Largest U.S. onion processor unveils biogas plant

Oxnard, Calif.-based Gills Onions is set to receive a $2.7 million award from Southern California Gas later this week for its system that converts onion waste into electricity and cattle feed.

As the largest processor of fresh onions in the U.S., Gills generates 300,000 pounds of onion waste each day. The energy recovery system mechanically extracts juices from onion waste, which then ferments in an anaerobic digester.

The resulting biogas powers two 300-kilowatt fuel cells, which saves Gills $700,000 a year in energy costs. The power is equivalent to the demand of 460 homes and represents up to 30,000 tons of greenhouse gases per year, according to Southern California Gas.

The $2.7 million award comes from the state's Self-Generation Incentive Program, which says Gills' system is one of the largest installed since the program began in 2001.

Earlier this year in Northern California, Pacific Gas & Electric contracted with California Bioenergy for its greenhouse gas emission (GHG) reductions thanks to a system that processes the dairy farm’s manure through an anaerobic digester, trapping the methane gas produced as the manure decomposes. The renewable energy produced from the cow pies is planned to power the dairy’s onsite operations (see Holy cow! A pie-powered dairy farm?).