While Hawaiʻi is progressing to get fossil fuels out of the electrical grid, transportation is lagging behind.
The transportation sector — aviation, marine and ground transport — is the largest source of emissions in the state.
Within that category, vehicles on the road account for about 38% of transportation emissions. Gains in fuel efficiency have been largely canceled out by an increasing number of cars in Hawaiʻi.
High gas prices in 2014 and pandemic stay-at-home orders in 2020 caused slight dips in the total number of emissions from ground transport, but otherwise, levels have remained relatively constant over the last 15 years.
Hawaiʻi desperately needs to electrify transportation, according to local climate analyst Jeff Mikulina. Though electric vehicle technology has improved and incentives are available, adoption of EVs has been slow-going.
"About 3% of our cars are zero emission or electrified in Hawaiʻi," Mikulina said. "And that needs to be much higher."
Hawaiʻi lawmakers are looking at another way to clean up transportation by lowering the amount of carbon in the fuel itself.
Senate Bill 2768 would require the Hawaiʻi State Energy Office to develop a clean fuel standard that reduces the allowable carbon intensity of fuel to at least 10% below 2019 levels by 2035 and at least 50% below 2019 levels by 2045.
That can be achieved one of two ways — either by using a fuel that's less carbon-intense, like gas or diesel made from biomass, or by purchasing a credit from a clean fuel producer.
"It's a really novel, market-based, sort of technology agnostic approach," Mikulina said. "As opposed to prescribing what [the fuel] needs to be or direct incentives, it sort of lets the market figure that out."
But some experts say letting the market shape policies can be counterproductive.
Jeremy Martin is the director of fuels policy for the Union of Concerned Scientists. He said California, which is in the process of reforming its clean fuel standard, has grown over-dependent on biodiesel.
"More than half of the diesel fuel used in California now is renewable diesel, versus about 4% of the rest of the country," Martin said.
That renewable diesel is primarily made out of used cooking oil. "But the problem is that there's really not a lot of used cooking oil or vegetable oil in the world," Martin said.
The increasing demand for vegetable oil puts companies in competition with food producers, Martin said. "We don't want oil refineries competing in food markets to take away scarce vegetable oil, especially during a global food crisis."
Despite this market imbalance, Martin still thinks that fuel standards are an important tool for reducing transportation emissions, and he hopes a cap on biodiesel will get California's fuel standard back on track.
Jeff Mikulina said Hawaiʻi should take note of both California's successes and its missteps.
"One of the challenges with low carbon fuel standard is creating some market distortions that might yield outcomes that we don't want," Mikulina said.
"So the most important thing is making sure we do the math right. We don't want to trade off one environmental problem for another."
