UPDATE 1-California utilities issue RFPs for renewables

(Adds number of PG&E contracts from past RFPs, releads to mention purchased power agreements)

LOS ANGELES, June 30 (Reuters) - California's biggest utilities on Tuesday asked renewable power developers to submit proposals to them for new solar, wind and other renewable power plants, which would then be approved by the state next spring.

California utilities have largely chosen to foster renewable power plant development by signing long-term contracts, generally 20 years, with developers to purchase the power from renewable power projects, rather than to own the plants.

So far, Pacific Gas & Electric Co and Southern California Edison (SCE) are national leaders in securing renewable energy for power generation, spurred by California law that requires that 20 percent of the power they generate be produced from renewable sources.

Separately, the California Public Utilities Commission on Tuesday issued a report saying 156 megawatts of solar photovoltaic panels were installed in 2008, up from 81 MW in 2007. This is part of the California's $3.3 billion program launched in January 2007 with a goal of installing 3,000 MW of new solar projects in 10 years.

Another big yearly increase in installations is not expected.

In the first five months, 78 MW of solar capacity has been added, just slightly ahead of last year's pace.

This was the seventh annual open call for solar projects for SCE. Past requests for proposals has led to contracts for 48 renewable energy projects that can generate up to 27.3 megawatt hours of electricity a year.

PG&E has signed 60 renewable contract deals since 2002 that have production capacity of 5,477 megawatts.

Projects can be for wind, solar, biomass, biogas, oceanic, and geothermal power.

Proposals are due to the utilities in August and will come up for California Public Utilities Commission approval next April.

PG&E said it will hold a bidders conference on July 21. Contracts are due to PG&E on Aug. 24.

Large hydro projects are not included in the state's "renewable portfolio standard" because they are considered mature resource. Other states, including New York, which has projects at Niagara Falls, include large hydropower projects in counting renewable power.

PG&E is the main subsidiary of PG&E Corp (PCG.N). Southern California Edison is the main unit of Edison International (EIX.N). (Reporting by Bernie Woodall; Editing by Christian Wiessner, Bernard Orr)