The U.S. Environmental Protection Agency on Friday partially denied Hawaiʻi’s 2024 Regional Haze State Implementation Plan, rejecting the state’s long-term strategy to shut down at least two Hawaiian Electric Co. oil-fired generating units by 2028 while leaving some other parts of the plan in place.
The plan was meant to cut haze at Hawaiʻi Volcanoes National Park on the Big Island and Haleakalā National Park on Maui, both Class I areas under the Clean Air Act that receive the strongest federal air-quality protection. The EPA’s ruling means some of Hawaiʻi’s haze reduction efforts survive, but the agency would not accept the state’s timeline for retiring the Kanoelehua-Hill and Kahului units.
One of those plants is far older than the debate now surrounding it. The Kahului unit was commissioned in 1948, and the state’s plan called for ending operations at least two oil-fired units by 2028 as part of a wider push to improve visibility and reduce fine particulates and other man-made pollutants in the islands’ national parks.
Mike DeCaprio said Hawaiian Electric still plans to retire the aging plants, but argued that the utility needed more biofuel plants, solar farms and battery storage to come online before the end of 2028 for that to happen safely. He said the company wanted a contingency that would let the units run longer if needed.
“We felt that having a contingency to run these units longer if needed was in our interest, and in our customers’ interest, so that we don’t end up in a grid reliability issue,” DeCaprio said. He added that “reliability on an island grid is a really tough issue,” saying the systems are small and “with size comes stability, and they don’t have size.”
The EPA, in rejecting the long-term strategy, said the closures were unconsented and could make Hawaiʻi’s grid less reliable. It also said the move could violate the Takings Clause of the U.S. Constitution, which bars the taking of private property without just compensation. That is the legal edge of the decision, but the practical stakes are broader: whether the state can clean up the air above two of its best-known parks without forcing a fast transition that could strain the grid.
The ruling also lands in the middle of a larger federal shift. The decision is part of an approach under EPA Administrator Lee Zeldin tied to President Donald Trump’s executive orders promoting energy dominance. For Hawaiʻi, where some of the freshest air in the nation still gives way to hazy skies in parts of the state, the outcome touches both tourism and public health.
Isaac Moriwake of Earthjustice, which is part of a coalition of 10 national environmental advocacy groups, called the decision a major blow. “This is one of the biggest bombs to drop in Hawaiʻi so far from the EPA,” he said, warning that the ruling would harm communities and lead to dirtier air in the parks.
The immediate question now is how Hawaiʻi can keep moving toward cleaner air while protecting a grid that officials say is already fragile. Friday’s decision does not end the haze plan, but it does strip out the state’s preferred path for retiring the oil-fired units that were supposed to be part of the solution.
