Transport Technology: Electric Cars and Alternatives

Scientific Alliance Newsletter (UK)- June 26, 2009

A few years ago, the hydrogen fuel cell was widely seen as the favoured way to replace the internal combustion engine. The selling point was that only water vapour would come out of exhaust pipes; cars journeys would have zero carbon emissions. Reality, as always, was rather more complex. Despite the perceived advantages, hydrogen-fuelled cars face enormous challenges if they are ever going to move beyond the demonstration stage.

Generating, distributing and storing hydrogen on a large scale is horrendously difficult, and the infrastructure investment necessary is mind-boggling. And, above all, hydrogen is simply a carrier of energy, which must be produced using low-carbon sources of power to offer any advantage in overall emissions reductions. This itself means a huge investment in (intermittent) solar, wind, tidal or wave power, in new nuclear capacity, or in coal stations fitted with (as yet unproven) carbon capture and storage systems.

Not surprisingly, battery-powered cars have gradually become the preferred option. They of course also only become a low-carbon option if appropriate power generation systems are in use. Looking at the bigger picture, the inefficiencies and losses at each stage of the system – electricity generation, transmission, battery charging, car use – make the argument for moving to electric cars less attractive. It is only if carbon reduction rather than overall saving in energy use is the main driver that a concerted move in this direction makes sense.

The other main issues with electric cars are their range and affordability. It is certainly possible to make a high performance battery-powered car with a reasonable range (the Tesla Roadster), but the cost is high and this is hardly for the mass market. All other current or close-to-market models have a very limited range, making them really only suitable for urban use. And the UK government would not be offering purchase grants if they were economically competitive.

But let’s not be too negative: this is a new technology (well, actually improved, as some electric vehicles have been with us for many years) which deserves to be given a chance. And that’s exactly what is happening with a new scheme just announced by Paul Drayson, the UK science minister. About 340 electric vehicles will be leased to members of the public in eight places around the country. The stated intention is to encourage R&D by car companies to kick-start widespread adoption of the technology which, say the government, could cut the 22% of national carbon dioxide emissions generated by road transport by half.

Maybe, but there is clearly a long way to go yet. Charging infrastructure is one big issue, with public charging points being installed in some of the trial areas. A spokesperson for Mini UK, one of the car suppliers, also pointed out that charging from a normal household power point would take over 10 hours (and anything with a significantly longer range would need much longer) so they are hoping to get the local electricity company to install a 32 amp supply in the homes of participants. This is only possible for houses with fairly modern wiring.

But the challenges to a substantial rollout of electric cars in towns seem more readily overcome than those impeding a similar introduction of hydrogen as a motor fuel. In the meantime, though, what would be the costs and savings in energy and carbon dioxide emissions if all road vehicles were to be powered by the latest generation of highly efficient diesel engines?

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