It’s power crunch time on Oahu.

Less than a year from now, Hawaiian Electric is slated to retire the island’s largest and dirtiest power plant as part of a historic ongoing transition to more renewable clean energy.

However, outside concerns still exist about whether the unprecedented and technically complicated switch will go off without a hitch.

State officials have been trying to push the regulated utility to maintain or accelerate development timetables for solar farms and energy storage facilities planned by other companies after some of these renewable energy developers encountered delays for projects that could be needed to keep the lights on after the scheduled Sept. 1 shutdown of a coal-fired power plant.

As part of the effort, an idea was even floated recently to burn wood pellets imported from Canada at the 180-megawatt coal plant, which is owned by AES Corp. and satisfies 16% of Oahu’s peak power needs, though Hawaiian Electric dismissed the proposal as unnecessary.

Leaders of the utility are extremely confident that their transition plan — which includes changes to maintenance schedules for its old oil-burning power plants so that they aren’t out of service before enough new solar farms and batteries come online — will be carried out without any power supply shortfalls.

“I think we’re in a good place to be able to keep the lights on and continue to serve load reliably from our generation systems even if some of those (new power sources) were not to happen or were to be delayed,” Colton Ching, Hawaiian Electric senior vice president of planning and technology, said during a June state Public Utilities Commission briefing.

According to the utility, its reserve power capacity next year wouldn’t drop below what it regards as a safe buffer, around 200 megawatts, if none of the renewable energy projects expected next year are delivered.

“We feel like the plan has enough meat to it,” Scott Seu, Hawaiian Electric president and CEO, said during the June briefing.

PUC Chairman Jay Griffin, a former Hawaii Natural Energy Institute faculty member whose research has included renewable energy distribution technology, expressed a less confident view.

“We’re still not clear how we’re going to get through next September, next fall,” he said at the same meeting. “The timing of a number of these (planned solar and battery) projects is critical throughout the (2022 and 2023) time frame.”

State Sen. Glenn Wakai, chairman of the Senate Committee on Energy, Economic Development and Tourism, held a joint information briefing with the Senate Ways and Means committee Sept. 29 to evaluate the idea of retrofitting the AES coal-fired plant to run on wood biomass.

“The two chairs,” Wakai said, referring to himself and state Sen. Donovan Dela Cruz, “have some concerns about the fact that we’re going to say goodbye to about 20% of our base load power generation next year with the closure of the AES coal plant, and aren’t really confident that we have a clear game plan as to how we are going to fill the puka (hole), so to speak, with renewable energy, with petroleum or what the future may hold.”

Initial alarm

Early concerns from the PUC were triggered around the end of 2020 when it learned that projected delivery dates for some renewable energy projects were being delayed largely by technical studies that are needed to ensure connections to Oahu’s power grid are workable.

In response, the PUC launched a proceeding in February to continually monitor the status of renewable energy projects where delays could seriously jeopardize cost-effective retirement of the coal plant and reduce reliability of Oahu’s electrical grid.

Hawaiian Electric in March let the PUC know that despite setbacks, it had a good handle on moving into what it called “uncharted territory” of replacing one long-running power generation workhorse with a mixture of new technology plugged into different spots on a grid not designed for such a change.

The company said it wasn’t solely responsible for delays or the risk of delays, given that renewable energy developers were making equipment changes that created potential ripple effects on other projects that needed additional study to avoid negative impacts.

“The interconnection process and review are absolutely mandatory to ensure a project’s successful interconnection to Hawaii’s grid,” the utility said in a PUC filing. “The process is complex, evolving and vitally important in order to maintain the quality of electric power (we) strive for and customers expect.”

Hawaiian Electric cited progress in shortening interconnection study times, and offered a list of contingency plans that could ensure reliable service continues after the coal plant shuts down even if new projects are delayed.

The company’s response drew some critical comments, as well as suggestions, by the state Consumer Advocate and local organizations supporting clean energy, including Blue Planet Foundation, Life of the Land and Ulupono Initiative.

On March 30, Gov. David Ige also formed a “Powering Past Coal Task Force” led by the head of the Hawaii State Energy Office to collaborate on achieving the goal.

Key projects

The timing of the coal plant’s retirement has alarmed some observers because power consumption in September is greater than in any other month.

Not retiring the coal plant isn’t an option because state lawmakers fortified the Sept. 1 date in a law enacted in 2020 after Hawaiian Electric’s 2016 decision not to extend a power purchase agreement with the plant’s operator as part of working to fulfill the state’s goal of having 100% renewable energy generation by 2045.

So, a few big planned renewable energy projects were intended to support a successful transition past the coal plant’s shutdown, particularly in the fall of 2022 and 2023.

One key project is a 185-megawatt energy storage complex in Kapolei initially scheduled to begin operating in June 2022, three months before the coal plant’s retirement date.

The Kapolei battery project would about equal the coal plant’s power capacity by storing energy produced in daylight hours by new solar farms, or oil-fueled generators initially if necessary, and distributing the energy during peak evening demand.

Three solar farm projects with battery storage are also expected to be gene­rating power next year: a 39-megawatt facility in Mililani and a 36-megawatt facility in Waiawa by San Francisco-based Clearway Energy Group, and a 13-megawatt facility in Kapolei by AES.

None of these four projects have encountered delays over government permitting or supply chain issues with availability of materials, according to Ching.

Meanwhile, recent efforts to advance delivery dates are paying off for some of these projects.

Projected start dates advanced to July 2022 from November 2022 for the Mililani solar project and to September 2022 from December 2022 for the Waiawa solar project, both of which are in early construction.

The AES solar project’s operating date is unchanged at September 2022.

The Kapolei battery project by San Francisco-based Plus Power is delayed. Though the developer held a ceremonial groundbreaking in August, major construction is scheduled to begin in February and an initial June 2022 operational date is now December 2022.

Hawaiian Electric said the battery project can be delayed to the end of 2022 without materially affecting grid reliability, but after that things would start to get more dicey.

The utility said in its PUC filing that a delay past the end of 2022 and up to mid-2023 would be “more problematic” because avoiding the occasional need to take oil-fired generators offline won’t be practical. In this scenario, additional contingency plans could be necessary, such as adding a 20-megawatt battery to an existing West Loch solar farm.

Extra efforts

One initiative the utility recently unveiled to provide extra power capacity after the coal plant is retired will pay homeowners a subsidy for adding batteries to rooftop solar systems.

Hawaiian Electric announced this “Battery Bonus” program in July, under which it could draw power during peak evening demand from up to 50 megawatts of batteries. However, building permit delays are hampering significant use of this program so far.

Another planned power capacity boost approved by the PUC in August will involve Hawaiian Electric seeking a partner to link up to 60 megawatts of rooftop solar system batteries to the grid so they can accept and distribute power whenever needed.

Hawaiian Electric officials regard the rooftop solar battery initiatives as important for reaching a 100% renewable energy goal but not necessary to avoid any shortfall when the coal power plant is retired.

“Lights are going to stay on,” Seu said in an interview.

Richard Rocheleau, director of the Hawaii Natural Energy Institute, agrees that the utility’s existing capacity cushion should be sufficient in 2022, but perhaps not in 2023.

The research institute, which is part of the University of Hawaii, has produced computer models based on inputs that include probabilities for utility power plant outages and sun and wind strength variability to produce a risk analysis of sufficient power after the coal plant’s retirement.

“Between the amount of solar that still looks to be on target for development and the utility’s modification of their planned (oil-fired power plant) maintenance schedule, the fall of 2022 does not look to be a serious risk in terms of capacity reliability,” Rocheleau told the joint Senate committee last month.

“We need to take a closer look at what might happen in the fall of 2023 and beyond, depending on what the utility’s flexibility in their planned maintenance is, and if there are substantially longer delays,” he added. “Essentially, we’re two years out probably to where that is a potential crisis, if it’s a crisis.”