The latest solar rankings for U.S. utilities are in.

The 2013 rankings were recently released by the Solar Electric Power Association (SEPA). They are based on how many new megawatts of solar utilities built in 2013 and how many megawatts per customer they have installed.

The listed utilities accounted for 82 percent of all new solar capacity in 2013, up from 73 percent in 2012. The top builder of new solar in 2013 was once again California's Pacific Gas and Electric Company, which has led for six of the seven years that SEPA has conducted the survey.

San Diego Gas and Electric Company, a newcomer to the top ten, was second; Arizona Public Service moved up to third. Both brought significant utility-scale capacity on-line last year, including APS’ landmark Solana Generating Station solar power tower with molten salt storage.

Southern California Edison dropped from second place to fourth, and Public Service Electric and Gas of New Jersey dropped from third to seventh place. Both utilities are focused on rooftop solar as much as they are utility installations.

Also returning to the top-ten list for new megawatts were Hawaiian Electric Company and Duke Energy Carolinas, while Duke Energy Progress, National Grid, and Georgia Power made the rankings for the first time.

A few years ago, the integration of 10 megawatts would have placed a utility on the top-ten list. In 2013, 57 utilities added 10 megawatts or more, according to Mike Taylor, SEPA's director of research. These numbers indicate solar is becoming a factor that utilities across the country must actively prepare to manage.

One caveat: the utility-scale projects that drove 2013’s big numbers are the result of pipelines established over the last three to four years by utilities looking to meet renewables mandates. They do not seem to be growing a new pipeline of large projects.

The 2013 rankings were based on responses from 287 U.S. utilities, up from 256 utility responses in 2012.

The watts-per-customer ranking list, which give small utilities, munis and co-ops the opportunity to shine, was topped by Sterling Municipal Light Department, a public power utility in Massachusetts that serves only 3,700 customers.

“The Sterling Light Commission, employees, Sterling Selectmen and Planning Board, our business partners, E.H. Perkins, CES Sterling LLC, INDU Solar Holdings, groSolar, as well as many others, all played a role in creating a public-private partnership that included an educational piece for our local schools,” said Sean Hamilton, Sterling's general manager. "The whole town can be proud.”

Sterling’s projects are co-owned by module manufacturer Canadian Solar and INDU Solar Holdings. INDU is a joint venture of Duke and Integrys Energy.

SDG&E and Silicon Valley Power followed Sterling in watts per customer, with APS, HECO, PG&E, Hawaii Electric Light, Maui Electric Company, Kauai Island Utility Cooperative, and Imperial Irrigation District rounding out the top ten.

Hawaii’s small utilities, especially HECO, dominated the watts-per-customer rankings due to a solar surge in the state. However, HECO has been attacked by The Alliance for Solar Choice and other solar advocates for obstructing solar progress as the utility attempts to manage the high levels of solar on many of its circuits. 

HECO pointed to the utility’s consistent ranking among the top builders of megawatts per customer -- it was fourth last year and fifth this year -- and said it is dealing with unprecedented levels of solar penetration that other utilities are just beginning to think about.

Tags: arizona public service, hawaiian electric company, new megawatts of solar, pacific gas and electric, san diego gas and electric, solar electric power association, sterling municipal light department, utility scale solar, watts per customer