[USA Today] Solar power has long been the Mercedes-Benz of the renewable energy industry: sleek, quiet, low-maintenance. Yet like a Mercedes, solar energy is universally adored but prohibitively expensive for most people. A 4 kilowatt solar photovoltaic system costs about $34,000 without government rebates or tax breaks. As a result, solar power accounts for well under 1% of U.S. electricity generation. Other alternative energy sources, such as wind, biomass and geothermal, are far more widely deployed. The outlook for solar, though, is getting much brighter.