Thursday, March 10, 2011

Solar Revival

Been some three decades, just think where we'd all be if it wasn't brought down but allowed to flourish in the once American way, that to left some three decades ago!!

With falling costs, improved efficiency, and fresh designs, the old stalwart photovoltaics are again poised to ascend

Photovoltaic panels will generate about 30 percent of the power needed at the NASA Sustainability Base in Moffett Field, California. Image: William McDonough + Partners

February 2011 - Photovoltaics, the conversion of solar radiation into electricity, reached two important milestones in 2010. First, new installations of photovoltaic (PV) modules were expected to surpass 14 gigawatts worldwide by year’s end—at least doubling the 2009 installations. That’s the equivalent of about 14 coal-fired plants. Also, for the first time anywhere, PVs crossed the “nuclear threshold”: energy from photovoltaics is now more cost effective for North Carolina consumers than nuclear energy, according to a Duke University study.
Photons into Electrons

A basic PV module consists of two semiconductor layers. As light energy strikes the first layer, electrons are “excited” and are captured in the second layer. The amount of energy captured is limited to a small bandwidth of the sun’s available energy. Current commercial solar cells range from 7 to 24 percent in efficiency, but given the quantity of solar radiation available, this percentage can amount to significant power. {continued}

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