Dairy farmers in Massachusetts are using food waste to create electricity. They feed waste into anaerobic digesters, built and operated by Vanguard Renewables, which capture the methane emissions and make renewable energy.
…The machine will grind up all kinds of food waste — “everything from bones, we put whole fish in here, to vegetables to dry items like rice or grains,” Franczyk says as the grinder is loaded. It also takes frying fats and greases.
…While Whole Foods donates a lot of surplus food to food banks, there’s a lot waste left over. Much of it is generated from prepping prepared foods. Just as when you cook in your own kitchen, there are lots of bits that remain, such as onion or carrot peel, rinds, stalks or meat scraps.
…In the digester, he combines all of this waste with manure from his cows. The mixture cooks at about 105 degrees Fahrenheit. As the methane is released, it rises to the top of a large red tank with a black bubble-shaped dome.
“We capture the gas in that bubble. Then we suck it into a big motor,” Melnik explains. Unlike other engines that run on diesel or gasoline, this engine runs on methane.
“This turns a big generator, which is creating one megawatt of electricity” continuously, Melnik says — enough to power more than just his farm. “We only use about 10 percent of what we make, and the rest is fed onto the [electricity] grid,” Melnik explains. It’s enough to power about 1,500 homes.
He says times are tough for dairy farmers, so this gives him a new stream of revenue. Vanguard pays him rental fees for having the anaerobic digester on his farm. In addition, he’s able to use the liquids left over from the process as fertilizer on his fields.