Hawaiian Electric is once again asking Hawaii island customers to conserve energy, especially during peak demand from 5 to 9 p.m. today, due the unavailability of several large generators.

It is the second evening in a row that Hawaiian Electric is requesting energy conservation, following an initial request Thursday, because three major generators are out of commission.

“Last night, conservation efforts by households, businesses and government agencies helped ensure there was sufficient power to meet the evening peak demand, preventing the need for rolling outages,” said the company in a news release. “Hawaiian Electric asked its larger commercial customers, including government, hotels and retail, to voluntarily reduce electricity use. Hawaiian Electric thanks businesses for their help and asks the public to continue to patronize stores and restaurants tonight – they’ll still be open.”

Hawaiian Electric said its Hill 5 unit, which unexpectedly tripped offline on Thursday, was returned to service Thursday night.

However, two of its combustion turbine units at Kanoelehua and Puna, which normally supply about 32 megawatts of power, are offline with mechanical issues. Also, two units at the Keahole Power Plant, which usually supply about 36 megawatts of power, are undergoing annual scheduled maintenance.

Unfortunately, wind resources are forecast to be lower than usual.

Hawaiian Electric said by reducing demand, it can ensure enough electricity is available and prevent the need to initiate rolling, 30-minute blackouts to prevent a loss of power to an even greater number of customers.

If outages are necessary, Hawaiian Electric will notify customers in advance via @HIElectricLight on Twitter.