After two waves of rolling power blackouts, Hawaiian Electric Co. said no further outages would be needed Monday night.

Power was restored in Hawaii Kai and Laukahi, and sections of Waimanalo, Waialae Iki, Aina Haina, Niu Valley and Kuliouou at about 7:45 p.m. in a second wave of rolling outages that began in the downtown area.

The first wave, which kicked in about 6:25 p.m., affected the Nuuanu and School Street areas, where in addition to residential power loss, the outages also affected traffic signals. Traffic backed up in the blackout area as well as on nearby Punchbowl Street and Vineyard Boulevard.

An estimated 27,000 customers were affected by the rolling outages, but no more than 14,000 at one time, HECO said.

“We thank our customers for their patience, understanding and efforts to conserve power. We deeply apologize for the impact of these outages, especially to those who were watching tonight’s football game,” said Darren Pai, Hawaiian Electric spokesman.

Customers in areas that have been restored but are still out of power are being asked to call HECO to make a report at 1-855-304-1212.

HECO had said outages were projected to last about one hour and rotate through various parts of the island. 

The company had said it expected to have outages in other areas, including most of Waipahu, and sections of Pearl City, Kunia, and Ewa but announced at about 8:30 p.m. that no further areas would be affected. 

According to a news release issued by HECO, the rolling outages were necessary to ensure the demand for power did not exceed the amount of available generation, which could have resulted in an islandwide outage.

HECO asked Oahu customers to assist with the situation by conserving electricity use until about 9 p.m. to ensure sufficient power was available to meet the early evening peak demand for electricity. Suggested steps included turning off or lessening use of air conditioners, delaying hot showers and dishwashing activities, and minimizing cooking until later in the evening.

The loss of several generating units, including the largest on the island operated by independent power producer AES, required Hawaiian Electric to briefly shut off power for about 10 minutes to about 22,000 customers at approximately 1:50 p.m. The outages affected customers in areas across the island, including Kailua, Kaneohe, Maunawili, Wailupe, Halawa, Makalapa, Waipahu, and Waimano. Power to most affected customers was restored shortly after 2 p.m.

The targeted emergency outages were necessary to avoid a more widespread outage or damage to the electric system from an imbalance of too much demand versus too little available generation.

The outage occurred after a 180-megawatt power plant operated by AES, an independent power producer, unexpectedly went out of service. 

In addition, the Kalaeloa Power Plant, also owned and operated by an independent power producer, has been providing less than half its maximum output of 208 megawatts as it goes through repairs for an equipment problem. One of Hawaiian Electric’s generating units at the Kahe Power Plant, which normally produces 135 megawatts, is also off line after it unexpectedly experienced problems this morning.

The loss of generation prompted HECO’s rolling outages, said Darren Pai, Hawaiian Electric spokesperson.

“We apologize for this disruption and thank our customers for their patience. We understand the evening hours, especially today with the football game, are an especially inconvenient time to cut back on electricity, but with everyone’s help we hope to avoid an emergency situation,” Pai said in the release.