The nation’s largest manure-to-natural gas plant got up and running Monday in the heart of Texas dairy country, a project expected to produce enough energy to power 11,000 homes a year.

In a high-profile example of the growing need for alternative energy, Huckabay Ridge gets manure from local dairy farms, processes it with grease and other restaurant waste, purifies it and turns it into natural gas.

“The beauty is that you take the waste products and you create a useful form of energy,” said Richard Kessel, president and CEO of Portsmouth, N.H.-based Environmental Power Corp. Its wholly owned subsidiary, Microgy Inc., owns the facility. “We look at these as non-depleting gas wells with a long-term supply of renewable energy.”

The Lower Colorado River Authority buys the gas and uses it to power homes in Central Texas, officials said. Next fall, San Francisco-based Pacific Gas & Electric Co. will buy natural gas from Huckabay Ridge, which will generate the energy equivalent of 4.6 million gallons of oil annually.

“This is a turning point in agriculture. … Agriculture is no longer just food and fiber; it is now food and fiber and fuel,” state Rep. Sid Miller, R-Stephenville, said Monday at the plant’s opening ceremony, where only a faint odor of manure wafted through the air. “Agriculture is going to responsible for producing a large percent of the world’s fuel.”

Huckabay Ridge is near Stephenville in rural Erath County, the state’s top-producing dairy county. The state has about 335,000 dairy cows, including 52,000 in Erath County. Each dairy cow produces more than 15 gallons of manure per day.

The site had been a composting facility where farmers took manure. Now, more than a dozen farmers take their herds’ waste there, paying only for transportation. The facility does not buy the manure or charge farmers to drop it off.

“It’s a great thing for everybody,” said John Traweek, whose family-run Jam Dot Dairy has been operating in nearby Lingleville for 45 years.

He said it was a much-needed benefit for Erath County dairies, which have come under fire for manure runoff in the Bosque River. It is the main water source of Lake Waco downstream, where an overabundance of phosphorus caused massive algae blooms that were blamed for tainting Waco water’s taste and odor.

Last year Waco dropped its federal lawsuits against six of the 14 dairies it sued in 2004 in exchange for farmers’ changes designed to reduce water pollution. Waco previously reached settlements with eight dairies.

“I think the dairymen are excited about the opportunity this facility does provide, but this type of technology might not be the solution for every dairyman,” said John Cowan, executive director of the Texas Association of Dairymen.

Each day, about 10 manure-filled trucks arrive at the Huckabay Ridge, driving up a ramp made of dried, dark manure. The loads are dropped into a small tank where water is added, and then into a 1 million-gallon drum called a slurry tank, where the liquified waste swirls around.

The manure and restaurant grease then go into one of eight 900,000-gallon digester tanks, where bacteria feed on the waste for weeks to create methane gas. After purifying it to commercial standards, the natural gas is then distributed through a pipeline.

Officials said Texas has been a leader in agriculture and energy.

“Today these two sectors of our economy join together for something very special,” said Texas Agriculture Commissioner Todd Staples. “Today is a real winning solution for agriculture, for our environment, for our state’s economy and for new sources of energy.”

Environmental Power has started similar projects in California and a few other states. It also has three digesters on small family-owned Wisconsin dairy farms that produce enough electricity for about 1,800 homes.