Hawaiian Electric is asking customers on Hawaii island to reduce their electricity use until 9 p.m., saying it might be unable to meet tonight’s peak energy demand.

The utility said that three major generators on the island are not available, with two units at the Keahole power plant undergoing scheduled maintenance and a unit at Hill 5 that unexpectedly tripped offline. The units usually supply about 50 megawatts of power, Hawaiian Electric said.

Additionally, wind resources are forecast to be low.

Energy conservation can help reduce demand, offset any shortfalls and avoid the need for rolling, 30-minute outages, the utility said.

“Suggested steps include turning off or reducing use of lights and air conditioners, delaying showers, laundry and dishwashing activities, and going out for dinner or minimizing cooking until later in the evening,” Hawaiian Electric said in a news release today.

It’s also asking commercial customers like hotels to voluntarily reduce their energy use, placing maintenance personnel on standby to address unexpected issues and requesting maximum output available from the Puna Geothermal Venture.