PG&E starts getting gas from manure

The utility and a company called BioEnergy are ready to use bovine biomass from a Fresno area farm to help heat homes across California.

Tech Culture

The renewable energy industry hits the fan Tuesday in California.

Pacific Gas & Electric and BioEnergy Solutions plans to open a pipeline Tuesday that will deliver methane to the utility from a manure-to-gas facility at a Fresno-area farm. Some farms in California, such as cheese maker Joseph Gallo Farms, and a number in Europe already generate gas from manure, but they also consume it to run their operations. This marks the first time that manure-generated gas will get sold across pipelines in the state.


BioEnergy Solutions owns and operates the digester (the thing that converts the manure into gas), which is located on the 5,000-cow farm, called Vintage Dairy. The company says it will soon build digesters at other nearby farms. The Vintage Dairy facility is expected to provide enough gas for 1,200 homes. Ultimately, BioEnergy will deliver 3 billion cubic feet of gas to PG&E a year, enough gas for 50,000 homes.

Although BioEnergy and PG&E talk about how many homes the gas could serve, the utility will actually use the gas to run electrical power plants. PG&E has set a goal of generating 20 percent of its , not including power from hydroelectric dams. Although the utility gets only a small amount of its power now from utilities, it has signed enough contracts to inch it past the 20 percent mark, said a spokeswoman.

A single cow is probably good for after the conversions are calculated, according to some estimates. Cows crank out about 120 pounds of manure a day. Just in case you were wondering.

PG&E wouldn't say what it is paying for the gas, but contends that the prices are competitive. Manure won't be the only source of renewable gas in the future. Other companies such as Ze-Gen and Onsite Power Systems are working on converting other types of trash into power.

BioEnergy uses the storage pond method for converting manure. In a nutshell, the manure is placed in a big pond with microbes, which break down the manure. The gas from the digester--which ordinarily would float into atmosphere and contribute to greenhouse gas levels--then goes to an upgrade facility that separates the methane from other gases conjured up by the manure. The digester will prevent approximately 1,500 tons of methane, one of the more harmful greenhouse gases, getting into the atmosphere from the Vintage farm alone.

The pond at the Vintage facility can hold around 37 million gallons of water and manure, which will no doubt make for great discussions on any Cub Scout field trip. Other companies, such as Microgy, have turned to thermophilic digesters, which use a combination of heat and microbes.

The gas from BioEnergy's Vintage digester will be piped to the nearby upgrade facility, which then connects to commercial natural gas pipelines. Other farms will also pipe gas to the facility.

Besides serving as a source for natural gas, these digesters serve other environmental functions. Manure storage facilities are a source of groundwater pollution as well as greenhouse gases, so the more that's digested, the better.

Normally, getting rid of manure is a regulatory and financial headache for farmers. With digesters, however, they typically no longer have to pay disposal fees, or can even get a small fee from the operator of the digester, depending on the contract.

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