LODI, CA - It might be easy to look around and think you know exactly what goes on at the Castelanelli Brothers Dairy. Cows eat, drink, make milk. End of story.
Think again.
"One cow will produce enough energy to keep a 100-watt light bulb burning 24 hours a day," said Larry Castelanelli. He doesn't have one cow. He has 3,000. That's a lot of milk, and a lot of something else.
Larry has harnessed the power of his cows' poop. "What's bubbled up here is all that methane gas," he said, standing on top of a large bubble encasing a lagoon of methane. Yes, he can literally stand on the methane gas produced his cows.
The process begins as you might expect, when the manure hits the floor. Twice a day, every ounce of cow waste is flushed away and the solids are removed from the water through a separation machine.
"All it is is a screen," said Castelanelli. "It takes the solids out, the solids drop down here, and the water goes over to the digester."
The digester is a two-acre lagoon covered by a bubble, where the methane from cow waste is harnessed and transferred to a generator. "We take this gas that would normally go up and get into the ozone. Then we capture it, run it through the generator and we get electricity. We run the dairy with it." And Castelanelli never has to worry about running out of energy. "Solar and wind is great," he said. "But if the wind's not blowing or the sun's not shining … here with gas, it's 24 hours a day."
Even though Castelanelli doesn't need PGamp;E much these days, he still pays a regular monthly bill just in case his generator goes down.