Abstract

Only a small fraction of U.S. electricity needs are supplied by renewable energy technologies other than hydropower, because of their relatively high cost and the economics of the electric utility industry, which is faced with an increasingly competitive environment and is generally awash in surplus power. Despite the formidable technical hurdles that these technologies have overcome to bring costs down and increase reliability, further inroads have been thwarted by the lower cost of natural gas and the efficiency of gas-fired generating plants.

As costs continue to decline, however, the renewable energy market can be expected to grow, particularly if possible global warming trends continue to be linked with greenhouse gases, such as those emitted by fossil fuels. Other factors that are increasing interest in renewable energy include niche cost advantages, regulatory pressures, customer service requirements, fuel flexibility, and security.

The extent to which each technology is poised to advance is described in progress reports on photovoltaics, solar-thermal power, and wind, biomass, waste-to-energy, geothermal, hydropower, and wave energy.