A sign at the Maine Turnpike rest stop in West Gardiner points out the electric vehicle charging station. Credit: Jessica Piper / BDN

WEST GARDINER, Maine — A regular gallon of gasoline was still priced at $4.14 at the Maine Turnpike rest stop in West Gardiner on Saturday.

But while dozens of cars pulled through the Citgo station over a few hours, the nearby electric vehicle charging station sat empty.

High gas prices in recent months have further highlighted the appeal of electric vehicles, which had already seen growing demand in Maine for several years. With the transportation sector accounting for more than half of greenhouse gas emissions here, broad adoption of electric vehicles is also central to the state’s climate goals.

Under Gov. Janet Mills, the state has set ambitious targets including having 219,000 electric passenger vehicles on the road by 2030 as part of an effort to reduce emissions 45 percent. Electric vehicle sales have shot up in recent years as the state has upped financial incentives and installed charging infrastructure.

But recent global supply chain problems have also forced Mainers into long waits for both plug-in hybrid and battery-electric cars, as well as traditional gas-powered vehicles. That is an annoyance for customers, but also poses a broader challenge as the state looks to increase the number of electric vehicles on the road here sixfold in the next few years.

“We’re in a really interesting and challenging dilemma in that we have these very aggressive EV and climate goals, and we have inflation and high gas prices, which would normally make EVs very attractive,” said Jeff Marks, senior policy advocate at the Acadia Center, an environmental nonprofit. “But then you have these supply inventory issues that are really holding things back.”

The number of electric vehicles registered in Maine more than doubled from 2018 to 2021, state data show. But the current total, around 6,000 cars, is still a far cry from the state’s 2025 goal of having 41,000 such cars on the road.

Electric vehicle purchases in Maine rose rapidly in the first half of 2021, accounting for roughly 3.7 percent of new passenger vehicle sales from January through June, up from 1.5 percent in 2020. But sales slowed in the second half of the year due to decreased inventory.

“There aren’t enough cars,” said Adam Lee, chairman of the board at Lee Auto Malls who is himself an electric vehicle owner.  “It doesn’t matter how many people want to buy them if we can’t supply the cars.”

The problem isn’t unique to Maine. Global demand for electric vehicles has driven up the costs of key minerals, such as nickel and lithium. President Joe Biden invoked a federal law month to boost domestic production of minerals needed for vehicle batteries, but the effects of that order will take time.

When the supply chain issues are resolved is “anybody’s guess,” said Molly Siegel, program director for Efficiency Maine, the quasi-state agency that oversees programs aimed at reducing greenhouse gas emissions.

“It’s very complicated, because the supply chain includes battery materials, minerals [and] chips, so it’s really hard to say when that will let up,” Siegel said. “It will eventually let up, but we don’t know if that’s going to be six months, or a year, or two years.”

While supply chain challenges are largely out of the state’s control, Efficiency Maine has been working to install charging stations on key travel corridors and offering grants to help businesses, municipalities and multi-family dwelling units set up charging stations. On Friday, Mills announced that Bangor will receive $50,000 to install additional public charging stations as part of a smattering of Earth Day grants to municipalities.

Efficiency Maine also offers rebates for purchases of new electric vehicles, reducing vehicle costs by up to $2,000 for most consumers, $5,500 for low-income families and $7,500 for municipalities and nonprofits.

Although supply chain issues may mute the short-term effect of these programs on electric vehicle sales, the greater charging availability could make electric vehicle adoption easier for consumers down the line. Such programs also aim to make access to electric vehicles more equitable.

Electric vehicle purchases have largely been concentrated in wealthier parts of the state. Among municipalities with at least 1,000 people, the towns of Cape Elizabeth and Cumberland had the highest concentration of electric vehicles as of 2020, state data show.

Helping low- and middle-income Mainers install home charging systems will be key to broader electric vehicle adoption, said Jonathan Rubin, an economics professor at the University of Maine whose research focuses on energy and transportation issues. He noted that Maine generally has an old housing stock, with many homes not equipped for rapid charging.

Improving access to electric vehicles for Mainers in other parts of the state would also help with the state’s climate goals, because rural residents are even less likely to have access to public transportation, he noted.

Rubin got a battery electric vehicle of his own, a Volkswagen ID.4, a few months ago. It shipped from Germany eight months after he had ordered it.

“We’re making good progress,” he said. “But to get 200,000 vehicles in eight years is a big challenge.”