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the power carried underneath the Mediterranean Sea via high-voltage cables. The area required would be 2,500 square kilometers of solar collecting mirrors, rising to 6,000 square kilometers if solar power were also supplied throughout the Middle East and North Africa as well as exported to Europe.64 This sounds like a lot, but it is equivalent to only the area of Lake Nasser above the Aswan Dam in Egypt and would create thirty times as much power as that dam does using hydroelectricity. The southwestern United States also has enormous solar potential, and the world’s largest solar thermal plant is located there: the Solar Energy Generating Systems plant in California’s Mojave Desert. As of October 2010, the California Energy Commission reported that an additional 34 large solar thermal plants have now been proposed, with a potential generating capacity of 24 gigawatts (a large coal plant might provide 1 gigawatt).65 However, there are land-use conflicts to be concerned with regarding this area, as Chapter 4 will show.

Perhaps the best place anywhere in the world for solar electricity is Australia, where a hot and sunny desert interior is surrounded by densely populated coastal cities. A square of outback 50 kilometers by 50 kilometers could theoretically supply all of Australia’s electricity demand using concentrating solar-power mirrors.66 In practice, many different solar thermal plants would be built inland from the major cities, reducing power transmission losses and spreading the infrastructure more widely. Solar hot-water systems are also an important technology for Australian households, although only 5 percent use them at present. The sun’s heat can also be used for cooling, thanks to a technology called absorption chilling. This makes additional sense, because the need for cooling is likely to be largest during the heat of the day, when the sun delivers the most energy. Shockingly, however, at the time of writing in April 2011, Australia has no operating commercial-scale solar thermal plants and remains 85 percent dependent on coal for its electricity. The country consequently has per capita carbon emissions higher even than the United States, at a shameful 20 tonnes of CO2 per person,67 and its government currently projects a 25 percent increase in emissions by 2020.68

The other key renewable technology to displace fossil fuels, and the one perhaps best loved by Greens, is wind. According to the Global Wind Energy Council, the world’s installed wind-power capacity is expected to have reached 200 gigawatts by the end of 2010, with 40 gigawatts added during that year alone.69 This is already making a significant dent in carbon dioxide emissions, especially if the alternative is coal. But the scale of the challenge remains enormous: In 2007, according to the U.S. Energy Information Administration, global installed coal-generating capacity totaled some 1,425 gigawatts, and is projected to rise to 2,360 by 2035.70 Wind is now a huge and growing business, with key movers in the industry like India’s Suzlon and Denmark’s Vestas among the big-league corporate players worldwide. In the U.S., General Electric is also a major wind turbine manufacturer. In the U.S., new wind installations fell by half in 2010 compared to the previous year, thanks to the recession and political wrangling over energy policy (or lack of it), even while the industry went from strength to strength in Europe and Asia.71 One of the big remaining hurdles in America is a straightforward lack of wires: New wind installations often lack grid connections to take their clean electricity to markets. In October 2010 Google Foundation became a partner in the Atlantic Wind Connection, a plan for a high-voltage undersea cable to bring large-scale offshore wind to the U.S. East Coast.72

In the U.K. onshore wind is increasingly being stymied by local opposition: According to one report, at least 230 local anti-wind farm campaigns now operate across the country, and approvals for new wind farms have fallen to an all-time low.73 From a climate change perspective,