Debate over the Use of Renewable EnergyAusubel of Rockefeller University in New York, US says the key renewable (可再生的) energy sources, including sun, wind and biofuels, would all require vast amounts of land if developed up to large scale production - unlike nuclear power. That land would be far better (51) alone, he says. Renewables look (52) when they are quite small. But if we start producing renewable energy on a large (53) , the fallout (结果) is going to be horrible.Ausubel draws his conclusions by analysing the amount of energy that renewables, natural gas and nuclei (原子核) can (54) in terms of power per square metre of land used. Moreover, he claims that (55) renewable energy use increases, this measure of efficiency will decrease as the best land for wind, biofuels, and solar power gets used up.Solar power is much more (56) than biofuel in terms of the area of land used, but it would still (57) 150 square kilometres of photovoltaic (光电的) cells to match the energy production of the 1000 MW nuclear plant. In another example, he says (58) the 2005 US electricity demand via wind power alone would need 780,000 square kilometres, an area the (59) of Texas.However, several experts are highly critical of Ausubel’s (60) . John Turner of the US government’s National Renewable Energy Laboratory says that even if the US got all of its (61) from solar energy, it would still need less than half the amount of land that has been paved over (62) highways. Further, it need not (63) up additional land. The US could get a quarter of its energy just from covering rooftops of existing buildings, he says.According to Turner, the same "dual use" also (64) to wind power. "The footprint for wind is only 5% of the land that it (65) . Farmers can still farm the land that the turbines are on." Turner says looking solely at land use is an oversimplification of the issue. 65（）

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