A new environmental report has challenged perceived wisdom into electric and hybrid vehicles by claiming that they emit fewer emissions
over their lifecycle than diesel cars.
The Low Carbon Vehicle Partnership study found that electric and hybrid cars create more carbon emissions during their production than standard vehicles – but are still greener overall thanks to their lower tailpipe emissions.
For example, a typical medium-sized diesel family car will create around 24 tonnes of CO2 during its life cycle, while an EV charged from the National Grid will produce around 18 tonnes during its life.
For a battery-powered EV, 46% of its total carbon footprint is generated at the factory, before it has travelled a single mile, compared to 23% for a conventional car.
The findings provide a fillip to EV manufacturers by dispelling “the myth that low carbon vehicles simply displace emissions from the exhaust to other sources”, said Greg Archer, LowCVP managing director.
However, the report contains several assumptions. It compares electric vehicles available today with a hypothetical diesel car in 2015 – the point at which EVs are expected to become mainstream.
In addition to predicting likely CO2 emissions in 2015, the calculations also assume that diesel cars will be fuelled using a 10% ethanol blend.
Emissions from battery production equate to nearly half of the overall CO2 emissions during the vehicle production process.
This calls into question battery life: if a replacement is necessary during the lifecycle, it could make the EV more polluting.
The LowCVP accepts that replacing the battery during a vehicle’s useful life would “significantly negate any carbon savings”.
However, it believes this is unlikely for any mass produced vehicles and says it has not been the case for the well-known battery electric-hybrid vehicles in series production.
Nissan says that after four years it expects its batteries to retain 80% of their power output and, rather than replacement, the manufacturer will “recondition” the battery to reinstate its full output.
“Vehicle manufacturers have invested heavily in ensuring that the battery will last for the useful life of the vehicle,” said Professor Neville Jackson, chief technology and innovation officer at Ricardo and LowCVP chairman.
The report is flawed on its lifecycle calculations, which do not take into consideration fleet mileage.
The calculations are based on 150,000km (93,210 miles), roughly 10 years for a privately-owned car.
A typical fleet car would reach this figure within five years and, once sold into the used market, could easily continue to 150,000 miles.
It’s questionable whether an electric vehicle, with its much lower anticipated annual mileages, would have so long a life.
If so, for real-world mileage, the lifecycle CO2 emissions of the diesel car would be lower.
The LowCVP report has chosen to make comparisons based on typical usage for the electric vehicle, which clearly gives it the edge.
More on page two...