Whitepaper Recycling Lightweight Automobiles

Whitepaper

Aluminium Axle parts made of magnesium Case-hardened steel Conventional steel

Recycling Lightweight Automobiles

Stichling, Hasenberg | PE INTERNATIONAL GmbH 30.03.2010

Recycling Lightweight Automobiles

Contents

Potentials of lightweight design for a sustainable mobility ............................................................................................................ 03

Executive summary . .......................................................................................................... 03

Recycling in the automotive lightweight design ..................................................... 04

Case study: spare wheel well .......................................................................................... 07

Conclusion ............................................................................................................................ 08

References, authors . .......................................................................................................... 09

About PE INTERNATIONAL ............................................................................................................ 10

Recycling Lightweight Automobiles

The Potential for a Lightweight, Sustainable Automobile Lightweight design is an important factor to reduce greenhouse gas emissions of automobiles. Nevertheless, not every weight savings inevitably reduces emissions. On the one hand, materials of lower weight need more energy to produce but, on the other hand, they reduce the consumption in the useful life.

Only a consideration of the entire life of the automobile can determine if the lightweight design is actually environmentally efficient. A life cycle analysis from the process of production to the end of life is the only method to give reliable answers to this question. There are no easy answers in this respect. Furthermore, legal regulations concerning limits of carbon dioxide and recycling rates do not only require lightweight materials but also materials which are easier recyclable.

Executive Summary

Weight savings are an important factor within the car industry to reduce the fuel consumption and therefore the carbon emissions. Because of expected mandated limits of carbon dioxide emissions, the requirements will even rise in this respect. The companies of the EU agreed upon the limit of carbon emissions of about 120g/km for 65 % of the new cars from 2012 on. In the following years, the aim will be that every new car will have this emission limit.

The installation of car parts of lower weight sets free further potential for savings by means of so called secondary effects. Through a car body of lower weight, further car parts such as motor, gear and tank size are able to be additionally adapted. Those secondary effects increase the reduction of consumption by a factor of 2 to 3 and therefore are relevant and should be used at any rate. A reduction of weight by 100kg can save fuel (petrol) to a maximum of approximately 0.35l.

Because of the fact that approximately 85% of the greenhouse gas emissions of the whole life cycle occur within the useful life, lightweight

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design is able to significantly contribute to the reduction of the emissions. Nevertheless, only a life cycle analysis can give information on the possibility of savings during the useful life to achieve a reduction of emissions. Materials of lower weight such as aluminium, magnesium, or carbon fibre cause higher energy expenditure in manufacturing than steel does. This higher input of energy then has to be able to be recaptured during the life cycle. In the best case, the lightweight design yields environmental returns early in the useful life. But even if this is not the case, the installation of a lightweight material can be useful. A higher energy expenditure of aluminium can be justified, if, for example an emissions credit can be received through recycling at end of life.

Therefore, a material’s ability to be recycled will be decisive in future. The government recognises this importance as well. The end of life vehicles regulation in force demands a material recycling rate as a weight percentage. This means that a more intensive use of lightweight components will also increase material recycling demands as easily recyclable materials (e.g. steel) are substituted by lightweight components.

Recycling Lightweight Automobiles

Recycling in the automotive lightweight design

In the recent discussion on climate protection in the 1990s, both countries and corporations settled upon the use of voluntary abatement goals as the main reduction tool. It is agreed upon the benchmark: in 1995, the Federal Government announced the goal of reducing carbon emissions nationwide 25% by 2005. The German vehicle manufacturers committed to reducing the average fuel consumption of vehicles within this time period by 25% as well. In 1998, the European Automobile Manufacturers’ Association (ACEA) and the European commission agreed upon an emissions limit for new cars of 140g/km of CO2.

This corresponds to a reduction of 25 % over the 1995 value (186g/km).

The maximum limit of CO2 for cars will be effective within the European Union from 2012 on The reduction of emissions by 25 % was an ambitious goal: possibly too ambitious. As events unfolded, none of these goals were achieved. As a result, voluntary emissions limits were eliminated as a solution. In December of 2008, the member states of the EU agreed upon mandatory limit values of 120g CO2/km. In this context, the limit for a car accounts for 130g/km and savings of further 10 g/km shall be achieved through other means, i.e. improvements in tires or use of biofuels. From 2012 on, 65% of new cars have to comply with the limit value. Afterwards, the respective percentage increases annually until, in 2015 when the limit value will apply to every new car. In case of noncompliance, the vehicle manufacturers will be levied with a fine.

From 2015 on, new cars within the EU are not allowed to emit more than 120g/km. In case of noncompliance, the vehicle manufacturers will be fined.

Through this regulation, the bar is set for the next years. Diverse approaches have to be

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followed in order to achieve the reduction goals and to avoid exceeding the limit. Weight savings as well as a reduction of fuel consumption are important factors in this context. In the scope of the European research project “SuperLIGHT-Car”, a consortium of 38 organisations has developed lightweight design solutions and has achieved convincing results through weight savings in the car body. They accounted for 35% within 2005 and 2009.

The research project SuperLIGHT-Car has shown that weight savings in the car body are realisable and justifiable on an economic basis.

By following a multi-material approach using modern hot-formed steel, aluminium, magnesium and fibre-reinforced plastics, 100kg could be saved in the reference car, a Volkswagen Golf.

Most greenhouse gases occur within the useful life Although nowadays trend-setting lightweight design solutions already exist in different car segments, the majority ofcar bodies are generally built as singular steel constructions. This results from current technical and economical restrictions.

SuperLIGHT-Car has proven technical and economic feasibility of lightweight multi-material designs.

Furthermore, it has kept the costs low at 8 Euro per saved kilogram. As shown in various studies, approximately one third of the overall fuel consumption of a vehicle is directly connected with its weight. The fact that most of the greenhouse gas emissions during the whole life cycle – approx. 85 % – occur within the useful life, shows the potential of the lightweight design to realise sustainable transportation. Other factors that support a sustainable transportation system are efficiency increases of drivetrain technology, drag reduction and improvement of the electricity management.

Recycling Lightweight Automobiles The fuel reduction value (FRV) indicates the energy savings Clear standards have to be set in order to be able to calculate the exact reductions of fuel consumption achieved by using the lightweight design method. The first step in the procedure is to calculate the mass-induced energy consumption over a defined distance (usually 100km) under a certain driving cycle (e.g. “NEDC”: New European Driving Cycle) and to relate it to the differential efficiency factor of the motor. Then, the consumption savings of a component is indicated by the FRV in litres of fuel per 100 kg and 100km. Because the FRV indicates a saving, the reference component has the value 0.

Consequently, the weight reductions cause a negative FRV and the weight increase a positive FRV. As a conclusion, the FRV calculates the absolute amount of savings – in litres of fuel – due to an alternative component of lightweight design but it does not calculate the relative savings compared to the former component.

Secondary effects significantly increase the potential of the lightweight design method If the vehicle’s weight decreases, the driving dynamics automatically increase. Nevertheless, a weight reduction should be used for further reductions of consumption instead of using it for better driving performance. In practice, this is realised by an extension of the gearing, reflecting a reduction of the engine capacity (downsizing).

Volkswagen takes these secondary effects into account with a factor of 2 to 3 (see Table 1). A reduction of the overall weight by 100kg therefore saves 0.35 litres of regular fuel each 100km on average; without those secondary effects the

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savings only account for 0.15 litres. Furthermore, a view on the reduction of consumption due to individual components does not fully reflect how the overall consumption of the vehicle can be generally reduced.

Fuel reduction values acc. to NEDC [l/100km*100kg].

Table 1

The reason is that due to a lower weight car body, further vehicle parts such as chassis, brakes and tank can be possibly downsized as well. If these measures are known, the system limit has to be correspondingly extended and the sum of all weight reductions has to be evaluated.

However, it would be too limited just to look at the fuel consumption.

It is too limited just to look at the fuel savings. The whole life cycle has to be taken into consideration in order to avoid distortions. This is the only way to quantify environmental benefits through lightweight design.

The actual environmental benefits and reductions of emissions can only be determined through analyses of the whole life cycle with a life cycle impact assessment (“LCA”). Lower weight material such as aluminium, magnesium, or carbon fibre needmore energy than steel in the process of production. Plastics are more difficult to be recycled. These factors are considered when the entire product life cycle is considered.

Recycling Lightweight Automobiles Environmental effects have to be taken into consideration during the whole life cycle

Recyclability – an important feature, especially in lightweight design

An LCA records all energy and material flow of a defined functional unit (e.g. part of the car body) from the production of raw materials to the end of life of the product (see illustration 1). In this way, dominant life cycle phases and tradeoffs of emissions and environmental effects within the life cycle can be recorded. Proposed new components first have to have their environmental impacts over the entire life cycle assessed before it can be determined whether a lower weight component is really able to reduce the carbon emissions. In this context, it is decisive to oppose the alternative components to the same functions within the LCA to avoid a falsification of the results.

Material recycling is an important factor in the lightweight design. Metals are particularly easily recyclable compared to plastics. A higher energy expenditure of aluminium can be justified, if a credit can be received through recycling (see Illustration 3). Furthermore, there will be a stronger focus on the used materials’ ability to be recycled because of the long-term goal of a closed cycle of material.

High energy expenditure in the process of production can be justifiable if a adequate recycling can be shown.

In the best case, the lightweight design is beneficial over the vehicle’s use, if for example higher energy expenditure within the material production can be recaptured due to a considerable reduction of weight over the useful life (see illustration 2). And even if the advantages do not arise in the useful life, the use of a material can be reasonable anyhow.

Lightweight design materials have to be recyclable. The end of life vehicle regulation of the European Union tightens this requirement further.

Through the effective end of life vehicle regulation, the government has already set standards for the next several years. Since 2006, at least 80% by weight of the vehicle has to be recycled at the end of life.

In 2015, this percentage will increase to 85%. The use of a weight percentage leads to a tightening of the recycling requirements because of the increasing use of lightweight design components.

Heavy steel, which is easily recyclable, is commonly substituted by lower weight materials which are more difficult to be recycled, such as plastics.

Expenditure for recycling Use Production

Illu. 1: schematic representation

of the LCA according to ISO 14044

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Illu. 2: carbon footprint without

credit note

Illu. 1+2

Recycling Lightweight Automobiles

Case study: spare wheel well

An assessment of greenhouse gas emissions over the whole life cycle was prepared for five different materials used to manufacture a spare wheel well. Without use of a recycling credit, the energy-intensive production of aluminium (Al) and magnesium (Mg) has a great effect on the total amount of emissions. Polypropylene (PP) and polyamide (PA) result in the lowest emissions over the life cycle because production emissions are relatively low and the low weight reduces the emissions in the useful life (St=steel).

If the materials are recycled at the end of the life cycle, a credit can be received for avoided production of primary material. The credit notes are especially high in the case of losed loop recycling of aluminium and magnesium. Therefore, the net emissions vary considerably in comparison with illustration 2. In this scenario, magnesium has the lowest emissions over the whole life cycle. Polypropylene and polyamide almost do not change because plastics are assumed to be incinerated with relatively low credit notes.

Expenditure for recycling Use Recycling – credit note Production Total, including credit note

Carbon footprint with credit note

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Illu. 3

Recycling Lightweight Automobiles

Conclusion

It makes no sense to establish general statements on what kind of material should be preferred or avoided within lightweight design. The goal and general of the LCA are decisive. Usually, a long useful life will benefit low weight materials, although they need a lot of energy during production. The ability to be recycled is a decisive aspect due to legal regulations because high energy expenditure in the process of production can be partly compensated by credit notes at the end of life if the material is recycled. Moreover, specific design requirements such as material strength and cost are as relevant as environmental requirements in shaping the choice of material. The lightweight design method achieves the best environmental performance if the impact on other components and assemblies is taken into account. Therefore, lightweight constructions should be included in the early process of development and be part of a master plan, instead of individually substituting single components.

The materials’ ecological relevance and their application can only be objectively proved under determined conditions, if the LCAs are carefully created and if they take into account the whole life cycle.

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Recycling Lightweight Automobiles

References, authors

Federal Ministry of Justice (2007): Regulation on the cession, redemption and sustainable disposal of end of life vehicles (End of life vehicle regulation). Berlin.

Federation of German Industries (2004): Voluntary arrangements and self-commitments. Survey of voluntary self-commitments and arrangements in the environmental protection. Berlin.

EurActiv (2008): EU achieves agreement upon CO2 emissions of cars. Report by 02/12/2008 on www.euractiv.com Koffler, Christoph and Rhode- Brandenburger, Klaus (2010): On the calculation of fuel savings through lightweight design in automotive life cycle assessments. International Journal of Life Cycle Assessment. 15-1, S. 128-135. Berlin/ Heidelberg.

Stichling, Jürgen (2008): Life cycle assessments on lightweight design of car bodies in the automotive industry. Lecture at the lightweight design-panel EuroLITE, Salzburg.

SuperLIGHT-Car-project (2009): SuperLIGHT-Car saves 35 % of weight concerning the car body.

Press release of the EU project SuperLIGHT-Car. Wolfsburg.

Picture credits

Cover graphics Up lite, Volkswagen AG Illustrations 1-3, PE INTERNATIONAL GmbH Table 1, Koffler, C. and Rohde Brandenburger K. (2010)

Authors

Jürgen Stichling (graduate engineer), Volker Hasenberg (agronomist)

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Recycling Lightweight Automobiles

About PE INTERNATIONAL Sustainability awareness is the road to long-term corporate operation and a vibrant environment.

PE INTERNATIONAL has been steadily guiding companies all over the world along this road since 1991.

Today, PE INTERNATIONAL is the international market leader in strategic consultancy, software solutions and extensive services in the field of sustainability. Serving market leaders around the world, PE has offices in Stuttgart, Vienna, Copenhagen, London, Manchester, Tokyo, Taipei, Perth, Bhilai, Boston, Wellington, Shanghai, Johannesburg, Istanbul and Kuala Lumpur.

PE INTERNATIONAL provides conscientious companies with cutting-edge tools, in-depth knowledge and an unparalleled spectrum of experience in making both corporate operations and products more sustainable. Applied methods include implementing management systems, developing sustainability indicators, life cycle assessment (LCA), carbon footprint, design for environment (DfE) and environmental product declarations (EPD), technology benchmarking, or eco-efficiency analysis, emissions management, clean development mechanism projects and strategic CSR consulting.

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