Here comes the sun.When "Reaching for Rays: Scientists work toward a solar-based energy system" (SN: 5/26/07, p. 328) says that "scientists don't expect traditional silicon-based solar cells to become competitive with fossil fuels," one has to ask, "Ever?" Can anyone accurately predict the future price of polysilicon or of fossil fuels? PETER A. KACZOWKA, LENOX, MASS. Your article notes as a put-down put·down or put-down n. Slang 1. A dismissal or rejection, especially in the form of a critical or slighting remark: "Such answers were, perhaps still are, a . . . that it would be necessary to build a 1-gigawatt nuclear-fission plant every day and a half for the next 45 years to meet anticipated global electrical demand. A similar calculation indicates that building an equivalent solar capacity would require that we coat about 60 square kilometers of desert with photovoltaic The generation of voltage by a material that is exposed to light in the visible and invisible ranges. See photoelectric and photovoltaic cell. material every day and a half, plus build a massive load-leveling system. HUGH HIXON, PHOENIX, ARIZ ARIZ Arizona (old style) . Research into the storage of solar power during off hours is necessary now, but when the solar-power grid is sufficiently large In mathematics, the phrase sufficiently large is used in contexts such as:
WILLIAM NEWMAN William Newman may refer to:
Articles on solar cells always avoid discussing what I consider to be two crucial points. First, solar cells have a limited service life. Second, it takes a lot of energy to make a solar cell in the first place. So, you have to ask, can you get enough energy from a solar cell over its useful life to make another solar cell? TOM SARGENT, TUCSON, ARIZ. Researcher Nathan Lewis says, "More energy from the sun hits the Earth in 1 hour than all the energy consumed by humans in an entire year." So what? If it's theoretical limits we're talking about, there's over 20,000 years' worth of uranium in the oceans. STEVE BRIGGS, CHAMPAIGN, ILL. Aren't they called leaves? Instead of reinventing the tree with "organic solar cells," why not do research on harvesting electricity directly from trees? CLARENCE GUIDRY, NEW ORLEANS New Orleans (ôr`lēənz –lənz, ôrlēnz`), city (2006 pop. 187,525), coextensive with Orleans parish, SE La., between the Mississippi River and Lake Pontchartrain, 107 mi (172 km) by water from the river mouth; founded , LA. This story and "Spinning into Control" (SN: 5/19/07, p. 312) should be combined. A flywheel-energy-storage device under a building roofed with solar cells is the ideal solution. BOB KOSTER, NORTH TUSTIN, CALIF. |
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is true for sufficiently large
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