At the Whole Foods commissary in Boston, the canola oil won't just be for cooking -- it will soon be used to make electricity. The natural foods grocer plans to run the walk-in freezer and the overhead lights using the new power source, reports The Boston Globe. By next year, a generator that's powered by the used cooking oil will provide all the electricity needed for the commissary -- about 2 million kilowatt hours a year.

The used liquid already flows throughout most of the plant, where employees prepare food sold in the region's Whole Foods stores. It starts in a 275-gallon bin on the second floor, slides down a pipe, and gushes through a spigot in the "cold kitchen." Commissary chefs turn a tap to get oil for salad dressings and hummus, or for deep-frying in the "hot kitchen."

Each week, about 1,200 gallons of oil go into making the more than 240,000 pounds of prepared food items that customers will buy at 43 stores in Massachusetts, Maine, Connecticut, Rhode Island, New York and New Jersey.

The cooking-oil generator, which will hook into the plant's electricity distribution system and operate in tandem with National Grid's utility lines, is expected to save Whole Foods at least 20 percent of the commissary's energy and waste costs.

Erin O'Brien, a spokeswoman for ISO New England, which operates the regional power grid, said efforts like Whole Foods' help maintain grid reliability, slow the growth of demand for electricity, and lessen the volatility of prices. Since 2003, O'Brien added, the capacity from such efforts in New England has almost quintupled, from 400 megawatts to 1,900 megawatts. That's enough to power at least 1.4 million homes.

Whole Foods said its canola oil-powered generator, which is scheduled for installation in January by Lifecycle Renewables Inc., of Marblehead, is just the latest in its long-standing mission to become as eco-friendly as possible. For instance, a fuel cell powers a Whole Foods store in Connecticut, and the same technology will be used at a store scheduled to open next year in Dedham, Mass. Also, a wind turbine is expected to be installed at a Whole Foods seafood facility in Gloucester, Mass. Already, most of the company's stores keep about 80 percent of their waste from going to landfills.