UPDATE, 5 P.M.

The risk of rolling power outages on Oahu this evening due to reduced generation has been lowered, but Hawaiian Electric is still asking customers to conserve electricity to avoid shortages tonight.

The utility company said it may be forced to impose rolling blackouts starting at about 10 p.m. due to an unexpected shutdown of a 208-megawatt power plant operated by Kalaeloa Partners — the largest, independently-owned power generator on the island.

Earlier today, Hawaiian Electric warned of possible outages starting at 6 p.m. and lasting 30 minutes to an hour for different parts of the island at different times.

Since the earlier announcement, issued at about 2 p.m., Hawaiian Electric has been able to bring back a generating unit at one of its own power plants that was down for scheduled work.

“Previous demand forecasts predicted insufficient generation earlier in the evening, but Hawaiian Electric crews were able to ramp up additional generation resources at Kahe Power Plant and expect that large-scale battery storage will help provide power to all customers through the evening peak,” the company said in a statement.

3:25 p.m.

In response to the scheduled Hawaiian Electric rolling outages tonight, the Honolulu Board of Water Supply is asking customers from the Leeward Coast to Kahala and Mililani to begin conserving water immediately.

The board plans to reduce pumping capacity to lower electrical demand when pumping water.

“BWS customers are being asked to conserve water and use only for cooking, drinking, and personal hygiene. Please hold off on non-essential uses such as car washing, watering plants and lawns, and doing laundry until further notice,” according to a news release.

EARLIER COVERAGE

Hawaiian Electric this afternoon said due to a shortage of generation capacity, it may be forced to turn power off in select areas of Oahu and implement rolling outages, starting at 6 p.m. today.

“Based on current demand forecasts, Hawaiian Electric will not have sufficient generation during the evening, when customer demand is highest,” said the utility in a news release. “To balance the amount of generation and demand, customers should prepare for rotating outages in various parts of the island lasting approximately 30 minutes. The duration of any outages may vary depending on the amount of generation available at the time.”

The utility said the generation shortfall is due to the unexpected loss of the 208-megawatt plant operated by Kalaeloa Partners — the largest, independently-owned power plant on the island.

At around 1 a.m., the plant suddenly went offline, with the rupture of an underground pipe necessary for operations, Hawaiian Electric said. Kalaeloa Partners expects repairs to its plant to possibly take three days.

“Hawaiian Electric is using companywide resources and working to return generating units to service as soon as possible,” said the utility in the release. “Customer conservation will also help.”

Hawaiian Electric is asking customers, including hotels and large commercial customers and residents to reduce their use of electricity, especially during the peak evening hours of 5 to 9 p.m.

Hawaiian Electric also recommends that residential customers turn off air conditioners and unneeded lighting, shut off water heaters and pumps, and shift activities like cooking, showering, laundry, and dishwashing to the daytime, when solar is abundant.

Customers are also advised to turn off and unplug any unnecessary electrical equipment, especially sensitive electronics, to prevent damage when power is restored after an outage.

If needed, the approximately 30-minute outages will rotate through the following areas in the following order:

>> Waipahu, sections of Pearl City, Kunia, Ewa Beach

>> Waiawa, Crestview, Mililani, Kunia, Waimalu, Upper Kipapa areas

>> Pearl City, Waimalu

>> Majority of leeward areas

>> Lower Kalihi, sections of Upper Kalihi

>> Kakaako

>> Sections of Kahala

>> Sections of Kaimuki and Kapahulu

>> Majority of Kaimuki, sections of Kapiolani Boulevard and Waikiki

>> University of Hawaii Manoa campus, Manoa

>> Nuuanu and School Street area

Due to recent large outages in the downtown, Chinatown and Hawaii Kai areas, those neighborhoods are not included in the outage rotation today.

Roughly 20,000 customers in Hawaii Kai were out of power early Tuesday morning, and roughly 490 waited until this morning for power to be restored. Hawaiian Electric posted on X that power was restored to those customers at about 12:20 a.m. after crews worked on underground cables.

Hawaiian Electric said the situation is dynamic, and that updates would be provided via its social media channels.