Onion power could now mean more than daunting breath. The nation's largest onion producer is covering new ground with renewable power and tackling the energy demands of food production.

Gills Onions is now home to an anaerobic digester and efficient fuel cells. Originally used as compost, the onion waste is now used as feedstock to produce electricity.

Anaerobic digesters work by methane recovery, converting material (onion juice in this case) into methane, which can then power the fuel cells.

Onion waste has never been used in this way before, and was studied extensively at the University of California-Davis. During the two years of study, the researchers determined that onion juice was superior to the skin, due to its high sugar content, for energy production.

The onion producers worked with Biothane, a Netherlands-based company (with offices in New Jersey) that designed an anaerobic digester specifically for onion juice. The Gills chose two 300-kilowatt units from FuelCell Energy for their energy storage needs— the project has enabled the company to receive a $2.7 million federal grant and $3,000 per kW in tax credits.

FuelCell Energy is also working with a number of facilities to address power needs; including the Santa Rita Jail and the Sierra Nevada Brewing Company.

Dealing with the onion waste on site will also keep transportation costs down as well as energy demand. The resulting waste, once the juice is separated, is used as cattle feed.

The project will save $700,000 in annual electricity costs, paying for itself in less than six years. With projects like this sprouting up throughout the U.S., stationary fuel cells seem a strong short-term possibility for green power.