WAILUKU >> Maui Electric Co. has asked the state Public Utilities Commission to allow the utility to pass along a $155,000 cost for 1.4 gigawatt-hours of solar power that was produced but not used.

The utility in a Jan. 31 filing said it paid South Maui Renewable Resources $110,359.33 for 997.8 megawatt-hours of “compensable curtailed energy” per its power purchase agreement, The Maui News reported.

South Maui Renewable Resources has an annual energy contract for 6.75 gigawatt-hours, according to the filing.

Ku‘ia Solar, a 2.87-MW solar project, billed Maui Electric Co. for $44,803.80 for 405.1 MWh of compensable curtailed energy.

The filing said its total annual contract for energy is 6.6 GWh.

When asked for data on total curtailed power, total accepted power and percentage of curtailed power from South Maui Renewable Resources and Ku‘ia, Maui Electric Co. spokeswoman Sayble Bissen said the utility reports “do not separate energy usage by facility nor do they contain curtailment figures.”

Curtailed energy means power supplied but unused by the utility.

Updated figures will be submitted in the company’s “2018 Renewable Portfolio Standard Status Report,” which would include energy used from the South Maui Renewable Resources and Ku‘ia grid-scale solar projects, but their data would not be broken out, Bissen said.

Low-load modifications to heat-recovery steam generators on two of its Maalaea plant units also were cited by MECO in its filing as a method to integrate more wind and solar power. Modifications were made to the largest units at the Maalaea plant to allow them to run at loads lower than originally intended, Bissen said.

“Having the units operate at lower levels allows for us to accept more generation from renewable resources while maintaining the ability for the units to ramp up in response to any fluctuations in generation being produced by renewable resources,” she said.