Utilities are embracing more solar system than ever in their portfolios, not just with third-party installations by businesses and homeowners, but through their own acquisitions of projects.

That’s according to the recent Solar Electric Power Association (SEPA) 2011 Utility Solar Rankings Report. The report ranks utilities by region and type, whether it is an investor-owned utility of municipally owned.

The report showed that in 2011, utilities interconnected more than 62,000 PV systems of all sizes. These new systems resulted in almost 1,500 MW of new utility solar capacity, more than twice as much as was added in the previous record year, 2010.

“In addition to the photovoltaic systems added by customers and third-party producers, much of the growth has come from the direct actions of utilities,” said Julia Hamm, SEPA President and CEO. The findings show that 39 % of new solar capacity came from utilities owning or contracting for solar power. Large solar projects, greater than 10 MW each, represent the bulk of this utility-led capacity. The remaining 61 % comes from residential and commercial installations.

The SEPA rankings cover more than 240 of the most solar-active utilities representing more than 99% of the U.S. solar electric power marketplace.

Some key trends include:

Thirteen utilities interconnected more than 1,000 PV systems and 22 interconnected more than 500 systems. To put this in perspective, about 350 non-solar power plants (> 1 MW) were expected across the entire U.S. in 2011. Conservative forecasts indicate that this number will grow to more than 150,000 interconnections in 2015.

The magnitude of these numbers poses strategic questions related to how utilities will physically process this volume of interconnection requests, how the distribution grid will accommodate this high-penetration growth, and how the utility and solar industries will resolve the economic implications of reduced sales of electricity.

For the fourth straight year, utilities integrated a record amount of new solar power, despite the recession. The nation’s most solar active utilities integrated almost 1,500 MW of new solar, equivalent to six natural gas power plants, breaking the 1 GW threshold for the first time. Fifteen utilities reported integrating more than 20 MW each, and eight reported more than 50 MW each. While residential homes accounted for more than 89% of the installations, commercial rooftop installations accounted for more than 53% of the capacity.

Utility-driven procurement represented 39% of the new solar capacity in 2011, versus 9% in 2008. As compared to the more traditional customer-oriented market segment, this sector consists of direct wholesale purchases and utility-owned projects, which were 26% and 13% of the market respectively. Large solar projects (> 10 MW) make up the bulk of this capacity with an estimated 18 projects totaling 332 MW, up from 226 MW in 2010. SEPA anticipates that this utility segment could increase to 1500 MW in 2012, equivalent to the 2011 market in its entirety.

Among utilities, Pacific Gas & Electric (PG&E) ranked first and installed 288 MW. It added three utility-owned projects totaling 50 MW, integrated 13,600 customer-sited projects and added a 150-MW power purchase agreement with the largest project completed in the U.S. in 2011. Public Service Electric & Gas (PSE&G) ranked second with a 181 MW portfolio, a 142% growth over 2010. Their portfolio was 83% distributed projects and 13% utility-owned.