Jet fuel plays an outsized role in Hawaiʻi’s carbon footprint with aviation alone accounting for 46% of the state's transportation emissions.
Aside from simply flying less — a tough sell to an island state dependent on tourism with a medical system that relies on residents traveling by plane to receive critical care — the primary solution to cut carbon out of air travel could be the development of sustainable aviation fuel.
Sustainable aviation fuel, or SAF, is a catch-all term for fuels with a lower carbon intensity that can be used to power planes. Researchers are trying to make sustainable jet fuel from a range of sources including biomass, old cooking oil and even algae.
Many airlines, including Hawaiian, have made commitments to run their fleets on sustainable fuel. Virgin Atlantic ran the first transatlantic flight from London to New York with a plane powered by SAFs last fall.
Par Hawaii is converting a portion of its refinery to produce renewable fuels, including SAFs. Par President Eric Wright said that the unit should be online next year, and it will be able to replace 25% of Hawaiian Airlines' daily jet fuel demand with SAF, which will be about 40% to 50% less carbon-intensive than traditional kerosene fuel.
But green jet fuel is still a ways off from being a worthwhile investment for the state, said Hawaiʻi Deputy Chief Energy Officer Stephen Walls.
"We want to be aggressive," Walls said. "But we also want to make sure we're getting what we're paying for."
Walls said that if the state were to subsidize the production of SAF right now, it would be paying premium costs for only some carbon reductions.
"I think it would be prudent for us to let the market mature a bit," Walls said.
Wright thinks state-level incentives could help ramp up SAF production by making it more cost-effective to produce.
"It's about $2 to $4 more per gallon to make renewable fuels" rather than fossil fuels, Wright said. While federal incentives chip away at that cost, Wright hopes to see something comparable from the state in the next few years.
Ikaika Hussey said aviation is the "one missing piece" in Hawaiʻi's leadership on climate change. He's the Vice President of Development for Shake Energy Collaborative, and he's working on what he calls the "Star Trek approach" to sustainable aviation fuel — pulling carbon dioxide out of the air and then turning it into jet fuel, a process called direct air capture.
He's hoping to have a plant up and running on the islands that can manufacture carbon-neutral jet fuel by 2028. Though he's confident about his approach, he understands why state officials are hanging back when it comes to investments in sustainable aviation.
"It's a hard problem to solve," Hussey said, noting that aviation sits in a jurisdictional "gray area" between the state and the federal government.
Walls said the Hawaiʻi State Energy Office is tracking the developments in sustainable aviation fuel at both the local and global levels, and they're prepared to act when the time is right.
"Given the fiscal environment following Lahaina, I just don’t think it's this year," Walls said.
