dish. The Petri dishes and seedlings are then placed inside a plastic bag, together with another Petri dish containing a sodium metabisulphite tablet dissolved in a little water. The bag is sealed, labelled and left in a sunny place. Also set up a control without the metabisulphite tablet for comparison. Observe the seedlings over the next ten days and record their growth. Get the students to examine the effects of different concentrations, light intensity and temperature on seedling growth.



Corrosion effect of pollution on buildings. Examine the effect of sulphur dioxide on various building materials by placing samples of limestone, tile, brick etc. in a bell jar and introduce sulphur dioxide gas from a sodium metabisulphite solution or directly from a cylinder. This should be carried out in a fume cupboard. Observe the changes to the stone over the following three weeks. The bell jar should not be removed from this experiment during this period. The permeable stones will show clear evidence of pitting and corrosion. Get students to look for similar signs of pollution corrosion of stonework (old buildings, statues etc.) in their town or city.



Lichen surveys. Environmental scientists sometimes use lichen surveys to find out the pollution level in a local area. Lichens are growths on trees and other surfaces. They are generally pale in colour and should not be confused with mosses which are greener and more plant like. Lichen species No lichens Powdery lichens Crusty lichens Leafy lichens Shrubby lichens Wispy lichens like Usnea

Pollution level Extremely polluted Very polluted Quite polluted Slightly polluted Very slightly polluted Clean air

Pollution scale 5 4 3 2 1 0

Different kinds of lichen species can tolerate different levels of air pollution, in particular different concentrations of sulphur dioxide. It follows that we can use them as pollution indicators. The chart sets out the different kinds of lichens and the pollution levels which they indicate.

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Fossil fuels

Check the local lichen species near to the school and give students drawings and descriptions of them to make them easier to identify. Groups of students can search for lichens and mark the corresponding pollution levels at various sites on a provided map. This can be developed into an air pollution map of the area onto which students can mark possible sources of air pollution such as power stations, factories, major roads. The students would then have sufficient data to drawn some conclusions about the pattern of air pollution in the area.

25

Nuclear power

Main themes of this chapter  the concepts of nuclear fission and nuclear fusion  the principle of how a nuclear power station works  radiation risks, safety and the issue of waste disposal.

Key information Free energy? In the second half of this century we have become increasingly aware of the finite nature of the fossil fuel resources upon which our industrial societies depend. Renewable energy from the sun and the wind provides a truly sustainable source but one that can only support a tiny fraction of our present energy demand. In the 1950s controlled nuclear fission was achieved and the possibility of using small quantities of uranium to produce massive amounts of energy was realised. This discovery led to the popular claims that the advent of nuclear power stations would provide electricity that was ‘too cheap to meter’ and it was hailed as a possible solution to our dependence upon fossil fuels. The reality has been very different. Nuclear programmes were taken up by most industrialised countries and nuclear stations have been operating for over 30 years. In that time the risks of nuclear power has been made very apparent by a few major incidents, and the full costs of decommissioning old stations and safely disposing of nuclear waste are only now being appreciated. Even after this time a satisfactory solution for the storage of, even medium and low level, radioactive waste has not been agreed. The full social and economic costs of nuclear power are still not fully known.

Fission and fusion There are two possibilities for extracting useful energy from nuclear reactions. Fission - the splitting of large molecular weight nuclei (uranium) and the associated release of heat energy. This is a slow natural process (in uranium ores for example) which is accelerated in a controlled fashion in a nuclear reactor. It forms the basis of all existing nuclear power stations and was derived from the development of the ‘uranium bomb’ at the end of the second world war which produces an uncontrolled chain nuclear reaction and devastating energy release. Fusion - the combining of low molecular weight nuclei to produce a heavier element (e.g. hydrogen to helium) with release of heat energy. This is the reaction that sustains the heat of the sun and takes place at a temperature of around 15 million degrees centigrade! Scientists have been trying to simulate and harness this fusion reaction in very large ring-shaped electromagnetic fields (called a torus). These machines can accelerate atoms to vast speeds in a vacuum in an attempt to create the right conditions for fusion to occur. Nuclear fusion offers the promise of nuclear power without the radiation dangers and waste disposal problems of conventional nuclear fission reactors. However, despite extensive international research, nuclear fusion has still not been proven to be economically feasible. Commercial power generation from nuclear fusion will not be available for many years, if it proves to be possible at all.

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Nuclear power

Harnessing nuclear energy Nuclear power stations use the uranium fission reaction to release heat which is recovered in a heat exchanger and used to raise steam to drive turbines and electrical generators. This steam cycle and generation elements are exactly the same as in a conventional fossil fuel generating station. The nuclear reactions take place in the heavily shielded and fully automated reactor core. Uranium releases neutrons which collide and set off further chain reactions. The speed of the reaction is controlled by the insertion of moderators (usually graphite rods) which absorb free neutrons. The heat generated by the reaction is extracted through a heat exchange circuit which in turn raises the temperature of water to high pressure steam and is used to drive the turbines.

Figure 9: Schematic of a nuclear power station

Moderator rods

Turbine

Generator

Condensor Uranium fuel rods Water circuit

Pump

Heat exchanger

The majority of existing nuclear stations use an enriched uranium fuel and water as the cooling agent. • Pressurised water reactors (PWR or BBEP) use water as the reaction moderator. • Light water graphite reactors (LWGR or PBMK) use graphite for the moderator. • CANDU, developed in Canada, uses a natural uranium fuel and heavy water as the moderator and cooling agent. This type of reactor accounts for only around 10% of the world’s nuclear generating capacity.

Optional topic - Nuclear power in the world Presently there are around 430 nuclear reactors in operation around the world which together provide 17% of total world electricity generation. This represents less than 5% of our total energy needs. Whilst overall dependence on nuclear power is less than a fifth of electricity generation capacity, some countries have invested heavily in nuclear power. For example 76% of France’s generating capacity is nuclear and in Lithuania it is even higher at 85%. The following countries have more than 40% installed nuclear capacity: Belgium, Sweden, Bulgaria, Slovak Republic, Hungary, Switzerland. In the NIS region, Ukraine has around 38% and Russia 12%. These countries have a high national dependence upon nuclear power generation and substitution to another non-nuclear source would be complex and expensive.

Nuclear power

27

Suggested activities (optional) 

Ask the class make a list of the advantages and disadvantages of a decision to decommission nuclear power stations on safety considerations in country which has a high proportion of nuclear power (such as France) or in countries where the used technology is becoming outdated. The output from the exercise might be presented as a television style documentary with role play interviews and debates. If you have access to a video camera - record it. Alternatively ask students to write letters as if to the government or national newspapers. Get groups of students to take the viewpoints of different interest groups such as environmental groups, economists, workers from the nuclear power stations and others.

Radiation and nuclear safety Nuclear power stations do not release dangerous radiation when in normal operation, and there have been very few nuclear incidents that have actually caused harm to human health. Nonetheless, radiation can be extremely dangerous and very careful precautions have to be taken for workers within nuclear power stations, for handling radioactive waste and in carrying out repairs and decommissioning. Radiation cannot be seen or felt and radiation receptive film badges and Geiger counters are used by nuclear workers to ensure they do not exceed the advised safe radiation dosage throughout their lifetime. Two major accidents have occurred in nuclear stations: • Three Mile Island power station in Pennsylvania, USA (28 March 1979) • Chernobyl, Ukraine (26 April 1986) in which dozens of people were killed and it is estimated that the health of over 10,000 people will be affected by the radiation fallout. These accidents, and above all that of Chernobyl, have been responsible for informing world opinion of the very real danger that nuclear energy can pose. The Chernobyl accident raised awareness of the importance of international dialogue to control nuclear energy and the crucial need to set in place adequate security measures.

A long term disposal problem Perhaps the most significant question that remains unanswered is the safe disposal of radioactive waste. High level radioactive waste, such as spent fuel rods or components from a decommissioned reactor core, may not decay to a safe level of radioactivity for several thousand years and is likely to remain very hot (up to 400 °C) for a significant time. Low level waste, which includes tools, clothing etc. may require protected storage for a few hundred years before being considered safe. Spend fuel rods can be reprocessed, which helps to reduce the quantity of high level waste generated. The design of suitable storage facilities presents a massive challenge to nuclear technologists. The options include, vitrification (sealing within glass) and encasement in concrete, deep underground storage chambers and ocean burial. The research and debate is on-going and nuclear waste is presently held in long term, but temporary, storage facilities.

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Nuclear power

Suggested activities - Nuclear power 

Role play on sitting a nuclear power station in the neighbourhood. Ask the students to imagine that a nuclear power station is to be built near to the school. However, before the final decision is to be made there will be a public meeting at which three groups of people will have an opportunity to present their views. These are, a group of engineers and scientists who have designed the power station, a group of local people and a group of local politicians. Divide the class into these three groups and give them the rest of the lesson to prepare their case. The role play would take place in a subsequent lesson in the form of a public meeting. Students should be given information sheets explaining something about the proposed site and the economic case for the power station. Various other resources might also be made available to the students such as databases, textbooks, a library, local newspapers, magazine articles or video material. The members of each group should also be given the appropriate role play card for their group set out below. Group A: Engineers and scientists You want the power station to be built because you think that nuclear power is a clean and efficient way to build up the prosperity in the region. Also if this station is built it will keep you in work and make it more likely that other stations are built in the future. You are convinced that any safety problems have been overcome. You expect the local politicians to support you because they persuaded you to bring the power station to this site. However, you also know that they will want to test you out on issues of interest to their electorate in public. Members of the other groups are likely to ask you about: • Safety issues • Pollution issues • Disposal of waste • Employment matters • Cost of energy produced in comparison with alternative energy sources. You need to research these matters thoroughly. Group B: Local people You want to know whether the new power station will bring any benefits to your town. How many jobs will the power station create? Will it employ local people or will the jobs go to highly skilled people from other parts of the country? Will it bring wealth to the area which might benefit local business? Perhaps it will be less expensive. Perhaps it will mean improvement to local services such as roads and communications. On the other hand it may bring pollution, risk of accidents and danger of cancers. You want to be convinced that that the advantages outweigh the disadvantages. The main issues are: • Safety issues • Pollution issues • Disposal of waste • Employment matters • Cost of energy produced. You need to research these matters thoroughly.

Nuclear power

29

Group C: Local politicians As local politicians you see part of a national and regional picture. You know that the area needs more energy in order to develop and that nuclear power is cheap and efficient. The power station has got to go somewhere, so why not here. You have worked hard to get this project because it should bring jobs and prosperity to the area. However, the people elected you so you’ve got to listen to their concerns. You will have to live with this decision long after the scientists and engineers have left to build there next power station. So on the one hand you seek reassurance from the scientists and engineers, on the other hand you seek to reassure the local people. The main issues are: • Safety issues • Pollution issues • Disposal of waste • Employment matters • Cost of energy. You need to research these matters thoroughly. Towards the end of the preparation phase, teachers should check that the groups are ready to proceed with the role play during the following session. Teachers should give some thought to the layout of furniture for the role play lesson. A seating plan “in the round” is ideal for this kind of activity. The teacher should plan the role play lesson carefully with a short introduction at the beginning of the session and a period at the end for students to come out of role and to discuss the events of the role play in a detached fashion. 

Similarities and differences between nuclear power stations and fossil fuel stations. Ask the students to draw comparisons and contrasts between nuclear and conventional fossil fuel generating stations. Present the findings as posters.



Living with nuclear power. Lead a discussion with students about how they would feel if they had to live near a nuclear power station. The students could then write this up as a letter to a friend discussing their feelings.

30

Renewable energy

Main themes of this chapter  what are ‘renewable energy technologies’  the sun as the ultimate source of all renewable energies  renewable sources offer inexhaustible and non-polluting energy supplies, yet there are other environmental disadvantages  the limiting factors on renewable - largely high cost, and location of suitable sites  the role of renewable energies in a balanced energy system.

Key information What are renewable energies? Our present energy systems rely to a great extent upon fossil fuels (and to a smaller extent uranium) of which there is only a finite quantity. Ultimately these resources will run out. Renewable energy sources, sometimes known as ‘alternative energy sources’, are not of a finite nature. They are continually replenished by the earth’s natural cycles and therefore provide an inexhaustible source of energy. They may be grouped into five broad categories: • solar • wind • biomass • water • geothermal. The water category includes power from rivers, dams and oceans. Renewable energies seem to provide an ideal energy source: they are inexhaustible and environmentally friendly. They do not release carbon dioxide or other pollutants and they create very little waste. However, large-scale utilisation has its difficulties due to the diffuse nature of the resource, the tendency for the best resource sites to be distant from centres of energy demand and the high cost of the technologies required. Presently renewable contribute only around 2.5% to man’s energy demand world-wide. Some countries utilise a high proportion of renewable sources. In Brazil over 95% of electricity generation is from hydro-electric stations, and the use of wood and other biomass is still extremely important in rural Africa for cooking and heating.

All renewable energies have solar origins The source of each of the renewable energies is the sun. Solar energy is the capture of direct radiation from the sun’s rays. Biomass is composed of plant material which has derived its energy from the sun through photosynthesis. The rivers are fed by rain which is created by the convection cycle of water vapour from oceans and lakes, again driven by the heat of the sun. Wind flows across the earth’s surface in response to differential heating of its surface by the sun. Indeed the fossil fuels also have their origins in the sun’s energy, but on a massive time cycle. As we have seen coal is the final product of decomposed plant matter which, like biomass, derived its energy from the sun.

Renewable energy

31

Not always environmentally friendly Renewable are considered to be highly environmentally friendly. They do not produce the carbon dioxide and other pollutants resulting from fossil fuel combustion, and they do not leave a legacy of radioactive waste as from nuclear power. However they are not without their problems and larger projects have come under intense criticism in some countries. For instance huge hydro-electric stations have involved damming vast areas of land, displacing rural populations affecting local climatic conditions and wildlife and disrupting use of the river for irrigation both up and downstream from the dam. Other examples are the construction of major ‘wind farms’, areas of often scenically important land, with large groupings of wind turbines. The largest wind farms in Europe contain around 100 turbines, in parts of the USA there are much more extensive sites. Another aspect to consider is the environmental cost of producing the technologies used to capture renewable energies e.g. the energy and raw materials utilised to produce a wind turbine.

Commercial opportunities for renewable energies Renewable energy sources have a valuable role to fulfil in a balanced energy system. They are a dispersed and expensive energy resource that will probably never fully replace our usage of fossil fuels. However in conjunction with activities to reduce our consumption of energy, renewable can help to diminish our dependence on fossil fuel and thereby slow the rate of carbon dioxide release and other pollution. There are many opportunities where renewable can compete economically with the conventional alternatives, and the cost of the technologies is constantly being driven down as on-going research and development activities improve efficiency and commercial production volumes increase.

Solar energy Students should understand: • the concepts of passive solar heating and photovoltaics (pv) • commercial applications for solar energy.

Energy from the sun The earth receives almost all of its energy from the sun. On reaching the earth’s atmosphere, radiation from the sun is part reflected, absorbed, refracted and radiated. The atmosphere both shields us from the full strength of the sun’s radiation and provides an insulating blanket which retains essential warmth. One estimate suggests that the sun provides the earth with 15,000 times the total energy consumed by man each year. It is an enormous source of energy and there are several ways in which it may be harnessed.

Solar heating Solar power can be used to provide heating for buildings through appropriate design and orientation. This is called passive solar design, and uses windows and conservatories to trap the heat of the sun during the day. Good insulation and thermal storage ensures this heat is retained. Passive solar buildings have plenty of natural light and so also reduce electrical lighting demands. Another form of solar heating uses an active system (Figure 10). Here a solar panel is used to collect heat from the sun and using water, or sometimes oil, in a heat exchange circuit heat can be stored and distributed around the house. Swimming pools make

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Renewable energy

excellent heat stores for larger systems, perhaps in hotels or sports complexes. Active solar is most commonly used to assist domestic hot water and heating systems. Figure 10: Active solar heating system

Collector Header tank Pump

Hot water tank

Cold input

Hot water

Heat exchange tank

Active solar systems are also used for power generation, such as a very large example in California which produces 10 MW of electricity. A huge array of mirrors concentrates the sun’s rays and is used to heat water and raise steam to drive a turbine and generate electricity. The mirror automatically track and respond to the sun’s movement throughout the day. Smaller systems (up to 15 kW) will use a single reflective dish perhaps up to 15 m in diameter.

Photovoltaic systems Solar cells make use of the particular characteristic of silicon to emit a small quantity of electricity when struck by sunlight. This is called the photovoltaic effect. Other materials are also photosensitive, but silicon is the material generally used. It is in plentiful supply and makes up around 28% of the earth’s crust. Individual cells generate only around 1 watt of electricity, however when multiple cells are connected together in panels to form an array they can produce tens of kilowatts. This is tiny compared to conventional generation (a fossil fuel power station will produce hundreds of megawatts) but there are applications especially in remote and arid areas where solar power can be the best solution, or perhaps the only possible solution!. Silicon technology has advanced greatly in recent years, improving the efficiency of solar panels and reducing their cost. Photovoltaics are used extensively for remote installations - the best example being their use in outer space for powering satellite communication systems. They are also used increasingly for isolated terrestrial applications such as field medical centres (refrigerators for storing vaccines and charging batteries) and running pumps for drinking water and irrigation.

Optional topic - Designing solar collectors Matt black surfaces absorb more radiation than white, shiny surfaces and protecting absorbers from wind chill under glass increases the heating effect by trapping reflected radiation and allowing convection.

Renewable energy

33

Suggested activities (optional) 

Heating effects. Examine the different heating effects on containers of water painted in white and black and exposed to the sun. How does the temperature vary if similar containers are enclosed in a glass topped box?

Wind Students should understand: • the wind has been harnessed for centuries for mechanical energy, only recently for electricity generation • wind-speed and sitting requirements for wind turbines • the importance of technological developments in turbine design • visual and noise impact can affect planning.

Wind power - not a new technology The power of the wind has been harnessed by man for thousands of years. The early sailing ships relied solely on the wind for motive power, windmills have been used for centuries for pumping water and grinding corn. Nowadays the wind is harnessed to generate electricity in modern wind turbines (Figure 11), either as single units perhaps supplying electricity to a farm, or as arrays of turbines which feed power into the electricity grid. The smallest turbines may only generate 500 watts, sufficient to power a television, and the largest are several megawatts, enough power for a small town. Multiple arrays, called wind-farms typically use turbines of around 300 kW which may stand 50m high and have a blade diameter of 30m. Figure 11: Big turbines can be erected on the ground

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Renewable energy

Choosing the right sites Wind turbines can only be installed where the wind resource is adequate. The ideal conditions are for a steady wind, throughout the year and with a regular wind speed of 6 to 25 metres per second. Such sites are usually found in hilly and often coastal areas. Careful monitoring and wind mapping is required to assess the suitability of proposed sites. Sites should also be close enough to existing electricity distribution systems and centres of demand. Wind turbines have a major visual impact, and their location on high exposed areas, has given rise to grave public concern about spoiling the countryside’s traditional views. Noise is also an issue. In Europe many of the technically best sites are also areas well known and used by the public for leisure activities, and obtaining planning permission for the larger wind-farms has become increasingly difficult. As the technology advances, and the need for regular servicing diminishes, the sitting of turbines a short distance out to sea has come more viable. This increases the cost, and the technical challenges are harder, yet the wind resources are better and the issues of visual and noise intrusion resolved. There is an example of an off-shore wind farm off the coast of Denmark.

Turbine construction Modern turbines are large structures that need to withstand severe storm and wind conditions, yet remain light and responsive to operation in conditions of little wind. The rotor is designed to operate at a fixed speed (typically 34 rpm) and the angle of the blades is automatically trimmed to achieve this speed. The head or ‘nacelle’ of the turbine is also turned by a yaw motor so that it continually faces into the direction of the wind. The turbines blades, perhaps each being 15m long for a 300 kW machine, are assembled by hand from a composite glass fibre material reinforced with wood or aluminium. The construction technique has been developed from that used for the hulls of modern sailing yachts. Blades may sometimes be made from steel.

Biomass Students should understand: • many different forms of biomass may be used as fuel • energy may be recovered as heat, fuel or electricity • the possibilities and limitations of recovering energy from urban solid waste.

A wide range of biomass materials can be utilised as fuel Wood and dried animal dung are traditional rural fuels, and continue to be used to a large extent in many regions of the world. In modern society there are a wide range of biomass materials that can be used as fuel. The main types are set out in the table along with techniques used for their use. Combustion of biomass is a carbon dioxide neutral process. Plants utilise carbon dioxide during the photosynthesis growing cycle. Carbon dioxide is then released as the material is burnt. Sustainably grown timber and energy crops are an energy resource that does not contribute to increases in atmospheric concentrations of carbon dioxide.

Renewable energy

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Biomass material

Description

How energy is utilised

Forestry residues

Branches and chippings from timber processing

Mainly used as boiler fuel

Agricultural wastes

Straw, poultry litter, sugar bagasse, etc.

a) Used as boiler fuel or for power generation b) Production of bioethanol for transport fuel e.g. use of sugar in Brazil

Energy crops

Fast growing biomass grown specifically for fuel e.g. willow or miscanthus

Power generation (only a few commercial examples)

Solid urban waste

Domestic and commercial wastes

a) Large scale incineration with energy recovery, used for power generation b) Recovery of methane gas from landfill sites, used for power generation and industrial heating applications

Sewage

Sludge from treatment of urban sewage

Anaerobic digestion of sewage sludge generates methane gas Used for power generation

Conversion technologies Most biomass applications involve the direct combustion of the material as fuel, sometimes in combination with fossil fuels. Other techniques, such as gasification and pyrolysis, produce a secondary fuel (gas and liquid respectively) that may be burnt in more conventional systems. Neither of these technologies are fully developed and commercially proven. Methane-rich biogas is evolved from anaerobic breakdown of waste material in sealed landfill sites and sewage digestors (Figure 12). This is proving to be a highly economic technology in many countries (China, India, etc.). Figure 12: Animal dung fermentation is a source of energy (gas) suitable for farms

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Renewable energy

Urban waste as fuel Urban wastes present a disposal problem. The two major disposal routes are burial in a landfill site, or incineration in large mass burn installations. Both techniques have associated costs and environmental impacts. Landfills should be carefully prepared and managed to prevent leaching of polluting materials into underground water courses, and to prevent dangerous build-up and release of methane rich gas. Incinerators are expensive to operate and release the pollution from the waste either as chimney emissions or within the ash which requires burial. Recently energy recovery has become more prevalent in both of these disposal routes as it reduces the overall cost of the disposal option per tonne of waste. Collection of landfill gas is simple if the site is appropriately designed and constructed, and the gas is burnt in large reciprocating engines which in turn drive generators. Heat is recovered from incinerators and used to raise steam for power generation in a steam turbine set.

Water power Students should understand: • the different ways in which energy can be harnessed from rivers and oceans • the advantages and drawbacks of hydro-electric power.

Water power technologies Large-scale hydroelectric systems are well established technologies for generation of electricity from water power (Figure 13). In some countries, for example Brazil and Norway a very high proportion of electricity generation is hydropower. Theses systems may use fast flowing mountain rivers, or be based on massive damming and flooding programmes. Figure 13: Hydro-electric power station

Renewable energy

37

There are many ways in which water power can be harnessed, some are commercial and proven whilst others, which use the power of the oceans, remain at the developmental stage but still show enormous promise. The main technologies are shown in the table. Technology

Description

Status of development

Large-scale hydro-electric

Massive artificial dams to generate electricity through turbines

Fully developed but problems with mega projects due to accelerated silting, public opposition and enormous financing cost

Mountain hydro-electric

a) Turbines on fast mountain streams

Fully commercial. Small-scale systems also being installed which have minimal environmental impact Pumped storage is useful for meeting peak electricity loads

b) Pumped storage systems (using cheaper night-time electricity to reverse the turbines and pump water back into a high reservoir) Low-head hydro

Hydro scheme using the energy from a river weir

Used in non-mountainous regions

Tidal power

Tidal barrage used where there is a high tidal range. Sea water is trapped behind sluices at high tide and released through turbines at low tide

Several commercial examples exist

Wave power

Wave energy is harnessed in two ways: a) floating platforms “bob” in the waves and the movement is used to drive a turbine b) devices in which waves breaking on the shore force air through a turbine at great pressure

Wave devices show great potential but have not proceeded beyond the prototype stage

Social and environmental impact Hydropower has many advantages, and at least for the large scale schemes, a few major disadvantages too. Where rainfall is seasonal, low water resources during the dry seasons can have severe impact on electrical capacity. This can present a significant problem where hydropower comprises a high proportion of a countryís generating mix. Large damming schemes have caused well publicised problems over displacement of local peoples, drying out of natural flood plains, reservoir silting, water disputes between neighbouring countries and the immense cost of financing such schemes. More local issues relate to the ability of fish to make their way upstream to breeding areas and visual impact in areas of outstanding natural beauty. Wave technologies have to contend with very aggressive environments and the cost of such technologies is likely to be high. The potential resource is virtually unlimited, and the research continues.

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Renewable energy

Geothermal Students should understand: • what geothermal energy is and how it may be harnessed.

Geysers and volcanoes Geothermal power makes use of the high temperatures found deep within the earth’s crust to provide heat energy. In a few places around the world, notably at the edge of tectonic plates, heat escapes naturally at the surface in the form of hot springs, geysers and most spectacularly volcanoes. In other areas aquifers run through hot rocks beneath the ground and this heat can be recovered through heat exchanging systems. Iceland is an excellent example of the use of geothermal energy where, in this very cold country, most of the houses are provided with heat from geothermal sources.

Hot dry rocks Tapping geothermal energy from deep below ground is a formidable technical task, and so far the economics have proved extremely expensive. The technique involves drilling two parallel bore holes down into the hot sub-rock. These bore holes are thousands of metres deep. Then controlled explosions are used to fracture the rock between the two bore to make a high surface area heat exchanger. Cold water is pumped down through one bore hole and is heated by the rock before passing back to the surface.

Suggested Activities - Renewable energies 

Organise a visit to a local renewable energy site, perhaps a traditional windmill or water-mill. Show the mill in operation grinding corn or in some other activity to demonstrate the power generated. Alternatively someone from the mill could be invited to visit the school and talk to the students about their work.



Get students to trace the origins of each renewable source back to the sun. Most so-called renewable are inexhaustible. Consider geothermal, continued extraction of heat will cool the rock, and it may take hundreds of years for the temperature to return naturally. Should geothermal really be considered as a renewable?



Local renewable resource assessment. Get the students to undertake a review of the potential for renewable energy in the local region. Use maps, meteorological data, library etc. to gather data on rivers and weirs, windy areas that might be suitable for turbines, agricultural and urban wastes. Students could write up their findings in the form of a report or strategic plan. Include maps and estimates of the percentage contribution that renewable could make to existing energy sources, consider electricity, direct heating and transport fuels. Ask students to identify what they think would be the main problems to developing their ideas in reality and how they would tackle these barriers.



Design and build project - vertical axis wind turbine. Get the students to make model vertical axis windmills and test various designs. This investigation requires a large quantity of plastic lemonade bottles, a few retort stands, plasticene, thumb tacks and an electric fan or hair dryer set at cold (Figure 14).

Renewable energy

39

Students fix a thumb tack point upwards to the top of the post of the retort stand using a lump of plasticene. They can then place the lemonade bottle upside down over the post and it should spin using the thumb tack as a bearing. They should then remove the lemonade bottle from the retort stand and decide how many sails their windmill will have and how large the sails will be. The lemonade bottle should then be cut and flaps bent outwards to make the required number of sails. The surface area of the sails can be worked out by tracing their shape onto squared paper and counting the squares. The bottle is then replaced over the stand on the bearing. Rotation Pivot

Figure 14: Diagram showing how the windmill is made

Air flow

Windmill sails

Plastic bottle

Retort stand

The air flow from the fan represents the wind. Students should count the number of revolutions of their vertical axis windmill each minute and record this figure as the result from the experiment. They should try this three or four times and calculate an average figure for the speed of their windmill. The students can then experiment by making windmills with different numbers of sails or the same number of sails of different surface areas. Pieces of lemonade bottle can be glued onto the windmills if extra sail area is required. Each windmill should be tested using the same fan set at the same air flow and held the same distance away. Each time the students should take an average of three or four readings. Students should be encouraged to compare their findings with those of others so that they have more data to consider when drawing their conclusions about the lemonade bottle windmills. At the end of the investigation students should be able to write a report about the most efficient design of lemonade bottle windmill. They should have collected sufficient data to draw some more general conclusions about vertical axis windmills. 

Biogas generators. Demonstrate the release of methane on decomposition of animal manure or compost by setting up a simple experiment (Figure 15). Use a flask with some manure and a similar amount of water (for the decomposition to work well this needs to be maintained at a temperature of 30-35°C, consider insulation of the flask). Collect the off gases over water using a plastic pipe and a test tube. Note that methane will not be released until all of the air in the flask has been used up - it may be around one week before methane can be collected.

40

Renewable energy

Figure 15: A laboratory biogas system Sealed stopper

Cotton wool (as filter)

Manure and water mixture



Glass delivery tube

Test tube to collect biogas

Water

Construction of a solar heating system. Students can build a simple solar panel using an old car radiator and a water circuit of domestic heating pipes. These pipes pass through a tank of water which the solar panel will heat up. A simple pump is connected to the system in order to circulate the water in the pipes and the radiator. The radiator should be painted black and mounted under a sheet of glass. On a sunny day it should be possible to demonstrate an increase in the temperature of the water in the tank. Alternatively a flat coil of black garden hose exposed to the sun can demonstrate the same principle. Run water slowly through the hose and measure the water temperature before and after passing through the hose (see Figure 16).

Figure 16: Demonstrating solar heating with a hose



Analogy between leaves and solar cells. Ask the students to draw comparisons between photovoltaic solar cells and plant leaves as collectors of solar energy. Consider items such as the need for large surface area, re-orientation towards the sun, surface texture and colour, how energy is energy stored.



Parabolic reflectors. Give students cardboard and aluminium foil to make simple parabolic reflectors. Show how effectively the device concentrates the sun’s rays by heating a small container of water (best if painted matt black) and measuring the temperature rise. These devices are also used for cooking food and heating water in remote locations. e.g. field trips.

41

Electricity

Main themes of this chapter  electricity as a clean and convenient means of transferring energy  the operating principles of a thermo-electric power station  the efficiency losses involved in generation and transmission of electricity.

Key information What is electricity? Electricity is a very convenient and controllable form of energy. It is easy to transport over long distances and enables us to supply energy directly into the home or factory for innumerable applications. It provides heating, lighting and mechanical power at the flick of a switch. It is also simple and accurate to measure its usage which is helpful in monitoring processes and charging for consumption. At the point of use energy does not create pollution. It is difficult to store, but chemical energy in batteries and potential energy, say in pumped storage reservoirs, are quickly converted back into electricity. Power transmission is one aspect of electricity but there are many others. It is used for communications (e.g. the telephone), our bodies nervous system functions due to tiny electrical charges, static electricity is an accumulation of charge (lightning, or the static on a balloon when rubbed on a woollen jumper). Electrical power is measured in watts, kilowatts, megawatts etc. See panel for examples.

UNITS OF POWER An amount of energy is measured in joules (J). This might be the total quantity of energy released by burning a lump of coal. The rate at which energy is used or released is measured in watts (W) and would be the amount of heat energy in joules that was given off per second by burning the coal. The watt is a small unit of energy compared to, say, the output of a power station so larger units are required. When recording an amount of electricity consumed the term kilowatt-hours is used (kWh) this equals 3,600,000 J. watts

W

a small clock might use 1W a household light bulb is typically 100W

kilowatts

kW

103 watts

an electric bar fire uses around 1 kW domestic family uses an average of 3 kW a typical wind turbine is 300 kW

megawatts

MW

106 watts

a school heating boiler might be 2-3 MW a small power station would be 500 MW

gigawatts

GW

109 watts

a large coal power station might be 1 GW Itaipu falls hydro-electric station in Brazil (the world’s largest) is 12 GW all of Russia’s power stations together have a capacity of 200 GW

terawatts

TW

1012 watts

total world energy demand is 12 TW the energy radiated from the sun is 400 million million TW (4x1026 watts)

42

Electricity

The thermo-electric power station The thermo-electric power station is simply a mechanism for converting one form of energy (fossil fuels or biomass) into another form - electricity. The fuel is burned in a large combustion chamber and heats water passing through pipes in the chamber walls. The fuel is injected together with combustion air through special burner nozzles. Oil is atomised as it enters the chamber and coal is crushed prior to combustion so that it may be blown in as a quickly igniting powder. The water is temperature is raised to form high pressure steam which is then expanded through the blades of a steam turbine, causing it to rotate at great speed. The turbine is directly linked to a generator which produces the electric current. In a natural gas fired power station gas is burnt directly within a gas turbine to drive the generator. These turbines work in the same manner as aircraft turbines but are much larger and designed for continuous use. Heat is recovered from the turbine exhaust and in high efficiency (combined cycle) installations is used to raise steam and drive a secondary steam turbine and generator. The generation process converts the chemical energy of the fuel into thermal energy (steam) which is then condensed through the turbine giving mechanical energy, and finally the generator converts this turning into electricity. Some energy is lost in each of these conversion processes (as heat or light or noise) and together these losses account for the efficiency of the system.

The distribution system Power stations are usually located as close as possible to primary resources. In a relatively large country the distance between the power station and consumers can be hundreds or thousands of kilometres. The electricity distribution grid, a network or cables pylons and transformers enables the electricity to be transported around a region (Figure 17). Figure 17: The generation, transmission and distribution of electricity

Electricity

43

Electricity is more efficiently transported at high voltages and typically different parts of the network would operate at 400 kV, 330 kV and 110 kV. The supply network uses lower voltages to feed into cities and towns, 35 kV and 10 kV are common. The electricity is further transformed down for end-users - 380 volts for industry and 220 volts for domestic consumers.

Efficiency losses Each of the many stages in generating and distributing electricity has associated losses. Much of this loss is inevitable (limited by fundamental thermodynamic principles for transferring energy from one form to another), but other losses are associated with the type of technology used, its condition and the way it is operated. Further non-technical losses come from the unaccounted loss of electricity from illegal connections. Many conventional coal fired power stations are only around 30% efficient and losses on distribution are often 10-15%. Modern natural gas stations (called combined cycle) and advanced coal stations (not yet fully commercial) are more efficient and over 50% is typical. A specific problem for the energy industry is the non-payment of energy bills by consumers - industrial and residential1. This has undermined the economics of the NIS power sector, debts for fuel remain unpaid, essential maintenance is neglected and the much needed investment programmes are slow to take effect.

Suggested activities - Electricity 

Assessing different energy sources. Ask groups of students to discuss the advantages and disadvantages of different energy sources for generating electricity (e.g. coal, gas, nuclear power, the various renewable energies). Prepare sets of discussion cards for each group. These are playing card size cards, each with one of the following statements written onto it. Student groups would be given the same set of cards but asked to assess different energy sources. Statements on the discussion cards.

Waste problems Environmenta l pollution Cost of installation

(1) See the TDP brochure “Improving residencial electricity service: a cooperative venture for a new billing system.”

• • • • • • • • • •

Cost of installation Environmental pollution Waste problems Lifetime of reserves Reliance on another country Found in our country Simple technology Greenhouse effect Expensive to develop We can export it

• • • • • • • • • •

Running costs Health hazard Reliability of energy supply Transport problems Expensive electricity Provides jobs Radiation Ozone depletion Smoke Too dangerous

The first task for the students would be to sort the statements into advantages and disadvantages for their particular energy source. Students would then prioritise each group of cards from the most advantageous to the least and from the most disadvantageous to the least. The only rule for this ranking exercise is that all members of the group should agree on the order of priority chosen. Once this has been completed the students can write a leaflet for their classmates about the advantages and disadvantages of their particular source of energy.

44

Electricity

Students should be provided with as many resources as possible for this part of the activity. These might include textbooks, newspapers, a library, the Internet and others. It might be appropriate to highlight local issues, or for an international perspective, to ask the students to produce the leaflet in English which will make the project even more cross-curricular. 

Making resistance heaters. Electrical immersion heaters, kettles and bar fires provide heat from resistance heating. Students can make small electric heaters by coiling wire around a pencil. Such heaters when connected up to a laboratory power pack (12 volts) will supply enough heat to warm up a beaker of water. Measure the change in temperature of the water over a fixed time period and monitor the electricity consumed with an ammeter (current) and voltmeter (voltage). From the readings it is possible to calculate the energy delivered by the heater two ways. One way uses the current and voltage: Energy released (Joules) = voltage x current x time in seconds The other way uses the temperature rise in the water: Energy released (Joules) = mass of water x temp rise in °C x 4.2 From these calculations students can work out the efficiency of the heater in converting electrical energy into heat energy. Where has the other energy been lost? Try using a variety of lengths and types of wire e.g. different gauges and various metals such as iron, copper or steel.

45

Reducing our energy use

Main themes of this chapter  the national and global importance of reducing our energy consumption  the concept of energy efficiency as a resource  opportunities to reduce the amount of energy used in society, both at a national level, and locally in schools and in the home.

Key information A need for efficiency Adequate and reliable energy supplies are of vital importance to any country’s social and economic security. In the NIS a lack of investment and revenue has led to an electricity system that is in need of rehabilitation and new investment to satisfy present demands. Much of the energy used is generated from highly polluting power stations, which are contributing to global climatic changes and to the detriment of peoples health. Nuclear power can have devastating consequences, should accidents occur, and leaves a legacy of radioactive waste that has to be stored safely for hundreds and thousands of years. Renewable energies offer cleaner energy but the cost is too high to make a significant impact now. One way of making a major contribution is to look at the way we use energy (Figure 18). Can we use less, in our homes, cities and industry? The answer is certainly ‘yes’ and the cost is significantly less than the investment needed in the supply system to generate additional electricity

Efficiency is a resource Energy efficiency can be seen as a resource. By reducing the amount of energy used, the investment needed in new power stations is reduced, or the oldest and most polluting power stations can be closed down. The dependence on fuel imports is reduced, and for countries that export primary energy more can be sold - in both cases the national economic balance of payments is improved. Figure 18: Individual behaviour influences energy consumption

46

Reducing our energy use

Many of the savings can be achieved through changing people’s habits, such as turning off lights, choosing to purchase more efficient household appliances, taking the bus to work rather than the motor car. Other savings require investment, and although the result may be a benefit over the lifetime of the investment the initial cost can present an important hurdle. Many actions and groups within society are helping to adopt the energy efficiency message. Architects have developed energy-saving houses, engineers are designing more energy efficient industrial processes, companies are appointing professional energy managers to examine and control energy use, and city planning is encouraging public transport to reduce energy and improve the quality of the urban environment.

Government actions Governments can undertake a range of information and economic actions to encourage the uptake of energy efficiency. Information actions

Providing technical information to industry. Promoting the need to save energy to the public. University courses and other training on energy saving techniques. Testing and labelling electrical goods with energy information.

Economic actions

Providing grants or other financial support for energy saving projects. Setting up energy saving projects to act as examples. Levy taxes to encourage energy or environmental actions e.g. a carbon tax.

Other

Establish organisations that can provide advice and assistance. Support new research activities, including international collaboration.

There are many aspects of society in which the energy used can be reduced, a few examples are given in this section, others are developed in the Suggested activities.

In the home There are many ways of reducing the amount of energy used in the home. Some are related to the building itself, to the types of fuel used and the appliances and other energy using devices in the home. Others are behavioural and relate to the way that people live and their awareness of energy wastage. Simple energy saving measures keep homes warmer without using more energy, and when energy is restricted makes better use of the energy available (Figure 19).

Reducing our energy use

47

Figure 19: Energy wastage at home

Building insulation Buildings should be well insulated to retain heat and to reduce the amount of heating required to maintain a comfortable temperature. Check for insulation in the loft and floor cavities and that the hot water pipes and storage tank (if present) are lagged. Windows are a major source of heat loss. Prevent draughts around doors and window frames by use of well fitting doors and draught excluder strips. Thick curtains will help to reduce heat loss through windows. Other measures to increase the house’s insulation are fitting of double glazed windows and lining internal walls with insulation. Houses built with a twin external wall can have the cavity filled with insulating material.

Heating systems Homes may be heated from a community heating network or with individual hot water, or electric systems in each dwelling. Community heating is more common in NIS and Eastern Europe than the West and could be a very efficient form of heating. But it presents little incentive for occupiers to minimise their energy use, thermostats are rarely used and individual energy use is not metered per apartment. Individual heating gives greater controllability and choice for users. Students could consider the advantages and disadvantages of the two types of heating system. Where individual heating systems are installed their efficiency, and safety, is maximised by regular servicing and cleaning. Radiators and hot air vents should not be covered, for example by drying clothes. Thermostats maintain rooms at the required temperature and should be turned down if a room is too warm, rather than simply opening the window! Baths use more hot water that showers, and water-saving shower heads will reduce energy usage further.

Electrical appliances Modern electrical appliances are considerably more efficient than models designed ten years or so ago. Energy labelling schemes are becoming more widespread. These provide information to the purchaser on the amount of energy the appliance will use, and the cost of this electricity over the items lifetime. This helps consumers to make a choice, it is better to perhaps pay a little more for a more efficient appliance that will save on the amount of electricity used.

48

Reducing our energy use

We can also make best use of electrical appliances. Refrigerators and refrigeratorfreezers are more efficient if defrosted regularly. Cooking is more efficient if pans are the right size for the electric ring and lids are used on pans. Simple actions such as only boiling the quantity of water needed also help to reduce energy use. Compact fluorescent lamps (CFLs) are available that use four times less power than conventional incandescent light bulbs and last around eight times longer. Consider replacing lights that are left on for more than a couple of hours each day with more efficient lamps. Switch off lights when leaving a room, and use lower power lights closer to working areas e.g. desk lights. Keep light bulbs, reflectors and shades clean to maximise light output. Recycling also helps to reduce energy consumption. Processing of plastic, metal and glass containers is energy intensive. Higher levels of reuse and recycling therefore saves primary energy.

Transport Collective transport systems are greatly more efficient than use of the personal motor car (Figure 20). Rail travel typically uses less than 10% of the energy consumed in road transport. Many countries have established schemes which provide incentives for people to reduce their car use and switch to collective transport. This has maximum effect in congested urban situations where collective transport has access to priority lanes and journey times are faster. Figure 20: Advantage of collective and public transport

100 passenger. km per litre

80 passenger. km per litre

20 passenger. km per litre

10 passenger. km per litre

Enforcing road speed limits energy consumption. This has several components, speeds closer to the optimum engine efficiency and reducing the effect of air and road friction. Simple aerodynamic styling for lorries can reduce fuel consumption by over 15%.

Reducing our energy use

49

Suggested activities - Reducing our energy use 

Organise students to carry out an energy audit of the school. Groups of students could investigate different parts of the school. Energy use is assessed as either lighting or heating. A light intensity meter can be used to measure lighting levels in various parts of each of the rooms and students can assess whether the lighting level is suitable for the activities carried out in each room. Find out whether there are Government standards for lighting levels in schools. Students could interview the school caretaker to find out how often lights are left on unnecessarily. The caretaker would also be able to explain to the students about the kinds of lights used in different rooms. Students can find out about the energy efficiency of the types of lights used. Students can calculate the heat supplied by a boiler and try to estimate how much of that energy was wasted before it reached the classrooms. Levels of insulation on pipework could be investigated and temperature differences in different parts of the pipework and school measured. Look for other heating appliances, e.g. electric fires, asses the condition of the windows and doors - are there draughts? is double glazing fitted? Students could interview the school caretaker about the efficiency of the boiler and losses through windows and doors being left open. Students could examine school plans and builders’ drawings to find out about standards of insulation in the walls and roof of the building. The energy audit would be written up as a report for the school principle. This should include data to support the findings and recommendations. The School Principal could be invited to a future lesson to discuss the survey findings and the survey’s recommendations. Alternatively the students could make a presentation of their findings to him/her.



Investigation into the insulation properties of various materials found in the home. Students could bring in curtain material, carpet, underlay, linoleum, polystyrene and woollen clothes. These materials are used in the home to prevent heat loss and to thus save energy. The students would need 250 ml beakers, heatproof mats, thermometers and an electric kettle to carry out the following experiment. Groups of students could test the different materials using the following procedure. First heat some water in the kettle and stand the beaker on the heat proof mat. Carefully pour exactly 100 mls of hot water into the beaker. Then wrap the beaker carefully in the material taking care to make sure that the thermometer bulb is in the water but that the scale can be read. The material should cover the top of the beaker as well as its sides. Take the temperature of the water at half minute intervals and record the results. When each group has finished their experiment they can draw a graph of their results. These graphs can be pinned up on the school notice board so that groups can compare and discuss their findings with the others. Students can write a report detailing the whole of the investigation.

50

Reducing our energy use



Students could carry out an energy efficiency survey on their homes. They could check to see whether their home has wall and roof insulation, or double glazing. They could find out whether the heating system is controlled by a thermostat. The students could do spot checks on whether the lights are left on unnecessarily. They could investigate the appliances that are used at home and find out how energy efficient they are. Students could also look at ways of motivating their families to save energy in the home.



The energy company perspective. Ask the students to consider themselves as managers within the electrical or heat utility supplying their neighbourhood. How would they run the company? What difficulties would they face? Would saving energy be important? Some of the issues they would investigate would be: repairs and maintenance needed, benefits of installing further energy metering, the billing systems, tackling non-payment of bills and illegal connections, energy losses from the system, improving levels of energy efficiency. Ask if a representative of the local utility would be willing to visit the school to answer the students questions or to take part in a discussion.



Local transport systems. Get the students to analyse the transport systems used in their neighbourhood. Carry out a traffic survey to estimate the mix of different forms of road traffic. Survey within the school, or to parents to find out what forms of transport are used: walking, cycling, buses, cars etc. Transport systems in other countries can be very different, with limited public transport and higher personal car ownership. Contrast a city in NIS with one in the USA. Examine and forecast trends in local transport use.



Travel choices. Making a journey, whether short or long, involves choices about the form of transport used. Get the students to consider the advantages of different forms of transport (walking, cycling, horseback, car, bus, train, boat, aeroplane, hot air balloon etc.) in terms of speed, practicality, comfort, cost and other factors. Ask them to assess journey plans for specific routes, perhaps between home and school, or between two local towns, or from their home to say, Paris in France. How long would it take and how much does it cost?

51

Energy in NIS countries

Main themes of this chapter  summary information on energy use in the NIS  comparison with energy use in other parts of the world  summary of the energy supply situation in NIS: the example of Russia.

Key information Energy Intensity The countries of the former Soviet Union have inherited an industrial base that is among the most energy intensive in the world. This is partially due to the high proportion of heavy and energy intensive industry, but also by historically low energy prices and limited incentives to try to use energy more efficiently. Industry in the NIS has not benefited from investment in modern technology and processes and some industries, for example the metallurgy sector, have an energy intensity calculated at twice that of accepted world best practice. Other industries are perhaps one third more energy consuming than their Western counterparts. Energy intensity has increased in the region by around 30% since 1990. This has accompanied a dramatic fall in economic and industrial activity, and reflects industrial enterprises operating at a fraction of normal output. In 1990, the distribution of energy use in the NIS region was as shown below. For comparison the energy use in a typical Western European country (UK) is also shown.  Energy consumption NIS, 1990: industry 48%, buildings 24%, transport 15%, agriculture and other 13%.  Energy consumption UK, 1990: industry 25%, transport 32%, buildings 29%, services 13%, agriculture 1%. Transport is generally more efficient in NIS compared to Western countries due to the lower proportion of private car ownership and greater use of public transport. Trains and buses are highly efficient compared to low occupancy car usage. Many countries in the West have instigated programmes and incentives to encourage a switch from private car usage to greater use of public transport. Current energy pricing and general policy in the NIS does not create incentives for renewable energies and it is unlikely that these alternative technologies could provide for more than a few percent of energy demand. The most interesting options include: • solar heating for domestic and industrial applications • biogas generation from landfill sites and sewage sludge • small hydropower • geothermal systems.

Energy use at home Energy consumption in homes and other buildings is found to be significantly higher throughout NIS than in Europe and North America. Some of the reasons are a lack of good insulation in buildings, poor efficiency of ageing municipal heating networks and the inability (or incentive) for individual families to control their heating use.

52

Energy in NIS countries

Electrical appliances are rarely designed for high efficiency in the NIS. In Europe many appliances are now marked with an energy label that gives clear advice to the purchaser on the appliance’s energy consumption. This is helping to eliminate the manufacture of the lowest efficiency appliances and to encourage consumers to think about the lifetime cost of electrical goods (i.e. including the electricity it will use) rather than solely the initial purchase price. Typical differences in efficiency for goods in the shops in NIS compared to Western Europe: 13% higher for refrigerators, 66% for TVs, 50% for electric ovens, 66% for vacuum cleaners, 54% for irons.

Suggested Activities - Data handling Energy statistics can provide many opportunities for students to practice data handling activities. Examples of the type of information that can be usefully collected are given in the previous sections of this handbook and in the box below. Energy statistics can be compiled from many other sources. 

Ask students to produce graphs, histograms and pie charts from the data.



Use the data with the students to practice Information Technology skills. Input data into computer databases or spreadsheets and produce a variety of graphical output presentations.



Get students to gather additional information from television and radio, newspapers, the library and the Internet to explore comparisons and trends in energy use and related issues.



Ask students to investigate and compare energy statistics in NIS countries. An example of the type of data that can be collected (for Russia) is given below.

Example: Energy supply in Russia Primary energy production Russia is extremely important in its contribution to global energy markets. Its natural gas reserves are the largest in the world, its coal reserves the second largest and oil the eighth. One third of the gas produced in Russia is exported, to markets within the NIS region and Europe. Russia supplies about a quarter of Western Europe’s gas needs. Energy exports accounted for 45% of all foreign income in 1996, which demonstrates clearly the importance of energy resources to the economy. Besides exporting fuels Russia has a massive domestic demand for energy, ranking second highest in the world. Only the USA has a larger energy consumption. The gas-fields are concentrated in the Siberian Tyumen region, and production is mainly from twenty giant fields in this area. The gas is distributed by an extensive pipeline network throughout NIS which links into the European systems. Coal reserves in Russia represent around 25% of known world resources. It is found in various regions notably in Donbass (bordering Ukraine), Pechora (Arctic) and Kuzbass and Kansk-Achinsk (Siberia). The majority of this coal is mined for Russian consumption, as it is a widely used fuel for power generation, industry and urban heating systems.

Energy in NIS countries

53

Russia’s oil reserves are found mostly in Siberia and Volga-Urals and much is exported, through pipelines, to Western Europe. A dramatic fourfold increase in car ownership since 1992 has put increasing strain on the Russia’s two refineries that produce high quality petroleum. Electricity generation Russia’s electricity is predominantly generated from fossil fuels in over 600 thermal plants. Together these supply 70% of all electricity generation. The remainder is sourced from hydro-electric stations (20%) and there are 29 nuclear power plants which account for a little over 10%. Demand for electricity is growing and new power stations are being constructed. The nuclear stations are in the Northwest, natural gas is predominant in the central and Urals regions; electricity in Siberia is generated from hydropower and coal; and coal is mostly used to the East. The older nuclear stations are nearing their forecast lifetimes and decommissioning is proposed however it is uncertain that adequate funding will be available to carry this out. Because of Russia’s size, many outlying areas are not connected to the electricity grid, and rely on small diesel power stations. Parts of Russia’s energy system experience severe financial difficulties with high energy losses, many non-accountable energy users and unpaid consumer debts. Cross subsidies on energy pricing have further eroded revenue whilst essential industries and military establishments are still provided with energy even when energy bills remain unpaid. The result is an energy system that has suffered the neglect of basic maintenance for many years and is in urgent need of investment. In the coal industry these factors have led to major labour strikes as miners’ salaries are not paid. Many mines have been forced to close.

54

Glossary

Acid rain

Rain, dew or snow which is more acidic than usual, produced by sulphur dioxide and nitrogen oxides given off by the combustion of fossil fuels.

Biogas

Gas produced by decaying material such as animal manure and other farm, household and industrial waste. The gas contains methane and can be used as a fuel to heat buildings or generate electricity.

Biomass

All types of organic (animal or plant) material. Biomass is a store of energy, which can be converted into other types of energy, e.g. wood, straw or animal dung can be burnt to produce heat and light energy.

Chemical energy

Energy stored in a substance and released during a chemical reaction. Fuels such as wood, coal, oil and food all contain chemical energy. The reaction when they are burnt (or digested) releases the energy, e.g. as heat and light energy.

Conservation of energy

When energy changes from one form to another (e.g. when fuel burns), the total amount of energy before the change is always the same as the total amount of energy after the change. The energy is always conserved. It cannot be destroyed.

Distillation

The process of separating a mixture of liquids by heating. The different liquids evaporate at different temperatures, the one with the lowest boiling point evaporating first. The separated gases are condensed back into liquids by cooling.

Dynamo

A machine which changes kinetic energy into electrical energy.

Fission

The splitting up of the nucleus of a heavy atom into two (or more) lighter nuclei. It releases huge amounts of energy.

Fossil fuels

Fuels which result from the compression of the remains of living matter over millions of years. Coal, oil and natural gas are all fossil fuels.

Friction

The resistance between two touching surfaces (or one surface and the air) when they move over each other. This slows down the moving object(s). Some of the kinetic energy changes into other types of energy,

Fusion

The joining together (fusing) of the nuclei of two or more atoms into one heavier nucleus. It releases vast amounts of energy.

Generator

A device which turns mechanical energy into electricity. The mechanical energy may be provided by an engine or a turbine.

Geothermal energy

The heat energy which is produced by natural processes inside the earth. It can be extracted from hot springs, reservoirs of hot water deep below the ground or from hot rocks in the earth’s crust.

Greenhouse effect

The warming effect produced when radiation cannot escape to the atmosphere or space. A good example is what happens in a greenhouse (hence the name). Short-wave radiation from the sun penetrates the glass of the greenhouse, and is absorbed by the plants, but the long-wave radiation that the plants emit cannot get back out through the glass. Carbon dioxide and other gases in the atmosphere act like the greenhouse glass.

Grid system

A distribution network of cables which carry electricity from power stations, where it is produced, to the cities, towns and villages of a country.

Glossary

55

Hydrocarbons

Chemical compounds which contain only carbon and hydrogen atoms. They are the dominant compounds in fossil fuels.

Hydro-electricity

Electricity which is produced from moving water. In a typical hydro-electric power station, the water turns turbines, which are attached to generators.

Insulator

A bad conductor, e.g. wood or plastic. These substances slow down the progress of electricity or heat energy.

Joule (J)

The unit of measurement of energy. One thousand joules equals one kilojoule (kJ). Kilojoules are normally used in measurements, since measured quantities are usually at least a thousand joules.

Kinetic energy

The energy of movement. The faster an object moves, the more kinetic energy it has. Also, the more mass a moving object has, the more kinetic energy it has.

Methane

A gas (a hydrocarbon) which is produced by organic (plant and animal) matter when it decays in the absence of oxygen. Natural gas is mainly methane.

Molecules

Particles which normally consist of two or more atoms joined together, e.g. a water molecule is made up of two hydrogen atoms and one oxygen atom.

Neutrons

Particles which form part of the nucleus of an atom (protons make up the rest of the nucleus).

Nucleus (pl. nuclei)

The central part of an atom, made up of tightly-packed protons and neutrons.

Photosynthesis

The process by which green plants make food (carbohydrates) from water and carbon dioxide, using the energy in sunlight. The food is a store of chemical energy inside the plants.

Photovoltaic cell

Another name for a solar cell.

Potential energy

Energy that is stored in an object due to its being within the influence of a force field, e.g. a magnetic or gravitational field.

Power

The rate at which energy is produced or used. It is generally stated as the rate of doing work or the rate of change in energy. Power is measured in watts (W). One watt equals one joule per second.

Primary energy resources The fundamental energy resources that may be converted by man into useful energy, includes fossil fuels, uranium, solar, wind, water and geothermal. Radioactivity

A property of the atoms of certain substances, due to the fact that their nuclei are unstable. They give out energy in the form of particles or waves.

Reactor

Part of a nuclear power station - the structure inside which fission occurs in millions of atomic nuclei, producing vast amounts of heat energy.

Renewable energy

Energy from sources which are constantly available in the natural world, such as wind, water or the sun.

Solar cell

A device, usually made from silicon, which converts some of the energy in sunlight directly into electricity.

Turbine

A device with blades, which is turned by a force, e.g. that of wind, water or high pressure steam. The kinetic energy of the spinning turbine is converted into electricity in a generator.