While many see restaurant leftovers as trash, a San Francisco-area utility sees them as a source of energy.

The East Bay Municipal Utility District, which provides water and wastewater treatment in the eastern San Francisco Bay Area, is turning food scraps from 2,300 Bay Area restaurants and grocery stores into electricity to help it power its wastewater facility.

Every day, one or two 20-ton trucks pull up to the plant here and dump food waste into giant tanks. At the end of the process, the food scraps create methane gas. It helps power the plant's electricity-making generators.

The project is the first of its kind in the nation for a wastewater treatment plant, the Environmental Protection Agency says, and it's at the forefront of an almost untapped renewable energy resource.

While a handful of utilities, companies and universities nationwide have attempted to recycle food scraps into energy, less than 3% of those scraps are diverted from landfills, the EPA says. Most often, food waste that doesn't go to landfills is composted for use in fertilizers. Every year, more than 30 million tons of food waste goes to landfills, the EPA says, accounting for about 20% of landfill waste.

The San Francisco-area utility district powers its wastewater plant, which serves about 650,000 Bay Area homes, by capturing methane gas by processing many kinds of waste, starting with wastewater. To take up excess capacity, the utility started collecting other waste in 2001, including that from wineries, dairies and chicken processors, says David Williams, director of wastewater for the utility.