San Francisco's PG&E (NYSE: PCG) wants to pump up its clean energy resources with a boost of biomethane.

The power utility said it's looking for partners on a project to demonstrate technologies that could cost-effectively produce significant quantities of the renewable natural gas.

PG&E said it's hoping to encourage the development of pre-commercial biomethanation systems. Biomethanation is the process of converting biomass to biomethane.

"The purpose of this request for information is really to understand the technologies for producing biomethane from additional sources of biomass," Jennifer Zerwer, spokeswoman for PG&E, told Cleantech.com.

The utility already gets some biomethane from Portsmouth, N.H.-based Microgy, a subsidiary of Environmental Power (Nasdaq: EPG), and Bakersfield, Calif.'s Bioenergy Solutions (see Waste to energy shows potential).

Take a look at Microgy's Huckabay Ridge plant in Texas >> 

That gas is captured from cow manure, but PG&E is looking for projects that go beyond cow pies and look at pipeline-quality gas derived from agricultural crops and wood wastes.

"Generally, those items have been burned for generating electricity on demand, and we would like to explore available technologies for turning them into gas," said Zerwer.

If PG&E picks a group to work with, it plans to sign agreements for a project in the second half of this year, and a demonstration facility could be operational as early as 2010.

The utility said California and the western region of the U.S. contain large quantities of biomass, which could go toward the state's renewable energy requirements while cutting the need for landfill disposal.

The power company plans to use its existing pipeline infrastructure to transport the biomethane, delivering it for high-value uses such as dispatchable power generation.

Dispatchable generation can be turned on or off at request, as opposed to base load generation, such as nuclear and coal, or intermittent sources, like wind and solar.

Any new biomethane would go toward PG&E's goal of having 20 percent of its power under contract or delivered by renewable sources by 2010.

The company currently gets 12 percent of its power from renewable energy, but it hasn't set any specific goals for this biomethane project.

"It's really too early. We're really trying to understand what are the technologies out there, what are the market needs for support," said Zerwer.

She said the end goal is for the project to demonstrate a variety of different systems.

Two companies that have already put their names down on a list of potential project partners for PG&E are Danville, Calif.-based Bio-Friendly Fuel Partners and Yountville, Calif.'s RealEnergy.

Bio-Friendly makes biodiesel from waste cooking oils, tallow, and vegetable oils. RealEnergy develops renewable onsite power plants for businesses.

PG&E has yet to set a budget in its guidelines for those potential partners.

"That's another part of this request for information that we're hoping to understand, what potential costs would be," said Zerwer.

PG&E's growing portfolio of renewable energy generation includes recent deals for solar thermal and wave power.

In November, the utility entered into a power purchase agreement with Palo Alto, Calif.-based Ausra for a 177 megawatt solar thermal plant to be built in central California (see PG&E, Ausra in 177MW solar thermal deal).

That project is expected to start generating power in 2010.

And just last month, PG&E signed the nation's first commercial power purchase agreement for wave energy with a deal for 2 MW of energy from Vancouver, British Columbia's Finavera Renewables (see PG&E to ride the waves with Finavera).

Finavera plans to deploy its AquaBuOY off the Northern California coast, with the floating power plant scheduled to start delivering energy in 2012.

"We're really looking to not only take advantage of the available renewable technologies that are out there that we can purchase energy from today, but also cultivating the next generation of technologies," said Zerwer.