Hawaiian Electric has run into power shortfalls and weather was not the culprit

During the past seven months, Hawaiian Electric has asked its Big Island customers nine times — sometimes for several days in a row — to reduce their electricity consumption during peak use hours in the evening.

The cause of the power problems was not the usual culprit: severe weather. The reasons:

• Generators unexpectedly tripping offline.
• Mechanical issues forcing power units offline.
• Facility or generator shutdowns at an independent power producer.

And sometimes these unplanned issues overlapped with scheduled maintenance on generating units.

“It’s never just one thing,” Hawaiian Electric spokeswoman Kristen Okinaka said. “It’s a combination of unusual situations.”

Electric customers heeded the call for conservation each time while the utility company corrected the issues or found other solutions, always in time to avoid a need for rolling outages — until the most recent emergency last week.

It all started the morning of March 14, when two Hawaiian Electric transmission lines unexpectedly tripped. That caused Hāmākua Energy, the island’s largest independent power producer with its generation facility in Honoka‘a, to disconnect from the electric grid.

It also resulted in about 35 percent of the utility’s 88,757 Big Island customers in various areas, from Hilo to Kona, Hawi to Nāʻālehu and many locations in between, to briefly lose power.

Okinaka said the problem was caused by an under-frequency load shed, which occurs during a sudden loss of generation. When such a load shed happens, protective devices automatically disconnect some customers temporarily to rebalance the available power supply with demand.

“This stabilizes the grid and maintains service for the majority of customers,” Okinaka said.

Power was restored within 5 to 20 minutes to most of those 31,000 customers affected. But the under-frequency load shed also caused damage that took Hāmākua Energy several hours to inspect and repair. That meant 60 megawatts of power it generates was unavailable to the island’s electric grid.

“When this type of trip occurs, the equipment cannot be returned to service immediately until inspections are performed … to ensure that the sudden and unexpected trip did not damage any of the equipment,” said Scott Valentino, president of Hāmākua Energy’s parent company Pacific Current Hawai‘i.

Hawaiian Electric’s Hill Plant unit No. 6 also went offline that day because of a mechanical issue. Combined, 80 megawatts of power were unavailable to the grid for most of the day. With wind resources also forecast to be near zero, the utility that afternoon issued its latest call for conservation during the peak hours of 5 to 9 p.m.

But the generation shortfall was too much. Despite conservation efforts easing demand, two rolling 30-minute outages were initiated between 7:20 and 8:06 p.m. About 8,580 customers in ʻĀinaloa, Pāhoa, Hala‘ula along ʻAkoni Pule Highway from ‘Iole Road to Niuli’i Place, some portions of Hawaiian Paradise Park and from Captain Cook to Hōnaunau briefly lost power so the island’s electrical system could be protected and to prevent loss of electricity to an even greater number of customers.

“The impacted areas and the timing of the outages were based on the amount of electric demand that needed to be reduced in real time,” Okinaka said. “The areas also are rotated so different areas are selected for this type of emergency outage.”

She added that the Hawaiian Electric system operations team, which manages the island’s electric grid, makes the decision to initiate rolling outages.

The utility was assisted by AES Waikōloa Solar, which provided about 30 megawatts to the island’s electric grid that night, in advance of its official commissioning. Hāmākua Energy also came back online just before 8 p.m., alleviating the need for rolling outages and power conservation. The No. 6 unit at Hill Plant also was back in operation by the morning of March 16.

Like with the previous calls for conservation and threats of rolling outages during the last few months of 2022, from the end of August to mid-November, many Big Island electric customers were understandably concerned as to why and if, when and where outages could happen. Some were upset by the localized blackouts.

“So customers are getting a break on that bill,” SZ Martin, with an angry emoji, replied to a post in the Hawai‘i Island Radio Scanner Community Facebook group. Another commenter on the same post replied with a meme that included one word: “OBSOLETE.”

“Recently [Hawaiian Electric] raised the prices for electricity,” said Sherri Keiko in a post in another Facebook group at 8:11 p.m. March 14. “Shouldn’t they use the funds from the increase to fix their aging machines?”

The utility in a press release later that evening apologized for the need to initiate the rolling outages and thanked its Big Island customers for their patience.

Hawaiian Electric has a total firm generation capacity of 280.5 megawatts on the island to provide power to it’s nearly 90,000 customers. It has another 168.6 megawatts of non-firm capacity that it can call upon as it becomes available. Okinaka said the utility, because of the nature of being on an island with “no one else to rely on,” has contingencies in place and always plans to have more generation available than needed.

However, it has faced several challenges during the past 12 months.

“We’ve had a number of situations where a large unit was down for scheduled maintenance and then another unit either developed a mechanical problem or became unavailable,” Okinaka said.

The 36.7-megawatt Puna steam unit, a reliable generator that Hawaiian Electric can normally count on, especially during the evening peak use hours, has been down for repairs since 2021. Some of the replacement parts haven’t been available, but fortunately it’s scheduled to be back online by June.

Puna Geothermal Venture, a geothermal energy power plant about 21 miles south of Hilo in the lower East Rift Zone of Kīlauea volcano, also hasn’t yet returned to its full production since the 2018 eruption and coming back online in November 2020. The plant normally provides 38 megawatts of power to the grid.

A number of mechanical issues at Hāmākua Energy, including several within the past seven months, also reduced Hawaiian Electric’s generation capacity. The facility in Honoka‘a has been generating electricity since 2000 and has experienced its share of normal wear and tear on equipment.

“Predictive and preventative maintenance on the plant’s various equipment is a routine exercise and as soon as any issue is identified, the plant’s operation staff have been diligent in conducting repairs and maintenance,” Valentino said. “While occasionally all or a portion of the plant may have to go offline due to equipment failure, the Hāmākua plant continues to generate energy to provide to Hawaiian Electric as it is called upon the majority of the time. All plants of this type have periods when they are not available due to unforseen equipment failures which lead to unanticipated forced outges for periods of time.”

He added that those issues become more visible when combined with other power generation facilities that also are experiencing problems. That kind of situation makes it so no single generation facility can cover the shortfalls of others.

For outage details or other Hawaiian Electric information, follow the utility on Twitter @HIElectricLight or visit the “Safety & Outages” page on its website, where you can find outage maps and more. To report an outage on the Big Island, call 808-969-6666.