Garbage-to-gas system makes its debut

The University of California at Davis on Tuesday formally unveiled a digester that converts food scraps and other garbage into natural gas and methane. The gases can then be converted to electricity. The system, developed by the university and Onsite Power Systems, is essentially a sealed network of tubes and chambers where bacteria consume leftovers and then excrete gases. It can convert about eight tons of garbage a week and will eventually process eight tons a day, the university said. A ton of garbage provides enough electricity to power 10 average California homes for a day.

Several companies are trying to figure out ways to exploit waste products as an energy source. In their favor, they produce natural gas, which releases fewer pollutants than coal or car gas. And the fuel stock--old fish heads, chewed-up pieces of meat, soggy Lucky Charms--costs little to obtain. In Texas, Microgy is opening up a series of thermophilic digesters that will transform cow manure into natural gas. So much gas can be produced that Microgy will be able to ship it over commercial natural-gas lines. Agribusiness giant Cargill announced on Tuesday that it will help Environmental Power, which owns Microgy, to promote its technology.