Both inventors and investors are betting that flexible sheets of tiny solar cells used to harness the sun's strength will ultimately provide a cheaper, more efficient source of energy than the current smorgasbord of alternative and fossil fuels. Nanosys and Nanosolar in Palo Alto -- along with Konarka in Lowell, Mass. -- say their research will result in thin rolls of highly efficient light-collecting plastics spread across rooftops or built into building materials. These rolls, the companies say, will be able to provide energy for prices as low as the electricity currently provided by utilities, which averages $1 per watt. The companies also say that the printed rolls of solar cells would be lighter, more resilient and flexible than silicon photovoltaics. Solar energy could furnish much of the nation's electricity if available residential and commercial rooftops were fully utilized. According to the Energy Foundation, using available rooftop space could provide 710,000 megawatts across the United States, whose current electrical capacity is 950,000 megawatts. Atluru of Draper Fisher Jurvetson [explains] Our view is that government can cause big problems, and it is the entrepreneurs who will make the big changes." Current cost of solar energy, per watt: $4-$5. Average cost of energy from traditional fossil fuel sources, per watt: $1. Estimated cost of energy from nanotech solar panels, per watt: $2. Total energy-generating capacity of the United States: 950,000 megawatts. Potential total rooftop solar energy capacity in the United States: 710, 000 megawatts.

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