UPDATE: 6:15 p.m.

Kauai Island Utility Cooperative officials say they have identified the cause of Sunday’s islandwide power outage, which led to rolling blackouts today.

Utility executives said the 27.5 megawatt combustion turbine at the Kapaia generating unit had a cable failure, tripping a generator breaker which caused “a cascading effect on other generation sources” and an islandwide blackout for more than 2 hours Sunday evening.

Rolling blackouts were needed Sunday and today because other electricity-generating units were out of service for either repair or scheduled maintenance, officials said. Electricity customers experienced 30-minute outages every three to four hours during the rolling blackouts, which are expected to last until 11:00 p.m., and possibly Tuesday morning.

“The lack of sun today was a real challenge, as we had virtually no production from our large solar facilities,” said KIUC President and Chief Executive David Bissell. “On top of that, we have increased demand from residential and commercial rooftop solar customers whose systems aren’t producing.”

Company officials say they hope that the rolling blackouts will no longer be need after Tuesday. “However, logistic or mechanical issues combined with continued expected cloudy weather could cause an extension of the blackouts,” they said in a news release.

10:40 a.m.

About 10,000 Kauai residents from Kekaha to Princeville dealt with rolling electric outages between 6 a.m. and 7:30 a.m. today, and utility officials are asking everyone to reduce energy use after Sunday’s islandwide power outage.

Kauai Island Utility Cooperative’s largest generator, Kapaia Power Station, is inoperable due to that outage, according to a statement from the utility. Several units at Port Allen Generation Station are also down for repair or maintenance.

The Wainiha hydro units have been out of commission since Sunday’s outage and an approaching storm will limit solar productivity, KIUC said.

“We appreciate our members’ cooperation to conserve power and their continued patience as we perform repairs to our system,” the utility said.

A status update on the Kapaia generating unit is expected later today. KIUC’s Facebook page will also have the latest information.

7:40 a.m.

Kauai Island Utility Cooperative officials said electricity customers should expect rolling blackouts this morning following an islandwide power outage Sunday afternoon.

“Members in affected areas should experience no more than a 30 minutes outage between now and 10:00 a.m. We appreciate your patience,” the utility said in a news release early this morning.

KIUC members are asked to conserve power to reduce the load.

Previous coverage:

The Kauai Island Utility Cooperative said Sunday there was an islandwide power outage at about 2:30 p.m., when the main generating unit at its Kapaia Power Station had a problem.

“The outage also impacted functionality of KIUC’s phone system,” the utility said. “As of 4:30 pm, roughly 90 percent of KIUC’s members had been restored. We continue to restore customers as additional generation units come online.”

The cause of the outage is still under investigation.

KIUC said the outage left its largest generating unit inoperable.

“As a result, generation capacity is limited as we move into our evening and morning peak periods. If load exceeds generation capacity, we may need to implement temporary rolling blackouts,” the company said.