Some renewable energy experts see a future where decomposing garbage takes on new life and plants are grown as power.

   California's energy deregulation removed requirements for minimal energy production of energy from renewable sources. As a result, the state lost about 400 megawatts of biomass-produced electricity, said Kevin Craig, technology manager of the biopower program at the Department of Energy's National Research and Engineering Lab in Golden, Colorado.

   "Some of these plants could conceivably come back online" to help with the current power shortage, he said.

   Biomass generally includes any organic material, such as sawdust, tree trimmings and rice straw; poultry litter or other animal wastes; industrial organic wastes, such as paper pulp; municipal waste, including sewage; landfill gasses produced as bacteria break down trash; and waste from farms and orchards.

   Biomass can be burned as-is for energy; or be first processed into a liquid or gas for burning; or be made into chemicals, such as ethanol, that can be added to or replace gasoline.

   Ethanol, the most widely used biofuel, is added to about 9 percent of the nation's gasoline to reduce air pollution.

   Biomass in general provides about 25 percent of the world's energy needs, said Donald Klass, director of research at Entech International, Inc., a consulting firm based in Barrington, Ill. He is also president of the Biomass Energy Research Association, headquartered in the District of Columbia.

   In the United States, about 350 biomass power plants, many associated with commercial processes, generate 7.5 gigawatts of power. That's enough to meet the energy needs of several million homes.

   Biomass power is most common in industries such as paper mills, where the waste is a good source of fuel. Tapping otherwise unused resources — such as fruit pits, commonly burned for disposal — could present real benefits, said Verinder Singh of the Renewable Energy Policy Project, an advocacy group in Washington.

   Last November, the California Energy Commission and the Environmental Protection Agency formed a task force with a goal of doubling electricity production at landfills within five years. Currently, landfills have to collect and dispose of the explosive, foul-smelling natural gas generated there because it contributes to both smog and global warming.

   "The fuel is right there ... and its use is fairly free of environmental controversy," Singh said.

   "Only about 5 to 10 percent of the (gas) at larger landfills is used for power," said Don Augenstein, a research engineer at the Institute for Environmental Management in Palo Alto, Calif. "If you could make it all into electricity you might be able to power 3 percent of the United States, including homes and industry."

   On other fronts, researchers at Department of Energy-funded labs are working to develop bacteria that can convert corn or other plant material into ethanol at prices competitive with gasoline over the next decade.

   Added to coal-fired power plants, wood and other forms of biomass reduce pollution while only incrementally increasing costs, said NREL's Craig. The lab is currently studying projects using wood pellets, biomass gas, and a gasification process to make power, he said.

   Ultimately Singh sees the production of co-firing — adding enough biomass to current coal-powered plants to provide 5 to 10 percent of the energy, for example — as a move towards creating a biomass supply industry. He envisions farmers growing products specifically to be burned for electricity.

   "I think there's an enormous potential for electricity production from biomass," said Lewis Smith, an energy economist in San Juan, Puerto Rico. "However, the economics of biomass use are very site-specific. There are lots of feasible projects — and lots of projects that aren't."

   Biomass plants must be built near their fuel supply, since such material can be expensive to transport — and using gasoline-powered vehicles to move it would reduce expected environmental benefits. Biomass facilities will also need to be located near existing electricity transmission lines for the plant to be cost effective.

   Thus, the cost of energy produced from biomass varies greatly from site to site. Using biomass is expected to have a variety of enviornmental benefits. For one thing, burning biomass for power reduces emission of sulfur, a key component of acid rain, compared to fossil fuels, said Klass.

   Burning wood or other plant material does produce carbon dioxide — one of the chemicals widely believed to play a role in global warming. But proponents of biomass as energy note that the plant removed the same amount of carbon dioxide from the air as it was growing.

   In contrast, burning fossil fuels releases carbon dioxide that was trapped underground millions of years ago. Thus burning fossil fuels, unlike burning biomass, results in a net gain of carbon dioxide in the atmosphere.

   Beyond environmental goals, biomass joins other renewable energy sources in reducing U.S. dependence on imported energy sources. Biomass is also significantly less likely to be depleted than conventional energy sources like oil.

   These benefits, and the attention brought to renewables because of California's power shortage and the possibility of more widespread energy shortages this summer, translate into "an incredible opportunity to put a bunch of renewables online," said George Darr of the Bonneville Power Administration in Portland, Oregon.