Battery electric passenger cars

Battery-powered passenger cars registered today have an advantage over conventional passenger cars in terms of their life-cycle carbon footprint (incl. vehicle manufacturing and energy supply) when using the German power mix. This applies in particular to urban and commercial vehicles.

The reduction of greenhouse gas emissions is a central political aim for the introduction of electric vehicles. In many cases, this can be achieved with current electric vehicles. In average use, a battery-powered car with a real range of approximately 200 km gives a CO2 saving of around 20% compared to a similar petrol car on the assumption that the current power mix is used – and taking account of the entire vehicle life cycle including manufacture and disposal. So the electric vehicle is more or less equal to a comparable diesel vehicle in terms of CO2 emissions. If we also consider that over the lifetime of the vehicle (assumed to be
13 years), the energy transition will ensure that the climate footprint for electricity generation will improve further, we can even assume an advantage of over 10% for an electric vehicle registered today compared to a diesel equivalent. These ratios change only marginally with the vehicle size.

Since our UMBReLA study in 2011, the environmental assessment of electric vehicles has improved in one key area. On the one hand, this is due to the ongoing development of lithium-ion batteries – nowadays we can assume that the battery will not normally need to be replaced during the vehicle’s life cycle. On the other hand, the proportion of renewable energies in the German power mix has increased. The carbon footprint of battery vehicles has improved slightly for this reason by comparison with our study on the further development and in-depth analysis of the environmental record of electric vehicles (commissioned by the Federal Environment Agency, 2015).

Climate footprint of battery electric vehicles in the compact class in average use, compared to conventional new vehicles.

The energy transition  is based on the average power mix over the service life of a new vehicle along with the assumption that the energy transition is set to continue (basis: “Current Measures” scenario from the Öko-Institut 2015). (IFEU 2017)

In the comparison between battery-powered and combustion-engined vehicles, there are differences between the distribution of emissions between the individual sections of the life cycle, alongside the overall emissions throughout the life cycle. For combustion-engined vehicles, the climate impact can be traced particularly to the direct exhaust emissions, in particular the carbon dioxide emissions (CO₂). Alongside this, the environmental effects of fuel provision (oil extraction, refining and distribution) are also relevant. These account for around 25% of the climatic effect of fuel combustion for petrol, and around 16% for diesel. Overall, the direct and indirect greenhouse gas emissions through vehicle use are responsible for around 80% of the climatic effect over the entire lifespan of the vehicle.

By contrast, the greatest contribution to environmental effects from electric vehicles comes from electricity provision (67%), which is of course likewise indirectly linked to vehicle use. The energy consumption of a medium-sized compact class electric passenger car is currently around 19 kWh/100 km on average. The efficiency of the powertrain is therefore mostly independent of the speed – by contrast with combustion engines.

Throughout the life cycle of an electric car, the manufacturing costs also contribute a proportion of over 30% to the climatic effect. Around 9.5 tonnes of CO₂ equivalents are released during production of a battery vehicle with a 200 km range; the figure is just under 6 tonnes for combustion-engined cars. Vehicle disposal and maintenance play only a subordinate role, which is sometimes because the preparation of recycled materials for vehicle manufacturing is added to the production of the vehicle.

Comparison of environmental effects for a battery vehicle (with a range of 200 km) and a combustion-engined vehicle:

• Greenhouse gas emissions  

  Environmental effect: Contribution to global warming over a period of 100 years

  Comparison: Electric vehicles benefit from the increasing proportion of renewable energies in the power mix, primarily in the usage phase. Although battery production generates relevant additional greenhouse gas emissions, there is in most cases a reduction in greenhouse gas emissions compared to conventional vehicles over the entire life cycle – even with today’s power mix.

• Acidification potential  

  Environmental effect: Contribution to the reduction of the pH-level of soils and water courses

  Comparison: The production of battery vehicles contributes a greater acidification potential through the overall higher use of materials and the use of certain materials (nickel, cobalt and lithium) within the battery.

• Eutrophication potential  

  Environmental effect: Beitrag zur Überdüngung von Böden 

  Comparison: In conventional vehicles, around 50% of the eutrophication effect is caused directly by exhaust emissions, with an added eutrophication effect through fuel provision. As neither of these factors apply to electric vehicles, they offer advantages in this area by comparison with conventional powertrains. However, vehicle production presents increased potential for environmental damage.

• Particulate emissions  

  Environmental impact: Contribution to the increase in particulate concentration (particle <10µm)
  
  Comparison: In the upstream chain, battery production generates high particulate emissions, with the result that the emissions are significantly higher when calculated over the entire life cycle than for conventional vehicles. During operation, however, battery vehicles cause no particulate emissions, which is of particular benefit in otherwise very highly polluted urban areas.

• Potential for summer smog  

  Environmental impact: Contribution to the formation of ground-level ozone

  Comparison: It is primarily petrol vehicles that contribute to summer smog formation with their hydrocarbon emissions when started cold. For battery vehicles, the contributions to this environmental effect arise during vehicle production and electricity provision. Overall they are significantly lower than for petrol vehicles, but are significantly higher than with diesel vehicles.

Comparison of resource requirements for a battery vehicle (with a range of 100 km) and a combustion vehicle:

• Energy consumption  

  Indicator: Primary energy requirements (cumulated energy demand in MY)

  Comparison: In this case (as for the climatic effect), the battery vehicle is roughly on a par with a diesel vehicle when recharged using the average available power, and is around 20% more efficient than a petrol vehicle. Using electricity from a completely renewable source significantly reduces both the greenhouse gas emissions and the primary energy requirements.

• Raw material costs  

  Indicator: The cumulative raw materials cost = the utilisation of material resources (mineral, metallic and biotic) in kg
  

  Comparison: The current significant disadvantages of battery vehicles in terms of raw material outlay are primarily due to battery production. Although there are likely to be increases in energy density in the coming years, the battery capacity per vehicle will also increase to reduce the current range restrictions. The raw materials outlay per battery vehicle will therefore drop gradually. Improved recycling can likewise make a contribution in this area.

• Water use  

  Indicator: Utilisation of fresh water (excluding cooling water) in litres

  Comparison: The largest proportion (90%) of water use occurs in vehicle production and its upstream chains. For a battery vehicle with a range of 100 km, it is around double that required for a conventional vehicle. This is primarily attributable to the production of electrolytes (lithium hexafluorophosphate) for the batteries. A complicating factor here is that the raw lithium is frequently obtained from areas where water is scarce (primarily the Atacama Desert in Chile). The reclamation of lithium and its compounds from old batteries could improve this situation.

• Land use  

  Indicator: Utilisation of land in m²*a

  Comparison: Land use throughout the life cycle of battery vehicles is only a fraction of the amount used for conventional vehicles. Land use is driven primarily by the manufacturing of the biofuel within the fuel supply.

• Criticality

  Indicator: Availability of raw materials from an economic perspective (supply risk and vulnerability)

  Comparison: Primarily cobalt and rare earth elements are identified as economically critical materials. Other critical raw materials could be substituted or are only used in small quantities. Increasing demand for electric vehicles in the future may lead to a rise in the criticality of metals. However, this would likely bring about changes to the way in which raw materials are obtained and to exploration activities, thus indirectly reducing criticality.

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Last Updated on Wednesday, 08 November 2017 23:01