Options For Calculating The Long-term Sustainability Of Copper Use

Recommendation Paper Options for Calculating the Long-Term Sustainability of Copper Use

The Long-Term Sustainability of Cu Use:

Client: ECI (European Copper Institute)

November 2005

Author: Dr. C. Herrmann

PE Europe GmbH

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List of Contents

List of Contents List of Contents .................................................................................................................. 3 1

Introduction to Ecodesign ................................................................................ 4

2

Copper and Efficiency of EuP .......................................................................... 4

3

The Calculation of Sustainability Effects of Copper .......................................... 6

4

Recommendation ............................................................................................ 8

5

Literature ......................................................................................................... 9

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1 Introduction to Ecodesign Ecodesign of energy using products (EuP) gains an increasing level of awareness, not at least caused from the recently released directive for ecodesign of EuP (ECODESIGN EUP 2005). The core of ecodesign and thus the EuP directive is the quantitative description of environmental aspects of products throughout the entire life cycle with the aim of continuous improvement, i.e. reduction of environmental impacts. In other words, the life cycle phases of a product, which are mainly the manufacture, use and end of life (EoL) –including related transports, maintenance and service aspects etc.have to be investigated according to environmental effects. As the quantitative element is crucial, life cycle assessment (LCA) is one of the dominating methods to provide answers to the ecodesign requirements. Although the use phase often dominates the environmental impacts of EuPs, it is obligatory to investigate always all life cycle phases in order to avoid the shift of burdens. Oppositely, the increase of environmental effects in one life cycle phase or product component can cause a positive ecodesign effect, if the overall balance of the life cycle is better, i.e. causes lower impacts to environment in total.

2 Copper and Efficiency of EuP A very crucial aspect regarding to ecodesign of EuPs is the use phase. Energy is consumed for a specific purpose of the product, but due to the nature of physics, it is coherent to a specific loss of energy, which is not usable for the intended purpose. Regarding to the amount of energy and the respective life time of a product the use phase often dominates the environmental profile of those kinds of products. Consequential the use phase offers the most efficient option for improvement usually by reducing the related losses of energy1. Focusing on electrical power consuming EuPs, the efficiency can be improved by the reduction of electrical or mechanical losses. The latter, mechanical losses, mainly exist at dynamic products, such as motors or pumps, and could be reduced by design and material solutions, mostly aiming for reduction of friction. Electrical losses are at first sight rather a material question than a design issue. One aspect in the list of all property aspects of materials is the electric resistivity. The cross section and length, the temperature and the resistivity define the resistance, which causes electric loss, if a material conducts current. Looking closer to these resistance defining aspects the following options can be listed: 

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The selection of a material provides a certain resistivity, better to say a range of resistivity due to the temperature level; Table 2-1 shows some examples of metals.

Losses are the only variable improvement option as long as the energy demand is seen as necessary or unavoidable to fulfil the intended application; in this context the system view is out of scope, which might provide significant improvement potentials as well. Also in this paper it is no question of the necessity of existence and fulfilment of human needs, which would be rather a basic discussion of sustainability issues of human needs.

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Table 2-1

resistivity of some metals at room temperature (WWW 2005A) Metal,

micro-ohm-centimetre (µΩ*cm)

Silver

1.5

Copper

1.6

Gold

2.0

Aluminium

2.5

Zinc

5.5

Iron

8.7

Lead

19.3



The temperature influences the resistivity, which is a linear relation in a range upper or lower of room temperature. Only at very low temperatures close to zero Kelvin, superconductor effect can appear with zero resistivity, e.g. with lead.



The increase of cross section or decrease of length, e.g. of a wire or cable, can lower the resistance.

It can be concluded from these aspects, that not only the selection of a material but also the design of a cable, e.g. cross section and length, can lower electric losses. The aspect of temperature is quite complex and will not be discussed further, because usually the surrounding temperature and rise of temperature due to resistance define the resulting temperature of the conductor. The effect for example of superconductors is still a matter of research with unquestionably high potential. But today, still the effort of cooling offers hardly a positive effect relating to the reduction of losses. Consequently an EuP with a reduced electrical loss saves energy during use, but also causes various effects during manufacture. Ecodesign has to take into consideration the environmental profile of materials, which is symbolised in Table 2-2 on behalf of CO2 emissions per kg produced material2. Certainly the economic values are also a viable aspect of consideration.

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Certainly further treatment of materials such as making wires or sheets must be included in an ecodesign study, which is not matter of this paper

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Table 2-2

CO2 emission and economic value of some metals (GABI 2005, WWW 2005B) Metal,

kg CO2 emissions per kg produced material (G ABI 2005)

ca. value per kg of material in € (www 2005b)

Silver

365

200

Copper

2.4

4

Gold

ca. 30 000

12 500

Aluminium

13

2

Zinc

2.7

1.5

Iron

1.8 – 3.4 (whether mechanical or Si-steel (dynamic or static))

0.5 up to several € depending on quality and alloy

Lead

1.7

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Based on the resistivity values of Table 2-1 and information of Table 2-2, it can be seen that copper provides the best solution in the trade off between low resistivity material and its ecological as well as economic value, which is quantified for example from design solutions, such as demand of mass of a material. Assuming copper has already been selected as conductor material, which often is the case, there is still an improvement potential in the selection of cross section or length. The change of those design aspects, e.g. a larger cross section of copper wire, may also cause changes of residual product parts possibly containing other materials. Thus, ecodesign must take into regard not only the environmental profiles of the selected materials, but also consequential changes in the design of the entire product. The following chapter will provide an overview of alternative calculations how the environmental benefit of the use phase can be allocated to the burdens of manufacture due to additional material demands.

3 The Calculation of Sustainability Effects of Copper Typical examples, of how to improve the use phase (reduction of losses) of a product by the use of more material during manufacture, are electric motors and transformers. Those products mainly consist of three basic materials, which are:

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

Copper, which is always used as active material; usually the wires are made of copper



Aluminium, which is either used as active material alternatively to the copper wires or is rather a passive3 (supporting) part of the product, e.g. in case of motors as typically the rotor is made of aluminium



Steel, which is used for passive parts in the sense of support of active parts, such as silicon-steel with improved magnetic properties (dynamo or trafo steel), or simply mechanical steel mainly for constructive and static parts.

Active and passive in this context means either the material, which is the conductor material and thus directly causes loss reduction during use (active), or material, which supports the active parts or is even for static/housing reasons (passive)

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Other materials, which are certainly also applied in those products, such as insulators, cooling agents etc., usually do not influence the use phase and are of minor significance in ecological and economic matters. Thus they are not considered here, but principally should be regarded as additional passive product parts. Assuming the total number of installed transformers was improved by additional demand of active material, it would lead to a decrease of environmental effects by their use (use phase improvement). But more active material leads to higher environmental impacts of this material plus the additional demand of the passive materials. Generally the following approaches are possible for an ecodesign consideration: 1) The active material causes the improvements during use and therefore is the only reason of the improvements; thus the entire benefits are calculated against the impacts only of the active material. 2) The active material causes the improvements but causes also the additional demand of other, passive materials; thus the entire benefits are calculated against the impacts of the active material, which are increased by the impacts from all other, passive materials (rucksack principle). 3) All additional materials are equally treated and thus the benefits are allocated with an allocation factor based on weight (x, y and z are masses of additional demand of materials, the allocation factor is x/(x+y+z) for the material x, y/(x+y+z) for material y and z/(x+y+z) for material z). 4) Equally as 3), but the allocation factor does not base on weight but on other criteria such as economic value, environmental impact or other criteria; thus the x, y, and z is the weight multiplied with the chosen criteria of each material per kg. The situation is a typical question of allocation and how to define an allocation factor. In principle ISO14041 demands to avoid allocation whenever possible. If avoidance is not possible a physical factor shall be used to quantify the allocation factor. If this is not applicable other factors such as economic values may be taken (ISO 14041). Many discussions have been taken and still take place on allocation in LCA, e.g. EKVALL 1999 provided a profound base of options. But eventually it must be stated that always the selection of an allocation is a subjective decision (EKVALL 1999, HERRMANN 2004). The following considerations have to be taken: The approaches 1) and 2) avoid allocation and follow an intended principle in LCA, which is the cause related calculation (EKVALL 1999). But 1) is not acceptable, as it does not include at all the obviously necessary additional impacts of the passive materials. It would not be in accordance to the principle of ISO 14041, that “the sum of the allocated inputs and outputs of a unit process shall equal the unallocated inputs and outputs of the unit process”. Option 2) is methodologically appropriate, as the active material relates to the benefits and the consideration of the impacts of the other materials are also covered by the rucksack principle. But from the perspective of the rucksack materials there is no benefit given, although they are somehow necessary. This option equals an undividable system view, at which the system is the sum of all additionally applied materials. The approaches 3) and 4) are typical allocations. 7

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Option 3) is not cause related as the passive materials, assuming to be considered solely, would not cause any kind of benefit, but get calculated a partial benefit. Also option 4) is not cause related as the kind of allocation factor does not provide a better or more applicable relation between cause and effect as it is usually the matter at allocations. The effect here is simply the cause for use phase benefit, which is related to active materials.

4 Recommendation Based on the described options it seems most appropriate to take option 2), the rucksack principle, if a clear differentiation of active (cause) and passive (rucksack) material can be taken. It would follow the ISO principles to avoid allocation and the cause related modelling. If more materials somehow contribute actively to the cause (reduction of use phase loss), it should be detected how much cause is due to which material. Then the respective benefits can be set in comparison to the individual impacts. If this is not possible due to missing physical reasons, the benefit should be allocated to the active materials based on option 3). As the physical property „mass‟ is adequate, there is no reason for an alternative allocation base. If in the case of more active materials also passive materials have to be considered it should be tried to detect, which and how much mass of passive material is possible to relate to a respective active material, in order to apply the rucksack principle. If also this is not possible the respective masses of the passive materials should be allocated as rucksack to the active materials on base of allocation by weight of active material4. Finally, if no clear distinction between active and passive material is possible at all, option 3) should be applied to all materials equally. The cause relation is not clear and thus the principle of cause related modelling is not applicable. Another base than „weight‟ for quantifying the allocation factor would not improve the allocation system at all. Consequently option 3) is the best trade off for this kind of indefinable situation. To follow further ISO 14041, which states regarding to the principles of allocation: “whenever several alternative allocation procedures seem applicable, a sensitivity analysis shall be conducted to illustrate the consequences of the departure from the selected approach.”, it is recommended to conduct studies showing the respective effects of the different approaches, e.g. applied on motors and transformers. Finally it shall be clearly stated that these recommendations do only apply to the delta of additional material for a delta of benefit. The cause and effect related aspects of entire products is not matter of this discussion.

4

The weight of the active materials serve as allocation base also for the passive materials, which after allocation are calculated as rucksacks.

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5 Literature ECODESIGN EUP 2005

Directive 2005/32/EC of the European Parliament and of the council establishing a framework for the setting of ecodesign requirements for energy-using products and amending Council Directive 92/42/EEC and Directives 96/57/EC and 2000/55/EC of the European Parliament and of the Council, Brussels, 6. July 2005

EKVALL 1999

Ekvall T.: System Expansion and Allocation in Life Cycle Assessment, Dept. of Technical Environmental Planning, Chalmers University of Technology, Göteborg, Schweden, 1999

GABI 2005

GaBi 4: Software and database for life cycle engineering. IKP, University of Stuttgart and PE Europe GmbH, LeinfeldenEchterdingen, 2005

HERRMANN 2004

Herrmann, C.: “Ökologische und ökonomische Bewertung des Materialrecyclings komplexer Abfallströme am Beispiel von Elektronikschrott – eine Erweiterung zur Ganzheitlichen Bilanzierung“, Dissertation, Universität Stuttgart, Institut für Kunststoffprüfung und Kunststoffkunde, Shaker Verlag, Stuttgart, Januar 2004

ISO 14041 : 1998

ISO 14041 Environmental Management – Life Cycle Assessment – Goal and Scope Definition and Inventory Analysis

WWW 2005A

http://my.execpc.com/~rhoadley/magcondb.htm, last access Nov. 2005

WWW 2005B

http://www.lme.co.uk/dataprices_daily_metal.asp, last access Nov. 2005

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