If the trend of dynamic economic growth of the world economy continues unchanged in the future, global consumption of resources will more than double by 2050, according to statements by the International Resource Panel of the UNEP. The growth of electric mobility will signiﬁcantly change the use of materials for drive systems, batteries and power electronics in the automotive industry.
We have set ourselves the objective of reducing the primary raw material requirement for electric drive systems by 40% by 2030. In addition, we want to establish diverse recycling processes on the market for our high-voltage batteries.
We plan to increase the energy density of the batteries as part of our research and development activities and thus reduce the batteries’ total weight and the corresponding use of raw materials.
The production of vehicles requires great quantities of materials. Therefore, one of the focal points of our development tasks is to keep the demand for natural resources as low as possible. In particular, we attempt as early as the initial development stage to restrict the use of raw materials that are only available in limited quantities and that frequently have a larger environmental impact. An important role is played here not only by the economical use of resources but also by the remanufacturing of components and the recycling of used raw materials. As a result, the reconditioning and reuse of raw, process and operating materials has been standard practice at our plants for many years now. Thanks to these measures, we currently have a waste utilization rate of more than 90 percent.
Comprehensive life cycle assessment. Evaluating the environmental compatibility of a vehicle requires an analysis of the emissions and use of resources throughout the entire life cycle. This is done by means of a life cycle assessment, which examines the most important environmental eﬀects, from the extraction of raw materials and vehicle production to product use and recycling. At Mercedes-Benz Development, we use life cycle assessments to evaluate and compare diﬀerent vehicles, components and technologies.
Less weight, more recyclates and more natural materials. Our target is to make our vehicles lighter while continuing to reduce the environmental eﬀects of materials used in their production. For this, we are employing new lightweight materials and components on the one hand and increasingly using renewable raw materials and recycled materials on the other. The general principle here is to achieve more with less. For Daimler, this is the strategy of choice to conserve precious raw materials, especially those used in the area of electric mobility.
Intelligent lightweight construction can reduce vehicle weight without sacriﬁcing safety and comfort. In this context, the selection of materials as well as the component design and manufacturing technology also play an important role — not every material is suitable for every component. At 35 percent, the body-in-white accounts for the biggest share of the total weight of a vehicle with a conventional drive system. This is followed by the chassis at 25 percent, the comfort and safety equipment at 20 percent, and the engine and transmission at 20 percent. Thus the most eﬀective approach is to focus on the body-in-white.
In the case of hybrid vehicles, and even more so in the case of all-electric vehicles, the additional weight of the battery changes the weight proportions considerably. The battery in hybrid and electric drive systems can in fact account for approximately 25 percent of total vehicle weight.
Using recyclates to conserve resources. Recyclates are recycled plastics that come in whole or in part from processed production waste or old materials. The European End-of-Life Vehicles Directive 2000/53/EC speciﬁes utilization quotas for passenger cars and vans with a gross vehicle weight of up to 3.5 tons. In addition, it requires manufacturers to use more recycled materials during vehicle production in order to strengthen the markets for recyclates. As a result, the requirement speciﬁcations for new Mercedes-Benz models stipulate a certain minimum share of recyclates. The EQC (combined power consumption: 20.8-19.7 kWh/100 km; CO2 emissions combined 0 g/km)1 oﬀers a current example of how this works in practice. For example, customers can order their EQC with seat covers made of one hundred percent recycled PET bottles. In addition, some 100 EQC vehicle components are made from recycled substances or renewable raw materials such as hemp, kenaf, cotton, paper and natural rubber.
Renewable raw materials oﬀer us many advantages. For example, they can often help reduce component weight and the resulting products are generally easily recyclable. Moreover, their CO2 balance is almost neutral when their energy is recovered, because only as much CO2 is released as was absorbed by the plant during its growth. Last but not least, renewable raw materials as well as recyclates help reduce the consumption of fossil resources.
Consistently high recyclability. During the development process of a vehicle, we prepare a recycling concept for each vehicle model in which all of its components and materials are examined with a view to their suitability for the various stages of the recycling process. As a result, all Mercedes-Benz car models are 85 percent recyclable and 95 percent recoverable, pursuant to ISO 22 628. The key aspects of our activities in this area are:
- the resale of tested and certiﬁed used parts through the Mercedes-Benz Used Parts Center (GTC),
- the remanufacturing of used parts, and
- the workshop waste disposal system MeRSy (Mercedes-Benz Recycling System).
Removal of workshop waste with MeRSy. Our MeRSy recycling management system for disposing of workshop waste helps to collect and recycle or professionally dispose of waste material created during the maintenance or repair of our vehicles. For example a total of 29,452 tons of return parts and materials were collected in Germany and recycled in 2018. Around 1,533 tons of coolant and 645 tons of brake ﬂuid were reconditioned.
A new method for measuring resource eﬃciency. As economic growth continues, so does the burden on the environment, and the consumption of resources increases. Achieving more with less is therefore more than ever the order of the day. We have conducted several studies that address issues related to resource eﬃciency. In the ESSENZ research project, which received funding from the German Ministry of Education and Research, we helped to develop a holistic evaluation technique for assessing resource eﬃciency. The project has been completed and we are now using the new technique. In addition to raw material consumption, it takes into account other factors such as the security of the medium and longterm supply of raw materials as well as the fulﬁllment of social and environmental standards along the supply chain.
Resource consumption. Daimler consumes around 7 million tons of raw materials each year to manufacture its products. Some of these substances can be categorized as scarce or critical. We therefore monitor them closely and try to continuously reduce the amount of these materials that is needed per vehicle.
Resource use for alternative drive systems. Vehicles with hybrid and electric drives contain a particularly large number of valuable resources. This pays oﬀ if the entire life cycle is taken into consideration.
Life cycle assessment
In order to gauge a vehicle’s environmental compatibility, Daimler considers the emissions and the use of resources over the entire life cycle. This is achieved by means of a life cycle assessment (LCA), which records the key environmental impacts – from extraction of raw materials to production and use to recycling. As an example we show the life cycle assessment of a GLC F-CELL Plug-IN Hybrid (hydrogen consumption combined: 0.34 kg/100 km, CO2 emissions combined: 0 g/km, power consumption combined: 13.7 kWh/100 km)2 and of a Mercedes-Benz eCitaro bus.
GLC F-CELL Plug-IN Hybrid. The overall life cycle assessment for the GLC F-CELL shows the beneﬁts oﬀered by the model in terms of permanent locally emission-free driving and the high degree of eﬃciency displayed by the vehicle’s electric drivetrain. The assessment of the GLC F-CELL’s use phase analyzed two paths for the production of hydrogen and the electricity utilized to power the vehicle. First of all, if the electricity is generated from renewable wind and hydroelectric sources, the CO2 emissions can be reduced to nearly the level of the emissions that were required to manufacture the car. If the vehicle is recharged externally in line with the EU-28 electricity mix and if hydrogen produced from natural gas is used, the complete CO2 life cycle emissions of the GLC F-CELL will amount to 34 tons. Use of the H2 MOBILITY hydrogen mix (50 percent renewable) can lower CO2 emissions by 3.2 tons to 30.8 tons. The use of electricity and hydrogen produced exclusively from renewable sources makes it possible to reduce CO2 emissions to 16 tons.
In production, the drive components speciﬁc to the GLC F-CELL require a greater use of material and energy resources. The proportion of steel and iron is reduced by the omission of a combustion engine and transmission plus their peripheral units. On the other hand, the proportion of polymers, light alloys and other metals is increased.
Mercedes-Benz eCitaro Solobus. In 2018 for the ﬁrst time we investigated the Mercedes-Benz eCitaro and the Mercedes-Benz Citaro Diesel (OM 936) on the basis of ecological criteria. The eco balance hereby serves for internal comparisons regarding the eco-performance of the two vehicles. The study also caters to the requests of bus companies and cities that are very interested in such an ecological comparison and assessment.
We hereby always look at the entire life cycle with the phases of manufacturing, usage (comprising fuel production including AdBlue and electricity generation and driving) as well as end of life. We take a mileage of 600,000 kilometers over the life cycle for both buses. The life cycle assessments here are modeled on the basis of the SORT 2 cycle and a total life cycle mileage of 600,000 kilometers.
The assessment of the eCitaro analyzed two paths for the production of electricity in the use phase. If the bus is recharged externally using renewable hydroelectric sources, the complete CO2 life cycle emissions of the vehicle will amount to 91 tons. If the European electricity mix is used, CO2 emissions increase to 404 tons. However, the Citaro diesel model produces a total of 653 tons of CO2 emissions throughout its life cycle. Depending on how the electricity used to power it is generated, the eCitaro therefore produces CO2 emissions that are either 38 percent (European electricity mix) or 86 percent (electricity from hydropower) lower than those produced by a conventional Citaro diesel model.
2Information on power respectively hydrogen consumption and on CO2 emissions is provisional and has been determined by an external technical service for the certiﬁcation procedure in accordance with the provisions of the WLTP test procedure; the ﬁgures are non-binding and have been correlated with NEDC values. EU type approval and a certiﬁcate of conformity with oﬃcial ﬁgures are not yet available. The ﬁgures given above may deviate from the oﬃcial ﬁgures.