"Cow Power" is generated by using a methane digester to turn manure into biogas. Environmentalists say California is being surpassed by other states when it comes to using biogas...

"...Texas, Wisconsin. But California, which is the biggest dairy state in the country, we haven't been able to make it work here."

Stacey Sullivan is with the group Sustainable Conservation. He says California biogas generators haven't had the same government policy benefits and subsidies as say a solar developer…

"…who's achieved a certain level of cost-efficiency based, at least in some part, on these government programs, is going to be able to come in at a lower price than a bio-energy developer who hasn't had that benefit."

…prices paid for by utility companies.

Renewable energy advocates are urging the California Public Utilities Commission to set up a pricing mechanism that puts biogas at rates competitive with solar and wind.

The PUC is expected to make a decision next month.