Hawaiian Electric Co. said seven planned large-scale solar projects could save customers more than $800 million and would allow the expansion of customer-sited rooftop solar.

HECO argued for approval of the projects in response to a state Public Utilities Commission decision earlier this month to defer the projects.

PUC Chairman Randy Iwase said he delayed approvals of the solar projects, totaling 220 megawatts, because HECO did not provide enough information to prove the projects were beneficial to ratepayers.

HECO had asked the PUC to waive competitive bidding rules for the solar projects to help shorten the approval process and assure the projects would make the deadline for a 30 percent federal tax credit. The solar projects have to be in operation before December 2016 to qualify for the tax credit.

Iwase said he needed more information from HECO before approving the projects, including:

» The impact the solar farms would have on the grid.

» The customer savings.

» A priority list for the seven projects if some could not be connected.

In its response, filed with the PUC on Friday, HECO said the contracts between the utility and the different power producers could save customers more than $800 million over 22 years, according to a high fuel cost scenario, or could cost more than $9 million, according to a low fuel forecast.

Hawaiian Electric believes the likelihood of the downside risk to be low because fuel prices would have to drop below even today’s low levels to result in a cost to ratepayers.

HECO said it is essential for the project to qualify for the federal tax credits to achieve the projected customer savings.

"Hawaiian Electric continues to believe that all of the waiver projects can be completed and in service by the end of 2016," the utility said.

HECO said all of the large-scale projects could be safely connected to the grid on Oahu, and HECO could resolve any technical issues.

"All of the waiver projects can be safely integrated onto the Oahu system grid while still accommodating and permitting continued growth of customer-sited PV systems," HECO said in the filing.

In response to the commission’s request to prioritize the seven projects, the utility rated the projects either "ideal circumstances," "better than average" or "neutral."

HECO would not reveal the information publicly. The utility said the rankings could potentially affect the contracts with the project developers.