By far the biggest hurdle to expansion of solar power is cost. Solar panels are usually made of silicon, and the world is runnin

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问题    By far the biggest hurdle to expansion of solar power is cost. Solar panels are usually made of silicon, and the world is running out of it. Yet the economics of solar may be about to change.【F1】Aided by hefty infusions of venture capital in recent years, solar companies are on the cusp of developing new technologies that generate more power using less silicon, prompting predictions that costs for solar systems could be cut in half within the next three years.
    That process might be accelerated with a little more nurturing from the federal government.【F2】This year, the Energy Department will spend $ 303 million on research and development for nuclear power and $427 million on coal, while forking out a paltry $159 million on solar. That may be because the country gets less than 0. 01% of its electricity from the sun, but it doesn’t reflect solar power’s potential.
    Enough solar energy hits the Earth in an hour to supply all the world’s electricity needs for a year. A 100-square-mile area of Nevada, if equipped with solar devices, could supply the U. S. with all the power it needs, according to the Energy Department. Again, such pronouncements don’t address the real-world practicalities.【F3】But given that neither coal nor nuclear power is a practical solution to global warming, U. S. research priorities are badly skewed.
    If roof-mounted solar panels aren’t quite ready for prime time, concentrated solar power systems might soon become a hit.【F4】These are usually arrays of reflectors installed in sunny areas like the Mojave Desert, where they concentrate sunlight to heat a liquid that turns to steam and powers a turbine.【F5】The Solar Energy Generating Systems, an installation of nine solar arrays in the Mojave that puts out 354 megawatts, has been considered the biggest such plant in the world, but it won’t be for long. Five more Mojave plants are scheduled to come on line in the next few years; together they will generate more than 1 , 000 megawatts. These projects have to jump many of the same transmission hurdles as wind farms.
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答案通常在阳光充足地区,比如莫哈韦沙漠,安装大量阳光反射板,聚焦阳光加热液体,使其变成蒸汽,推动涡轮。

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