San Antonio plans to convert human waste to energy

San Antonio residents produce about 140,000 tons a year of a substance gently referred to as "biosolids," which can be reprocessed into natural gas, said Steve Clouse, chief operating officer of the city's water system.

"You may call it something else," Clouse said, but for area utilities, the main byproduct of human waste - methane gas - will soon be converted into natural gas to burn in their power plants.

The city approved a deal where Massachusetts-based Ameresco Inc will convert the city's biosolids into natural gas, which could generate about 1.5 million cubic feet per day, he said.

Methane gas, which is a byproduct of human and organic waste, is a principal component of the natural gas used to fuel furnaces, power plants, and other combustion-based generators.