Waste to Energy
Waste to Energy

Gills Onions’ award-winning Waste-to-Energy project, the Advanced Energy Recovery System (AERS), has allowed us to become the first food processing facility in the world to produce ultra-clean energy from our own waste – converting 100% of our daily onion waste (up to 300,000 lbs) into renewable energy and cattle feed, reducing greenhouse gas (GHG) emissions, and saving us in annual electricity costs.

Everyone knows the power of onions: just one can reduce a person to tears. But now, we celebrate the power of onions in a new way that sets a precedent for food processors of all kinds to transform food waste into valuable, renewable energy. We engaged four important project participants - HDR Engineering, Inc., Deaton & Associates, LLC, Calkins Electric, Inc., and Hartigan/Foley to design, coordinate and construct a system to enhance our sustainable practices while reducing our environmental footprint.

The Advanced Energy Recovery System (AERS) that went into operation in July 2009 converts all of our daily onion waste into a combination of renewable energy and cattle feed. The AERS eliminates the formerly labor intensive and expensive process of hauling onion waste to farm fields, where it was worked into the soil. Environmental benefits extend to the local community, the state of California and beyond, with profound implications for agricultural food processors around the globe.

The new system extracts the juice from the onion peels and treats it in a high-rate anaerobic reactor to produce methane-rich biogas that powers two 300-kilowatt fuel cells. The resulting electricity is used to power the onion processing plant, saving an estimated $700,000 annually in electrical costs. The onion pulp that remains after the juice is extracted is processed into cattle feed cake that is sold to local cattle ranchers.

Additional savings come from the elimination of $400,000 in annual costs associated with hauling onion waste to farm fields. Greenhouse gas emissions are reduced through the elimination of hundreds of truck trips on California roadways that moved this waste stream each year. The result is increased energy independence, elimination of a significant waste stream, reduced operational costs and a smaller carbon footprint, with an estimated reduction of 14,500 metric tons of CO2e (equivalent) emissions per year.

The combination of the energy produced, cost savings generated and grant funding for renewable energy projects will result in a full payback of the $10.8 million total system cost in less than six years.

Stationary Fuel Cell Installations in California