How Solar Power Could Become Cheaper Than Coal | Alternative Energy | DISCOVER Magazine

How Solar Power Could Become Cheaper Than Coal | Alternative Energy | DISCOVER Magazine: "The limitations of current-generation solar cells are painfully clear. Although experimental cells have reached efficiencies greater than 40 percent, most silicon-based commercial designs struggle to get past about 20 percent. The lower the efficiency, the more cells it takes to generate a given amount of electricity. That in turn makes photovoltaics bulky and expensive. As a result, the United States had just 800 megawatts of grid-connected solar photovoltaic power in 2008, and solar accounted for less than a tenth of one percent of all energy consumed in the country."