California Gives Green Light to Space Solar Power

　　Energy beamed down from space is one step closer to reality，now that California has given the green light to an agreement that would see the Pacific Gas and Electric Company buy 200 megawatt (兆瓦)of power beamed down from solar-power satellites beginning in 2016.But some major chal lenges will have to be overcomed if the technology is to be used widely.

　　A start-up company called Solaren is designing the satellites，which it says will use radio waves to beam energy down to a receiving station on Earth.

　　The attraction of collecting solar power in space is the almost uninterrupted sunshine available in eosynchronous(與地球同步的)orbit.Earth-based solar cells，by contrast，can only collect sun Light during daytime and when skies are clear.

　　But space-based solar power must grapple(努力克服)with the high cost per kilogram of launching things into space，says Richard Schwartz of Purdue University in West Lafayette，Indiana， "If youre talking about it being economically viable or power of the Earth，its a tough go."he says.

　　Cal Boerman，Solarens director of energy services，says the company designed its satellites with a view to keeping launch costs down."We knew we had to come up with a different，revolu-tionary design，"he says.A patent the company has won describes ways to reduce the systemSweight，including using inflatable minors to focus sunlight on solar cells，so a smaller number cancollect the same amount of energy.

　　But using minors introduces other chaHenges，including keeping the solar cells from overhea-ting，says Schwartz."You have to take care of heat dissipation(散發(fā))because youre now concen-trating a lot of energy in one place，"he says.According to the companys patent，Solarens solarcells will be connected to radiators to help keep them cool.

　　Though Boerman says the company believes it can make space-based solar power work，it is notexpecting to crowd out other forms of renewable energy.Laws in California and other states requireincreasing use of renewable energy in coming years，he points out."To meet those needs，were go-ing to need all types of renewable energy sources，"he says.

　　16.Solar-power satellites will use radio waves to beam energy down from space.

　　A.Right

　　B.Wrong

　　C.Not mentioned

　　17.Solaren is going to design 200 solar-power satellites.

　　A.Right

　　B.Wrong

　　C.Not mentioned

　　18.Space-based solar cells could collect solar power only when skies are clear.

　　A.Right

　　B.Wrong

　　C.Not mentioned

　　19.One advantage of space-based solar power system is that it is economical.

　　A.Right

　　B.Wrong

　　C.Not mentioned

　　20.Inflatable minors are used to reduce the space-based solar power system.

　　A.Right

　　B.Wrong

　　C.Not mentioned

　　21.Space-based solar power will rule out other forms of renewable energy sources.

　　A.Right

　　B.Wrong

　　C.Not mentioned

　　22.Many countries will grant permission for the use of spaced-based solar power soon.

　　A.Right

　　B.Wrong

　　C.Not mentioned

　　答案：A C B B A A B C