THE DALLES, Ore., Jan. 21 (UPI) -- Faced with rising energy costs and growing demand, much of U.S. industry and government are turning to renewable energy as a solution, but for many citizens it's unclear when and how well these technologies will work.

Given the approximately $2 billion allotted to renewable energy research and development in the recently signed Energy Independence and Security Act of 2007, taxpayers may want to know what their money is going to support.

Many renewable energy technologies exist, and though different entities classify different technologies as renewable, most lists include wind, solar, geothermal, hydropower, fuel cells and biomass. In 2006 renewable resources provided 7 percent of the nation's electricity supply, according to the Energy Information Administration, the statistical agency for the U.S. Department of Energy.

Many of these technologies have been progressing in recent years and hold high potential to decrease U.S. consumption of fossil fuels, as well as benefit the environment because of low, or nonexistent, carbon dioxide emissions, said Gary Schmitz, spokesman for the National Renewable Energy Laboratory, directed by the Department of Energy.

"In terms of potential, (renewable energy) is virtually limitless," Schmitz told United Press International. "Theoretically, if you took today's solar photovoltaic technology and employed it in a square of the Arizona desert, 100 miles on a side, you could provide the entire country with its electricity needs."