Energy, layer by layer
Spending $9.5 million is enough to make most business owners cry, but for Steve Gill, co-owner of Gills Onions, it meant the fulfillment of a longtime goal.
Gills processes as many as a million pounds of onions a day at its Oxnard facility, which employs about 400 people and is the largest onion processor in the country. Its daily work generates about 300,000 pounds of onion waste, but a new energy recovery system at Gills turns what was once thrown away into clean heat and electricity and valuable cattle feed. The system generates 600 kilowatts of electricity.
“It’s a hard pill to swallow, but it’s been one my goals for my whole life to take care of this waste,” Gill told the Business Times.
Gill’s investment will pay for itself in about six years. The plant has been online for a few weeks, and once he proves it works, he’ll get a $2.7 million check from the Southern California Gas Co., which is administering money from a state program designed to encourage big users to generate their own energy.
Before the new fuel-cell plant, Gills put its waste out onto fields, where it generated carbon dioxide and methane as it decomposed. The process also cost a lot of money in diesel fuel to transport the waste, tipping fees to dump it and labor to spread it. Turning the waste into energy instead will save the company $700,000 in electricity costs, $400,000 in land-application costs and reduce its greenhouse gas emissions by up to 30,000 tons annually.
Here’s how the plant works. To get the good part of the onion, Gills sheds the tops, bottoms and peels. That waste goes into a giant screw press that separates the juice from the solids. From there, the solids are sold off as cattle feed. The juice then goes into a digester, where microorganisms turn it into methane and carbon dioxide.
“You can kind of think of it as a big stomach,” said David Carrell, a senior account executive with the Southern California Gas Co.
From there, the methane goes into a fuel cell that combines it with oxygen to produce water and electricity. But getting the gas to work in the fuel cell proved a challenge because of hydrogen sulfide and other gases produced by the onion juice that would damage the fuel cells.
Carrell helped Gills apply for a $500,000 grant to fund research by the Gas Technology Institute to solve the problem.
“Gas from onions had never been done before,” Carrell said. “You can’t send high-sulfur gas to the fuel cells. It took some special filtering to get the sulfur out.”
Gill said the company had to pioneer many of the technologies and techniques involved in turning onion waste into energy. It simply hadn’t been done before.
“There are not a lot of bioreactors in the U.S., and there are not a lot of people who know how to use them the way we wanted to use them,” Gill said. “We had to do all the research and development — and go down all the dead-end roads — ourselves.”
The search for a method started several years ago, Gill said. At first, the idea was to use the onion waste in solid form, but it would have taken weeks for microorganisms to break it down into gases.
Gill had the idea to press the waste, sell the solids as feed and use the juice for energy. He said the microorganisms can go through a batch of thousands of gallons of juice in about two hours. The firm worked with researchers at the University of California, Davis, to perfect the process.
“Our pilot was a one-liter plant in a UC Davis laboratory,” Gill said. “We jumped from that to our 145,000 gallon plant.”
Gill said the bacteria used in the process came from a beer factory that used them to process waste. “These poor bacteria,” Gill said. “These beer-guzzling bacteria came from a plant in Texas and got shocked with onion juice.”
Gill’s engineers are still perfecting acidity levels and other minor details. But the entire ordeal may lead to a new business – Gill said he has heard interest from a carrot processor about implementing a similar system.
“It could become a new venture for us to help other companies analyze and deal with their waste,” Gill said. “We’ve done all this research and don’t want it to stop at this one project.”
Gills Onions is in the midst of a host of other green-minded activities. It recently signed on with the California Climate Action Registry and is gathering information for a baseline measure of its greenhouse gas emissions.
Once that baseline is complete, the public will be able to view it along with improvements the company makes. Oxnard-based Agromin is a member of the group, as are the cities of Thousand Oaks, Ventura and Santa Barbara. Gills is also working with the Bren School of Environmental Science and Management at the University of California, Santa Barbara. Four graduate students there are working with the firm on drawing up a plan to make Gills Onions a zero-waste company.
Though sustainable business practices have recently spilled into the mainstream, Gill said they’ve been on his mind since he started the company more than 20 years ago.
“We’re working on it all the time,” Gill said. “We use the land over and over again to produce crops, so we have to take care of our natural resources to stay profitable and stay in business.”
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