Pacific Gas and Electric Co. (PG&E) was the most solar-integrated utility in the U.S. last year, followed by Southern California Edison and San Diego Gas & Electric, according to new rankings released last week by the Solar Electric Power Association (SEPA).

PG&E interconnected 85 MW of new capacity—a number representing 44% of the survey total, the trade group found in its “2008 Top Ten Utility Solar Integration Rankings”(PDF). The report surveyed 92 utilities, identifying those that have the most significant amounts of solar electricity integrated into their portfolio.

“This year, the report demonstrated that the utility segment is making a major investment to increase the amount of solar energy in power portfolios, with many utilities doubling the amount of solar power in their portfolio in just one year,” SEPA said. The overall installed solar capacity of the top 10 ranked utilities rose from 711 MW to 882 MW, reflecting a 25% growth. SEPA cited renewable portfolio standards, impending carbon policy, and fluctuating costs of power generation and fuel resources as primary factors driving this growth.

For the solar watts-per-customer category in 2008, the San Francisco Public Utilities Commission (SFPUC)—a water utility that provides electrical generation to its municipal buildings—ranked first with almost 2,700 W per customer for its 340 customer sites. Second and third were Kauai Island Utility Cooperative in Hawaii and Palo Alto Utilities in Northern California.

On a cumulative solar megawatt basis, Southern California Edison was ranked first, followed by PG&E, and Nevada utility NV Energy. In watts per customer, SFPUC ranked first again, followed by the Port of Oakland, and Southern California Edison.

The report also documents a wave of utility-driven installations, pointing to a new trend. Historically, the solar power market has been dominated by customer-driven installations.

Participating utilities had an average of 11 MW in their cumulative portfolio, and the top 10 utilities represented 93% of all solar capacity. Because of their head start, the large investor-owned utilities in California are likely to retain a lead in the overall cumulative rankings even as the year-to-year rankings shift, SEPA said.

“Residential and commercial photovoltaic projects will continue to be important stimulants for job creation and small business growth, but they will be complemented by large-scale photovoltaic and concentrating solar power projects,” said Mike Taylor, an author of the report and director of research and education at SEPA. “The variety of ways solar power is being implemented signals an increased maturity in the market.”

This year’s report shows that 2008 solar power growth came almost entirely from thousands of distributed generation projects, which grow more steadily and consistently than centralized plants. But SEPA anticipates that in future years centralized solar electric plants will play an equal or larger role.

Source: SEPA