An interesting letter in Ingenia, the journal of the Royal Academy of Engineering, from Professors David Cebon and Nick Collings of the Cambridge University engineering Department, expresses doubts about the potential for electric vehicles and points up the scope for improving conventional vehicles.

The potential difficulties associated with EVs have recently been recognised in a detailed report from the Royal Academy of Engineering: the need to decarbonise the electricity supply system; the high cost of EVs; the need for charging infrastructure; limitations of battery technology; the timescale for switchover; and the plans for greatly expanded low cost conventional car production in the developing world.

Cebon and Collings propose an alternative strategy, based on the advantages of conventional internal combustion engines and high energy density oil-based fuel: promote uptake of best practice technology to reduce ‘tank to wheel’ energy consumption by 30%; aim for a further 50% through refining conventional technologies, for instance vehicle mass reduction and engine downsizing (plug-in hybrids play a part here); incentivise improved hydrocarbons with lower ‘well to tank’ carbon emissions, such as biofuels, saving 20% carbon.  Overall, a 72% carbon emissions reduction is suggested as feasible within 20 years or so, which would go a good way to meeting an 80% reduction target by 2050. 

The key attractions of hydrocarbon liquid fuels for vehicles are the very high energy density and the existing distribution infrastructure, C&G persuasively argue.  Recognising this, it seems to me that the Plug-in Hybrid is the most attractive way forward, using liquid fuel as the range extender, while managing most regular shorter daily trips from off peak electricity charged overnight.