In another energy first, Gill is the brainchild of the advanced energy recovery system (AERS) implemented at Gills Onions in 2009. The system converts the unusable portion of the fresh-cut onion into renewable energy and cattle feed. The process reduces greenhouse gas emissions and saves electricity.

“We have an ambitious goal to achieve zero waste at our processing facility,” Gill said.

“With the AERS project, we now divert 100 percent of the onion waste which has helped us work towards reaching the goal. As of Jan. 1 of this year, we reached an overall diversion rate of 99.6 percent at the processing level,” said Gill.

The AERS system extracts juice from the onion peels which is then treated in a high-rate anaerobic reactor with bacteria. The process produces methane-rich biogas which can power two, 300-kilowatt fuel cells which is 100 percent of the base load of electricity.

This is equivalent to powering 460 homes annually.

Gill estimates the annual electricity savings from AERS at about $700,000 annually, or about 30 percent of the plant’s electricity costs.

Previously, onion waste was hauled back to the farm and incorporated into soil; an expensive process involving labor, farm equipment, and fuel.

Another energy-saving project at Gills is the purchase of lighter trucks which allow the trucks to carry a 6,000-pound larger payload. This eliminates 500 truckloads annually at a cost savings per load of about $1,000. Due to the efficiency, the truck fleet was reduced from 19 to 16 trucks. The total annual savings generated by the truck savings is about $500,000.

Another method of energy efficiency is the move to all diesel fueled equipment. Farm tractors and trucks already use diesel, but forklifts at the onion processing facility are propane powered. The company plans to install an on-premise diesel fueling station. All equipment will be diesel powered.

Water conservation is another effort underway at Gills. The company has undertaken a water study through a grant from the California Energy Commission to study ways to recycle water from its wastewater treatment plant for use in cooling towers, bin washes, and anaerobic digestion processes.

In another water-savings move, Gills Onions switched from conventional irrigation methods in onion production to surface drip. The change reduced water consumption by about one-acre-foot per acre.

cblake@farmpress.com