Hawaiian Electric Co. is looking to build a 20-megawatt solar farm, a facility that the utility said will provide the lowest-cost solar power yet.

The electric utility said Monday it applied with the state Public Utilities Commission to develop a solar energy facility that would send power to the grid at 9.54 cents a kilowatt-hour. Two 2.87-megawatt solar farms on Maui, Kuia Solar and South Maui Renewable Resources, are the next lowest-cost projects in the state, at 11.04 cents per kilowatt-hour.

PUC approval is necessary for HECO to move forward with the project.

Darren Pai, HECO spokesman, said the price was low due to the decreasing costs associated with building solar projects. “Development costs for solar energy projects have fallen significantly in recent years,” Pai said.

The facility is to be built at Joint Base Pearl Harbor-Hickam, West Loch Annex. HECO is partnering with the U.S. Department of the Navy to get the facility up and running. If approved, HECO would build, own and operate the solar facility at the base. HECO said in exchange for the land, it will provide electrical infrastructure upgrades to Navy-owned facilities.

It is uncertain how much those electrical upgrades would cost. HECO did not respond to a request for an estimate Monday.

Jeff Mikulina, executive director of Blue Planet Foundation, cast doubt on whether the proposed farm would be the lowest-cost solar facility.

“Unlike most rooftop solar, with utility-scale projects, you have to look at the land costs,” he said. “It appears that the utility has worked out an agreement with the Navy to use the land at no cost in exchange for other system upgrades. Those upgrades must show up somewhere on the balance sheet.”

HECO said the $67 million project is expected to save ratepayers $109 million over the 25-year life of the solar facility. HECO said the savings are compared to what it would cost to use oil to generate Oahu’s energy. The renewable energy generated by the solar facility will serve all HECO’s customers on Oahu as well as residents on base.

“Thanks to the support provided by the Navy, this is a win-win for our entire community,” said Alan Oshima, president and CEO of HECO, in a statement. “It will save money for our customers, help the Navy achieve its renewable energy goals and get our state closer to 100 percent renewable energy at a reasonable cost.”

Pai said the facility could be used for a community-based renewable program. The program would help residents who do not have access to rooftop space save money on electric bills by allowing them to own a portion of renewable energy projects and get credit for the projects’ production.

“It will depend on the specifics in PUC’s directions for community-based renewables, but we believe it’s possible this project could play a role in that kind of program,” he said.

Depending on approval, construction could begin in January 2018 and the project could be in service by December 2018.

“Hands down, it is exciting to see the utility investing in our clean energy future,” Mikulina said. “Having solar energy at less than 10 cents is certainly exciting and, we think, it is a sign of things to come.”