Invention Awards: A Generator That Runs on Kitchen Grease

The Vegawatt provides restaurants' power using their leftover cooking oil

Today’s featured Invention Award winner kills two birds with one stone: providing a simple and cheap alternative energy source while widening the market for delicious fried foods. Everybody wins!

The nondescript six-foot-tall box behind Finz restaurant in Dedham, Massachusetts, looks like a tool shed, but actually it’s a self-contained grease refinery and five-kilowatt generator. Engineer James Peret’s Vegawatt is the first all-in-one device that processes grease to continuously provide a building with electricity and hot water, heralding a significant change in alternative-fuel applications. “It’s a brilliant idea,” says Josh Tickell, author of Biodiesel America. “A waste stream to an energy source, with no intermediary.”

Last December, after a year of 80-hour weeks on the development, Peret, 33, installed the first Vegawatt at Finz, a joint that offers loads of fried seafood. With patents still pending, he’s reluctant to give specifics on its inner workings, but it begins with staff members pouring in 10 to 12 gallons of used deep-fryer oil each day. Before going into the Vegawatt’s generator, the bread-crumb-filled muck is deposited into a reservoir and undergoes a multi-stage cleaning, treatment and filtration process. At this stage, the oil is prepared for combustion with a method Peret devised that draws heat from the exhaust system. After that, the processed grease moves into a tank that feeds the modified 15-horsepower diesel generator. Heat from the Vegawatt’s engine coolant is used to warm the water in the building’s pipes, further reducing the restaurant’s energy needs.

The Vegawatt can process about 80 gallons of grease a week (standard for large restaurants) and produces five kilowatts of energy an hour, which could translate to monthly savings of $1,000, a 10 percent reduction in power costs. Peret is now selling the machine through his start-up, Owl Power Company, pitching it as the perfect way to go green, save money, and serve delicious fish and chips at the same time.

Invention: Vegawatt
Inventor: James Peret
Cost: $300,000
Time: 4 years
Is It Ready Yet? 1 2 3 4 5

Vegawatt: How It Works

Dirty grease passes through a series of tanks and filters that scrub, heat, and refine it into fuel that burns clean in a diesel generator

Check out the rest of PopSci’s 2009 Invention Award winners!