It is “inconceivable” that an electric vehicle driven in Great Britain could be more than polluting than its petrol and diesel equivalents, according to the latest Electric Insights report from Imperial College London and Drax.
This would require the carbon intensity of the power grid – currently averaging around 200g/kWh in 2019 – to more than quadruple to 850–950g/kWh – a level last seen during the 1960s.
“EVs have real potential to reduce our carbon footprint and help meet our net-zero carbon ambitions – despite some speculation about how clean they really are,” said Iain Staffell of Imperial College London.
“An electric vehicle in the UK simply cannot be more polluting than its petrol or diesel equivalent – even when taking into account the upfront ‘carbon cost’ of manufacturing their batteries.
“The carbon content of Britain’s electricity has halved in recent years and keeps on falling, whereas conventional engine vehicles have very limited scope to reduce emissions over their lifetime.”
The report says on a per-mile basis Great Britain’s electric vehicles currently emit a quarter of the CO2 belched out by conventional petrol and diesel cars. This proportion is expected to fall to just one tenth in five years’ time as the power grid continues to decarbonise.
Even if the emissions from battery production are included, EVs are now half as polluting as petrol and diesel cars.
Manufacturing each kilowatt-hour of battery storage emits roughly the same amount of carbon dioxide as burning through a full tank of petrol.
The report says small city cars such as the Nissan Leaf with 30-45kWh batteries can typically repay this carbon debt in as little as two to four years.
Larger, more luxurious vehicles such as the Tesla Model S with 90-100kWh batteries are in the red for much longer – between five and six years on average. Producing one of these packs can emit as much carbon dioxide as fifteen years of recharging or three round-the-world flights.
However, these figures are based on the current carbon intensity of the power grid. The payback periods could become much shorter as the remaining fossil fuel generation drops off the system.
Source: Electric Insights, Imperial College London and Drax