Consumer-installed solar electric systems on Oahu, the Big Island and in Maui County more than doubled in 2010 with 3,967 systems added, compared with 1,916 in 2009.

"This will help all of us in Hawaii as we continue to make progress in cutting our dependence on imported oil," said Robbie Alm, Hawaiian Electric Co. executive vice president, in a statement.

The installations have increased the state’s electric generation capacity by 13 megawatts, enough to power 3,350 homes.

Alm commended the solar industry for "helping make Hawaii a solar leader."

"Coordinating with them, we have worked to make solar power more accessible for our customers," he said.

Some 17 new large-scale photovoltaic projects will sell electricity back to Hawaiian Electric. They will produce 3.2 megawatts.

However, all for the solar industry is not sunny, as regulations limit the number of customers that can easily install solar and integrate with their island’s utility.

"The irony here is while we in the industry gratefully accept HECO’s congratulations for having a strong year in 2010, at the same time we in the industry are seeing more and more circuits being effectively closed to more PV," said Marco Mangelsdorf, president of Hilo-based ProVision Solar Inc.

Once a residential area reaches a certain threshold of energy-generating customers, additional residents wanting to sell power to the utility have to pay for a reliability study, Mangelsdorf said. Those can cost $2,500 for an individual residential customer, while commercial customers can pay tens of thousands of dollars.

HECO has produced detailed maps customers can access online to determine whether their area is at or near the generation threshold.

Meanwhile, the government, utilities and solar industry continue working "to set some reliability standards," said Darren Pai, HECO spokesman. The parties are examining "what can be done to increase the amount of these variable resources we have on the system and make sure we can integrate them all reliably and safely."