LOS ANGELES: Onions make you cry, add flavour to food and are touted for their medicinal benefits. Now the vegetable has another use – powering up green energy.
A new system is up and running at Gills Onions, the largest fresh onion processor in the United States, converting onion juice into electricity.
The Oxnard, California-based company expects its new onion-fuelled power to reduce its electric bill by US$700,000 (RM2.5 million) a year and cut its annual greenhouse gas emissions by up to 30,000 tonnes.
The happy ending to this green energy tale, however, started with another question: how to get rid of onion
waste.
“When we peel an onion, 35 to 40 per cent of the onion comes off before we have a usable onion. That’s the top, tail and skin around the onion before you get to the meat,” said Steven Gill, co-owner of the 25-year-old company.
They used to haul the waste to the fields for composting, but that became a problem. Ten years ago, Gill started looking at technology for a solution, including microturbines.
“We ended up shredding the skins as they come out of the plant and extracting all the juice, which is very high in sugars, and bacteria love that stuff,” Gill said.
In the new system, bacteria produce methane gas from the juice. The gas then goes to two 300 kilowatt fuel cells, creating enough power for 460 houses. The company expects to get 35 to 40 per cent of its electricity
from the on-site generator.
The company invested US$9.5 million in the project and will receive US$2.7 million from Southern California Gas Co, a regulated subsidiary of Sempra Energy, as part of a State programme to encourage self-contained generation by businesses. In addition to cutting its electric bill, the company will save US$400,000 in hauling costs and expects payback in six years.
The onion grower now has new goal: to be a zero-waste facility by 2011.
“We want to follow it all the way through and make the full circle,” Gill said.
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