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By Root 767 0

are now positioning themselves to exploit this massive future market: Nissan, General Motors, Toyota, Volkswagen, Honda, Ford, BMW, Tesla Motors, and Daimler are already or soon will be offering affordable electric vehicles. Tesla’s Roadster is a far cry from the electric vehicle’s caricature: This all-electric sports car can race from 0 to 60 miles an hour in under four seconds and has a top speed of 125 mph. And it is not just land-based transportation that will probably go electric: Electricity might also soon be the fuel of choice for small boats, which can more easily handle weighty stacks of batteries than cars, and where the strong torque provided by an electric motor could improve speed and maneuverability.

The only likely exception to the rule against biofuels is the urgent need to decarbonize air transportation, where low-carbon alternatives to liquid hydrocarbon fuels remain a distant prospect. While aviation has been demonized by environmentalists (myself included) in the past because of the climate change impact of aircraft emissions, in terms of fuel efficiency per passenger kilometer the latest large aircraft like the Airbus A320 and the Boeing 787 now compare favorably with small family cars. The reason why per capita emissions from an intercontinental flight are counted in the many tonnes of CO2 is the enormous distances covered: No one drives from London to Sydney. Reducing aggregate demand is not an option: Pleas by Greens for people to “give up flying” have found limited appeal to say the least, particularly given that most environmentalists I know continue themselves to enjoy the benefits of air transportation.31

Therefore, with over 2 billion people using air travel every year already, and rapid uptake in developing countries like India and China, technical substitutes for high-carbon aviation must rapidly be found. If they can be sourced fairly sustainably, biofuels look promising, particularly “second-generation” biofuels like algae that do not directly compete with food crops.32 British Airways has led the way with its pioneering commitment in February 2010 to build a plant in the U.K. that will convert 500,000 tonnes of waste material into 16 million gallons of jet fuel annually.33 This may seem like a large amount, yet it represents only about 2 percent of flights from London’s Heathrow Airport. This is the scale challenge of aviation, and demonstrates why biofuels may need to be almost exclusively reserved for air transportation—surface transportation must go electric.

However, where the electricity comes from to power the next generation of vehicles is of course vitally important. Electric cars charging up using coal power will deliver little or no benefit to the climate. Power stations using biofuels on a large scale, and gobbling up millions of hectares of land in the process, will be similarly disastrous. The best solution, as I showed in the climate chapter, will be a dramatically upscaled combination of renewables and nuclear, with the proportion of different technologies varying place by place. For the purposes of this chapter, however, it is the land-use implications of different energy options that are at issue—and here it is indisputable that nuclear wins hands down. The reason why is basic: Renewables work by harvesting diffuse energy like sunlight and wind over large areas, while nuclear fission delivers prodigious amounts of energy from tiny amounts of source material. Compared weight-by-weight, uranium 235 delivers a million times more energy than coal, which itself already represents chemical energy in a highly concentrated form. Just how much energy nuclear fission releases is described by Einstein’s famous equation E=mc2, where E is energy, m is mass and c the speed of light, about 300 million meters per second. Clearly even with a very small amount of fissionable material, multiplying it by the square of 300 million yields a very big number.

Antinuclear campaigners try to magic away this famous piece of physics by arguing that uranium mining and the disposal of radioactive