The biggest electric utility in Hawaii has had an extraordinary challenge this year keeping the lights on for the biggest island in the state.

Hawaiian Electric resorted to rolling blackouts on Hawaii island once in January and once in February, and on March 25 issued a plea for customers to reduce or shift electricity use to help avoid forced outages through mid-April.

The company has been facing an unusual situation with mechanical problems at three of the island’s five largest power plants while part of the largest plant undergoes an annual overhaul. All four of these affected power plants are owned by the utility or an affiliate of its parent company.

Also contributing to the trouble is lower output from a geothermal plant, which has the third-largest generation capacity on the island and is owned by an independent operator.

“This is an unusual situation, driven mainly by the unavailability of several large generators that have experienced mechanical problems, are at reduced output, or are undergoing maintenance,” Hawaiian Electric said in its March 25 announcement asking customers to use less electricity, especially on weekdays from 5 to 9 p.m.

The company explained that it faces an “extremely tight” supply of power at peak use periods, especially when production from wind, solar and hydroelectric facilities is lower than normal. Those sources of variable, renewable energy can supply up to 15% of electricity needs on the island.

“Without enough supply to meet electricity demand, the company may initiate rolling outages of up to an hour around the island,” the March 25 announcement said.

Hawaiian Electric, which posts service information on its X social media account, even partnered with Hawaii County Civil Defense after the February rolling blackouts to have energy conservation requests and rolling outage alerts broadcast on the radio and to emergency notification subscribers through alert distribution firm Everbridge.

The predicament generated concerns over whether the power would stay on for the weeklong Merrie Monarch Festival for hula in Hilo last week, and upset customers after the forced January and February outages.

“Just used to the 3rd world power company by now!” Brandon Belmarez posted Feb. 16 on X, formerly Twitter, using the hashtag #bigislandoutage during an outage three days after rolling blackouts.

System makeup

The utility, which serves about 90,000 Big Island customers through Hawaii Electric Light Co., typically maintains 30% more production capacity from firm power sources, mainly oil-­fueled generating units, than needed for peak demand.

This reserve margin equates to roughly 56 megawatts of firm power. But this year the margin has been low, and twice wasn’t enough to cover demand.

Firm generation capacity on Hawaii island totals 280.5 megawatts, and nearly all of it comes from six power plants, of which five are owned by the company or its parent. These six plants can each deliver between 21 and 77.6 megawatts of electricity.

Hawaiian Electric also can receive up to about 78 megawatts from six renewable-­energy production facilities that range from a 1.1-megawatt hydroelectric plant to a 30-megawatt solar farm where generation normally varies by weather conditions.

Many customers also generate some of their own power. There are about 17,000 rooftop solar systems on the island.

It is normal for some generation sources to be out of service for routine maintenance, and occasional equipment breakdowns usually can be covered by reserve capacity.

This year, however, too many problems with too many power sources have made the adequate supply of electricity on the island precarious.

The single biggest problem has been a 60-megawatt Hamakua Energy Partners plant. This facility, owned by an affiliate of Hawaiian Electric’s parent company, is the second-largest power plant on the island and roughly equates to the utility company’s firm power reserve margin.

Breakdowns

Trouble at Hamakua Energy appeared Dec. 30 when output fell because of an unknown cause, according to a March 11 report from Hawaiian Electric to the state Public Utilities Commission.

Operating problems at the plant got progressively worse in January, according to the report, which redacted information about the size of output drops for competitive reasons.

On Jan. 30, the utility cut power to groups of customers around the island for 30 minutes at a time. The rolling blackouts were necessary to prevent losses for greater numbers of customers if demand was allowed to exceed supply.

Supply on Jan. 30 was critically low because on top of Hamakua Energy’s reduced output, three generation units at other power plants tripped offline, including two that normally generate 32 megawatts of power. Also, a 14-megawatt unit at the utility’s Hill Plant was under repair, and almost no wind existed to drive two wind farms with a combined capacity of 31 megawatts.

The rolling outages ended by 4:30 p.m. that day, and Hawaiian Electric lifted a request for customers to conserve electricity after restoring enough generation for peak evening use.

About two weeks later, on Feb. 13, more rolling blackouts were initiated after Hamakua Energy suffered a complete outage while two other generation units — the same Hill Plant unit and a 15-megawatt unit at the 36.7-megawatt Puna Steam plant were under repair — and a 21-megawatt unit at the 77.6-megawatt Keahole power plant was undergoing annual maintenance. Wind resources also were forecast near zero that day.

The Feb. 13 blackouts only lasted for about three hours in the evening. Still, a precarious supply has persisted largely due to Hamakua Energy, which after partial service restoration went back offline Feb. 29 and remains out of service.

Pacific Current, an affiliate of Hawaiian Electric Industries Inc. that bought Hamakua Energy in 2017 from a private equity firm and assumed a contract to sell power to Hawaiian Electric through 2030, said in a statement that one of the plant’s two generation units is being replaced with a new unit.

“Hamakua Energy is focused on returning to normal operation as soon as possible,” Pacific Current officials stated. “We have invested in a brand new generator, which will replace one of two offline generators. It is expected to restore approximately 50% of the plant’s energy generation capabilities once online.”

Pacific Current does not yet have an estimate on when the new generator will be in operation.

Meanwhile, Hawaiian Electric estimates that the 21-megawatt generation unit at its Keahole power plant will be back in service by the middle of this month after its annual overhaul is complete. This should allow the company to lift its current customer power conservation request.

Long-term plans

In the longer term, a mix of more firm and renewable power is in the works for Hawaii island.

A 30-megawatt solar farm with battery storage, Hale Kuawehi Solar, is under construction and may be ready for operation in October after supply chain delays and other problems prevented the project from being done by late 2022 as previously planned by its developer, Innergex.

Another long-delayed grid addition involves an existing 38-megawatt geothermal power plant.

The Puna Geothermal Venture plant owned by Ormat Technologies was taken offline in 2018 as lava flows threatened and then overran parts of the facility. Ormat restored partial service in 2020 and at that time expected full production to resume by mid-2021. However, Ormat reported that last year, production averaged only 26 megawatts and reached 30 megawatts in October.

Before the 2018 volcanic eruption, Ormat planned to boost the plant’s capacity to 46 megawatts by late 2019 or early 2020. More recently, Ormat projected this additional capacity will come online in 2026.

Renewable energy companies also are working to develop three solar farms on the island with a combined production capacity of 201 megawatts and battery storage, projected to come online between 2028 and 2030 as part of an effort for Hawaiian Electric to achieve 100% of power statewide from renewable resources by 2045.

One new addition to Hawaii island’s grid that didn’t happen in recent years as once expected was a 30-megawatt power plant to run on biofuel.

This project by Hu Honua Bioenergy LLC received PUC approval in 2013, but work by the company to convert a defunct sugar mill power plant to run on eucalyptus trees growing along the Hamakua Coast as well as other woody plants suffered delays that led Hawaiian Electric to cancel its contract with Hu Honua.

A revised contract was agreed to and approved by the PUC in 2017, but environmental organization Life of the Land challenged the approval over greenhouse gas emission impacts. Ultimately, the PUC rejected the project in a 2-1 vote and the Hawaii Supreme Court in 2023 upheld that decision.

Hu Honua, citing the recent power instability, asked the PUC in a letter Monday to direct Hawaiian Electric to negotiate a new contract with Hu Honua for PUC approval so that the 99% complete $520 million biofuel plant can feed power to the grid.

“This electric power crisis never had to be and it does not have to continue one day longer,” Warren Lee, Hu Honua president, said in the letter.

Henry Curtis, Life of the Land executive director, said he is concerned about Hawaiian Electric reliability on Hawaii island but opposes any special approval being given to Hu Honua outside of a normal regulatory proceeding.

PUC officials declined to comment on Hu Honua’s letter, but said the commission has directed Hawaiian Electric to bring online new firm and variable renewable energy projects as quickly as possible, and that it has mechanisms in place to assess penalties for delays.