Who doesn't love an onion power story?
Until today, Gills Onions, a southern Californian farming giant that boasts "the largest fresh onion processing plant in the world," produced about 300,000 pounds of "onion waste" a day.
But no longer. On Friday the company unveiled a clever scheme to convert onion byproducts into electricity.
One of the main components of the system is an anaerobic digester that converts treated onion plant waste into biogas. That gas is then conditioned and turned into methane, the main component of natural gas. Then the natural gas is fed into a 600-kilowatt fuel cell from Fuel Cell Energy to make electricity.
Gills Onions estimates that the $9.5 million project will have a six-year investment pay back. Among the financial benefits are reducing its electricity bill by $700,000 a year and $400,000 annual savings from handling onion wastes, which used to be spread on their land. The project also received $499,000 from a state waste-to-energy research program
All this would seem to be enough to make a waste-not/want-not enthusiast cry onion-induced tears of joy.
But what I always wonder with these "farm-waste-to-gas" stories is why we would be considering left-over vegetable matter "waste" to begin with. There's no vegetable waste in my kitchen -- it all goes into the compost bin and ends up refreshing my garden. I would presume that a farm as big as Gills could recycle plant waste back into the land, as well.
Whenever we turn plant products into power, we're removing nutrients from the ecosystem -- forever. How sustainable is that, in the long run?