27 Aug 21

Why fleets need to base decisions on lifecycle carbon emissions

A true environmental focus needs to take into account the CO2 generated in producing batteries for electric vehicles

Switching to electric vehicles will not be enough for fleets to meet the the EU’s Green Deal target of reducing CO2 emissions from transport by 90% before 2050, according to new research.

The study, published in July by the International Council on Clean Transportation (ICCT), conducted lifecycle assessments (LCA) of carbon emissions from new cars with all different power trains, including internal combustion engines, plug-in hybrid (PHEV) technology and battery-electric (BEV).

Its results found the life-cycle emissions of BEVs registered today in Europe are 66%–69% lower than for a comparable petrol car, and that this gap will widen to 74%–77% by 2030 thanks to cleaner electricity. Carbon savings of this scale fall a long way short of the 90% demanded by the EU’s Green New Deal.

Lifecycle emissions

Similar in philosophy to total cost of ownership, an LCA of greenhouse gas (GHG) emissions takes into account the cradle-to-grave carbon dioxide emissions of vehicles, including the CO2 generated during the production and refining of raw materials and components, the manufacturing process, the driving phase, and end-of-life recycling.

Under this all-encompassing approach, the carbon footprint of electric vehicles rises significantly due to the emissions produced during the manufacture of lithium-ion batteries. As a result, the ‘breakeven’ point when an EV becomes lower emission than an equivalent internal combustion engine (ICE) vehicle ranges widely, depending on the vehicle and the carbon intensity of the electricity used to power its batteries – the payback period is much shorter if vehicles are recharged with renewable power.


Volvo Cars, for example, has published an environmental audit of its XC40, which reveals that the battery-electric Recharge model is responsible for 25.4 tonnes of CO2 before it leaves the factory, compared to 16.1 tonnes for the petrol version. As a result, the Recharge has to drive anywhere between 47,000km to 146,000km before its GHG emissions are lower than the ICE model, depending on whether it is recharged with wind power or a ‘global energy’ mix that includes electricity generated from fossil fuels.

This means that some electric company cars may still have a larger carbon footprint than their ICE equivalents at the end of their three- or four-year fleet life, although in every scenario their wholelife emissions will be substantially lower than a petrol or diesel model.

“When we move the analysis and comparison to overall lifecycle emissions, battery electric cars are two to three times cleaner in Europe - even when the battery is produced in China or when average grid electricity (not just renewables) is used to charge the car,” said Julia Poliscanova, Senior Director, Vehicles & Emobility, at Transport & Environment.

“The answer to fleets is clear - moving to lifecycle emissions will not change the fact that an electric vehicle is the cleanest technology to decarbonise fleets and wider road transport.”

PHEV fight back

However, a study published earlier this year by researchers at Lund University in Sweden said faster transport decarbonisation could be achieved by hybrids and PHEVs than BEVS, so long as they are powered by renewable electricity and biofuels (such as hydrotreated vegetable oil, made from forest and agriculture residues). PHEVs have smaller battery packs than BEVs, reducing the size of their GHG footprint during manufacture, and giving them an initial LCA advantage over BEVs.

The Lund University study compared the wholelife GHG of a Kia Niro hybrid, PHEV and BEV over 200,000km and found that if the hybrid and PHEV were fuelled by biofuels, they would produce significantly less CO2 than the BEV. The PHEV even has a slightly smaller carbon footprint than the BEV when fuelled with petrol.

The graph shows the life cycle CO2 emissions from a hybrid, PHEV, and BEV model when using gasoline, E85 (85% ethanol mainly produced from cereals and 15% gasoline), HVO (hydrotreated vegetable oil, made from forest and agriculture residues) and 2020 EU-28 electricity . The colours represent, from bottom to top, production phase emissions from the car and battery, usage phase emissions from the fuel and electricity, and end-of-life emissions. Source: Öivind Andersson, Pål Börjesson, The greenhouse gas emissions of an electrified vehicle combined with renewable fuels: Life cycle assessment and policy implications, Applied Energy, Volume 289, 2021

“The GHG emissions from the PHEV lie below the BEV in 100% electric mode. This is due to the significantly smaller battery pack reducing the PHEV’s production phase emissions. The gasoline-powered PHEV requires at least 49% electric drive share (EDS) to reduce the emissions below the BEV level. This is a typical EDS for the average PHEV customer. In practice, therefore, the PHEV carbon footprint is on par with that of the BEV when using 2020 EU electricity, even when operated with fossil fuel,” said the report.

Its verdict was echoed by a German study published in Scientific Reports, which tracked the real-life driving experience of 73,000 PHEV drivers in Germany and the US to see what proportion of miles were driven in electric mode.

“Over lifetime, the overall C02 emissions of our PHEV and BEV under investigation show similar values. When assuming short life times, the PHEV is advantageous, while for longer vehicle life time (above 10 years) the BEV becomes more attractive,” it said.

For fleet and sustainability managers committed to minimising the environmental impact of their vehicles there are perhaps four key takeaways:

  1. Vehicles with smaller battery packs have a smaller carbon footprint. This may give PHEVs the edge over BEVs for some fleet applications, if they can drive the majority of their journeys in electric mode.
  2. Make sure that PHEV drivers always recharge their vehicles (ideally with renewable electricity).
  3. The CO2 generated during vehicle manufacture plays a huge part in a vehicle’s lifecycle carbon emissions. Pressure OEMs to release this information – Mercedes-Benz and Volvo already do.
  4. If the market for renewable biofuels develops, it could play a valuable role in decarbonising road transport.

Images; Shutterstock, Volvo

Authored by: Jonathan Manning