A New Reason to Cry: Onions for Energy

As electric vehicles gain traction, a concern is how to produce renewable energy to charge them up. Well, look no further than your refrigerator. One company is using onions to produce electricity and the owner, Steve Gill along with brother David Gill of Gills Onions, are crying all the way to the bank. In the new energy paradigm, many experts predict that we will no longer transport our energy around the world but will create it within our own communities. Using the waste juice from onions fits right into this scenario.

Gills Onions is the largest fresh onion processing plant in the world. The company has more than 15,000 acres of farmland and 300,000 square feet of processing and warehousing facility. Gill was looking for ways to reduce his costs in his farming operation when he began to experiment using the juice from his onion crop in Oxnard, California to create the energy to run his lighting and refrigerators. The result was the creation of an Advanced Energy Recovery System (AERS).

Not only is this process working, but according to an article in the LA Times, he is saving $700,000 a year on his energy bills and $400,000 a year on disposal costs. Wowzers. Ironically as many look to creative ways to produce renewable energy to help the environment, Gill was looking for creative ways to save money –not to go green.

The government is impressed with his operation and he has received more than $3 million in government funding and power company incentives to continue. Gill estimates that the money he invested into the project, $9.5 million, will be returned within six years. His ROI will come even sooner if energy prices continue to rise.

The AERS systems not only saves money but eliminates 30,000 tons of CO2 from entering the atmosphere. This is roughly the equivalent of the emissions produced from 5,000 cars per year. In addition, the company produces enough extra energy to power 460 homes per year.

So how does it work? ‘In an onion peel’ the system converts methane from fermented onion juice into energy burned in two on-site fuel cells.

Okay, maybe its not quite that simple.

First, machines extract onion juice that is then sent to a 145,000-gallon holding tank kept at a temperature of 95 degrees. Once inside, bacteria (the same used to ferment beer) produce methane gas by feasting on the carbohydrates in the fermenting juice. Hmm…kinda like farting cows….

Next, the gas is purified, dehumidified, compressed, and burned in the fuel cells at temperatures that exceed 1,000 degrees. The 600-kilowatt system produces enough power and then some to operate the plant’s refrigeration units and lighting.

The Gills will eventually add a battery component to the system to store energy for use during peak times when electricy prices are higher.

While using methane may not be a silver bullet, it is a very viable way for communities to produce the energy they need to power their homes and eventually their cars.


Joanna Schroeder

Joanna is a writer and consultant specializing in renewable energy and sustainable agriculture issues.