Forget Tears, Onions Produce Electricity

While perusing the Web trying to figure out if all varieties of onions cause people to tear up, I stumbled across a news blurb that made me proud I knew what an anaerobic digester was and why it was used.

According to the news snippet, Oxnard, Calif-based Gills Onions produces up to 300,000 pounds of peels a day. Rather than waste them, the company uses the refuse to run its processing facility. Engineers installed machinery at the plant to grind and press the peels into 30,000 gallons of onion juice, which is fed into an anaerobic digester.

Wanting to learn more, I went to the company's website and found out that the biogas is cleaned and conditioned for use in two 300-killowatt fuel cells to produce combined heat and power for the facility's use. After solving the variable gas flow challenges, 112,000 standard cubic feet of piped-in natural gas per day has been replaced by the biogas feeding the fuel cells.

The technology earned the company and The California Energy Commission the 2010 Green California Leadership Award. In the category of waste management, the two received accolades for the Commission-funded Advanced Energy Recovery System (AERS) project implemented at the Gills Onions facility in Oxnard.

"Research and demonstration partnerships such as this yield results. In less than two years, we have implemented a project that solves a host of problems," says Energy Commission Vice Chairman Jim Boyd. "This award recognizes the elimination of up to 14,500 tons of carbon dioxide equivalent emissions per year, the saving of 40,000 gallons of diesel fuel per year used to haul onion waste, and the saving of almost 112,000 standard cubic feet of natural gas."

The things you learn when trying to figure out one of life's little mysteries. In case you're wondering, it appears that all varieties of onions have the capacity to make you cry. When you start to chop an onion, enzymes that were kept separate now are free to mix with sulfenic acids to produce propanethiol S-oxide, a volatile sulfur compound. Once the fumes hit your eyes, they start to tear up in hopes of purging the noxious fumes away.

Traci Purdum
Senior Digital Editor