Oahu customers are asked to reduce their electricity use between 5 p.m. and 9 p.m. Friday to help keep the lights on.
Hawaiian Electric said high temperatures and humidity are increasing power use at the same time overcast skies have lowered solar power generation. Wind power resources are also low, according to the company.
Friday morning's lightning storm damaged transmission lines from two wind generators, and the H-Power plant and other generators are offline or operating minimally because of the rain or lightning. The company said the equipment is being repaired but will not be up for tonight's peak period.
"If we were to lose another large generating unit during the peak hours, we would be in an emergency situation and would have to begin brief rolling blackouts," Hawaiian Electric spokesman Jim Kelly said in a news release.
"This is an unusual situation and we appreciate the support of our customers - every bit we conserve really helps."
