Largest Manure-to-Methane Plant Begins Operation

Largest Manure-to-Methane Plant Begins Operation

Huckabay Ridge, a manure-to-natural gas facility, opened for business Monday in what will be the first of many similar projects for New Hampshire-based Environmental Power Corp. and its subsidiary Microgy Inc.

Billed as the country's largest methane-to-gas plant, Huckabay Ridge generates the renewable energy each day from some 200 tons of manure it takes off the hands of local dairy farmers that have in recent years come under attack for manure runoff.

The $18.5 million plant entered into a contract last month with Pacific Gas and Electric Co. to begin selling the utility natural gas next fall. The contract is part of the utility's efforts to increase renewable energy to 20 percent of its portfolio by 2020 as mandated by California law.

The facility can generate enough natural gas to power 11,000 homes annually.

Erath County, where the plant is located, is home to 52,000 dairy cows. Local dairy farmers can dump their manure at the plant for free, but pay for transport. That's a good deal for an industry that has faced previous litigation over manure runoff in nearby Bosque River, which feeds into Lake Waco, Stephenville's main water source. Dairy cows produce more about 140 pounds of manure each day.

The manure is mixed with water and restaurant grease before going into digester tanks where the bacteria generates the methane gas during feeding. The gas is purified before distribution through a pipeline. The Texas Department of Transportation reportedly buys the residue byproduct as compost. The company plans similar projects in California and Texas.

A greenhouse gas, methane remains in the atmosphere for up to 15 years and is more than 20 times more effective than carbon dioxide in trapping heat in the atmosphere, according to the U.S. Environmental Protection Agency.