Better engines and fuels 'the quickest way to cut emissions’

Uptake of electric vehicles is too slow and the technology itself is not yet efficient enough to quickly make significant cuts to emissions, a new IMechE report has said.

The quickest way to cut emissions is instead to improve efficiency of internal combustion engines and switch to low-carbon fuels, according to Accelerating Road Transport: Decarbonisation.

Although the report says the roll-out of electric cars and charging infrastructure should continue, battery-electric vehicles only made up 1% of new EU registrations in 2018 and 0.2% of the entire fleet. Most of the other roughly 270m vehicles were petrol and diesel.

“There is a real opportunity to reduce the greenhouse gas emissions from those vehicles by adding biofuels and synthetic fuels,” said IMechE head of engineering Dr Jenifer Baxter to Professional Engineering.

“We’re saying ‘By 2040, we want to reduce or remove fossil-fuel-powered vehicles.’ But actually, we’re not really in a position where electric vehicles are going to pick up that slack, so what we need to do in the short term is to reduce our emissions by as much as possible, and B7 and E10 are two really good solutions for doing that quickly and actually relatively easily because they are already produced.”

The blended fuels, which combine diesel and petrol with up to 7% biofuels and up to 10% ethanol respectively, are already sold widely in the EU. Modern second-generation biofuels do not have the negative environmental impacts associated with first-generation biofuels, which have been criticised for significant land use. Hydrogen is another alternative, although it is currently made from fossil fuels.

Research into renewable or low-carbon fuels and improved internal combustion engines has been reduced recently because of increased focus on electric vehicles, said Steve Sapsford, co-author of the report and chairman of the IMechE Powertrain Systems and Fuels Group. A petrol vehicle running on 100% renewable fuel could reportedly produce 25% of the carbon emissions of today’s fossil-fuel-fired vehicles over its lifetime, but research is still needed and the solution could be a decade away.

The road transport sector accounts for about 27% of UK greenhouse gas emissions, and average CO₂ emissions from car sales has increased for the last three years thanks to a fall in diesel vehicle sales and the growing popularity of SUVs.

Although battery-electric vehicles are presented as ‘zero emission’, that is far from true in a full lifecycle analysis, the report says. Production – particularly of batteries – and electricity used to charge them means electric cars can be responsible for significant amounts of emissions.

“What we can’t really do is wait until somebody comes up with… ‘the right option’,” said Dr Baxter. “We won’t do anything, and then we will be in a position where we kick ourselves in 30 years’ time, saying ‘Well, if we just put a bit more effort into synthetic fuels, then we could have seen something quite different.’”

The report recommends:

“1. A move to E10 10% bioethanol in petrol pumps and B7 in diesel pumps, to help to rapidly decarbonise the many millions of internal combustion engines already running on conventional fossil fuels as soon as possible.

“2. The adoption of a life-cycle approach for all government policy. This takes a holistic view of greenhouse gas emissions and avoids the unforeseen consequences of backing particular technologies at the expense of exploring essential alternative and complementary approaches.

“3. Substantial investment (similar to that provided for battery-electric vehicles and charging infrastructure) in renewable and low-carbon fuel development and associated internal combustion engine technology levelling the playing field across low-carbon technologies. This will enable both growth in EVs and further immediate reduction in vehicle CO2 emissions with a managed transition to zero carbon.”

Download the report here.

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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.