Campbell Soup Co. may be based in Camden, but Napoleon, Ohio, is the site of the company's biggest food-manufacturing plant.

Located near Toledo, the factory employs about 1,500 people who produce soups, sauces and beverages for the consumer-products giant.

It's also one of the focal points for Campbell Soup's efforts to make its operations more sustainable. In December, the company switched on a 9.8-megawatt solar-panel farm that is expected to supply up to 15 percent of Napoleon's electricity needs.

Of course, the sun doesn't shine every day, but name a manufacturer that goes a day without producing waste. That's why Campbell Soup has committed to directing organic waste from its food-processing operations in Napoleon to a commercial biogas power plant now under construction nearby.

Campbell's plans to divert between 35 percent and 50 percent of its waste from landfills to a $10 million anaerobic digester and electric generator being developed by CH4 Biogas L.L.C. Methane gas produced in the digester — a large airtight tank — would fuel turbines that the food company hopes will generate enough electricity to replace up to 25 percent of the conventional power it now purchases.

Campbell Soup signed an agreement to buy all the electricity generated at the CH4 Biogas plant for the next 15 years at a flat cost. The company did not disclose what it would pay for that electricity once the plant comes online in mid-2013.

Lauren Toretta, CH4 Biogas' vice president, said the Ohio project would be the four-year-old company's second in the United States. The first is a pilot plant on a dairy farm in Covington, N.Y., about 50 miles south of Rochester, that began operation in December.

CH4 Biogas has the exclusive right to use biogas-based renewable-energy technology developed by Bigadan A/S, a privately held Danish company that is behind about 40 such projects globally. Financing will also come from Europe, via the Danish state export credit agency, Eksport Kredit Fonden.