The alternative of residential and business solar panels for electricity has grown rapidly in Hawaii, doubling in output each of the past five years, but a centralized solar power project proposed by a San Diego-based company could be enormous by comparison. Pending Navy cooperation, the state Public Utilities Commission should embrace such a project.

Navy coordination is needed because the company, Sempra Generation, wants to build the world’s largest solar power project on vacant Navy scrub brush land surrounding Pearl Harbor. The firm proposes to sell 90 percent of the electricity generated to Hawaiian Electric Co. and 10 percent to the Navy in return for use of the land.

In June, Sempra gained the PUC’s approval for a 20-year contract to sell 21 megawatts of wind power from its project in southeastern Maui to Maui Electric Co.

Its Pearl Harbor solar plan would contribute significantly to the state’s goal of generating 40 percent of its energy from renewable sources by 2030.

Electric companies now rely on slightly more than 20 percent of their energy from renewables, topped by about 42 percent by geothermal sources used by Hawaiian Electric Light Co. on Hawaii island.

Sempra figures that its solar output from Pearl Harbor would generate 300 megawatts of electricity, providing 8.3 percent of the 7,300 gigawatts of electricity consumed last year on Oahu, where renewable energy accounted for 16.6 percent of electrical consumption.

"But the cable is expensive," said Mitch Dmohowski, Sempra’s director of commercial development. "This can be done a lot cheaper. It can be done for 25 percent less, and it can be done in three years."

Sempra’s solar project is estimated at $1 billion, the projected cost for Big Wind’s cabling alone.

While the Big Wind proposal has drawn opposition from environmental and community groups on Maui and Lanai, Sembra’s solar plan appears less controversial.

One possible snag is that munition storages are located in the middle of Sempra’s proposed site, classified by the Navy as "explosive arcs" where the Navy restricts development, according to Greg Gebhardt, director of the Naval Facilities Engineering Command’s Energy Office.

"I’ve heard that the Department of Defense or the Navy might give some relief because of the push for renewables," Gebhardt told the Star-Advertiser’s Alan Yonan Jr.

He said he hopes the site receives an exemption, noting that Sempra would be a "prime candidate."

While Sempra is experienced in such ventures — notably its operation of an Arizona solar facility that is the nation’s largest, and another in that state that will be the world’s largest when finished — its Hawaii plan is in the early stages.

Next month, HECO will open bidding for 200 megawatts of renewable energy production, and Sempra’s timetable dovetails.

All this will necessitate closer looks by the PUC before going forward, but the signs are encouraging.