Hawaiian Electric Co. worked to restore Oahu’s energy supply Tuesday after two of the island’s major power plants went offline and scheduled maintenance at another proved to be the perfect storm for rolling blackouts.
Separate problems at the AES and Kahe power plants and Kalaeloa Partners in West Oahu resulted in a loss of about 340 megawatts from Oahu’s grid.
Similar to the day before, HECO asked customers Tuesday to conserve energy between the peak hours of 5 and 9 p.m. as crews continued to work to restore the plants. Unlike Monday, however, HECO did not implement rolling outages that resulted in an estimated 27,000 customers in staggered areas losing power during that time period.
The offline power plants and the lack of wind to power Oahu’s wind farm created an unfortunate outcome, said Darren Pai, HECO spokesman.
"These are three of the largest generator units on the system," Pai said. "We had a number of things all coming together that put us in this unfortunate situation."
AES, an independent power producer, partially restored its generating station Tuesday to produce 82 megawatts of power after the plant went completely offline Monday due to a boiler tube leak. AES provides 180 megawatts and is the single largest generating unit on the island.
AES couldn’t be reached for comment.
HECO’s Kahe Power Plant also fell offline while Kalaeloa Partners’ oil plant was providing less than half of its maximum output of 208 megawatts as portions of the plant were disconnected for maintenance.
Crews had to replace equipment that failed in Kahe’s fifth generator, Kahe 5, of the six generators at the utility’s oil plant.
HECO crews were working to restore service to a 135-megawatt generating unit at the Kahe Power Plant on Tuesday.
"At this point we’re just working as quickly as we can to get the Kahe plant back to operating at full capacity," Pai said.
Independent power producer Kalaeloa Partners’ plant continues to operate at less than half its maximum output of 208 megawatts.
Hans Tobler, general manager for Kalaeloa Partners, said the unit was scheduled to be down for routine maintenance, but the problems at the other two plants could not have been predicted.
"Kalaeloa was meant to be offline. Every year we take one unit down with what we call a major overhaul," Tobler said. "Nobody could have known then that AES would fail and the HECO turbines would fail."
Kalaeloa Partners should be back to full service by next weekend, Tobler said.
Because of Hawaii’s isolated grid, overhauls of major power plants have to be planned for certain times of the year, said Alan Lloyd, a former engineer for HECO.
"We are like ships at sea. We can’t borrow from our neighbor," Lloyd said.
The overhaul for the Kalaeloa plant was scheduled at an appropriate time because the winter and spring are off-peak periods, Lloyd said.
The problems at the other plants during an overhaul are rare but not out of the ordinary, Lloyd said.
"It does not happen very frequently, but it is perfectly normal," he said.
These situations show how important it is to diversify Hawaii’s energy mix, Pai said.
"We will do everything we can to make sure the system is safe and reliable on a regular basis," Pai said. "As we look long term, as we move into this clean-energy future, we are going to need a new type of generation as we add more solar and wind power."
