A plan to create a cap-and-trade program to regulate regional tailpipe pollution could curb greenhouse gases in a dozen Northeast states, but Maine is undecided on the proposal despite its ambitious plan to cut the state’s carbon emissions.

A coalition of transportation and environmental groups released a Transportation Climate Initiative draft memorandum of understanding Tuesday to reduce transportation pollution by capping emissions, charging fuel suppliers and investing that revenue into sustainable transportation.

The program is designed for 12 Northeast and Mid-Atlantic states and Washington, D.C.

“We are at a time right now that every day the climate crisis is more urgent than ever, and in this moment the Northeast and Mid-Atlantic states are rising to the challenge with a bold and innovative plan,” Ken Kimmell, president of the Union of Concerned Scientists, said in a conference call with reporters.

“The scale of this emissions reduction plan is huge,” he said. “If it goes through it would be one of the largest emissions reductions plans we’ve seen in the U.S.”

Conservative groups opposed to the proposal have said it sets an artificial limit on carbon emissions and companies’ costs will be passed onto consumers at the pump.

In a letter to Gov. Janet Mills and Environmental Protection Commissioner Gerald Reid, the Maine Heritage Policy Center said the program would be a regressive tax on poor Mainers and a “sin tax” for the everyday activity of driving to work, school and the grocery store.

“The TCI would hurt Maine’s infrastructure, economy and the most vulnerable among us, and our involvement would have no measurable impact on the climate,” Maine Heritage Policy Center CEO Matt Gagnon said in a statement.

A REGGI MODEL

The transportation program is based on the Regional Greenhouse Gas Initiative, a 2009 agreement to cap and trade power plant carbon emissions in nine Northeast states including Maine. Since its inception, CO2 emissions from power plants fell 47 percent, according to an analysis by the Acadia Center, a clean energy research group.

From 2012 to 2017, Maine invested $54 million from program revenues in financial incentives for energy-efficiency building upgrades through the Efficiency Maine Trust.

The TCI concept is to do the same in the transportation sector, by requiring fuel suppliers to purchase allowances for reported emissions and investing that revenue in clean transportation programs. Under the most ambitious scenario, TCI would cut vehicle emissions by 25 percent by 2033.

The program could generate more than $17 billion in the first three years, of which Maine would get $400 million, according to an analysis from the Union of Concerned Scientists. States would be able to spend revenue from the program as they saw fit.

If fuel companies passed costs to consumers, it could mean an extra 5 cents to 17 cents a gallon at the pump, far below the market price volatility in the last five years, Kimmell said in the call Wednesday.

That funding would be critical for Maine to expand electric vehicle use and public transit options, and design pedestrian and bicycle-friendly towns and cities, said Sue Ely, a staff attorney at the Natural Resources Council of Maine.

“We can reinvest those revenues into solutions that can help Mainers drive less,” Ely said. “Mainers are sending $3 billion a year out of state to big oil and gas companies and none of that is being spent on transit, electrification, and bike and pedestrian pathways to transition our transportation system to one that is modern, safer and less polluting.”

Maine was a signatory to the initiative’s declaration of intent in 2010, but did not join nine states and Washington D.C. as an active participant last year.

Since then, the state has embarked on a plan to reduce greenhouse gas emissions by 80 percent by 2050. In September, Mills pledged to make Maine carbon-neutral by 2045.

Transportation accounts for 52 percent of the state’s overall carbon pollution and cutting those emissions poses the biggest obstacle to achieving the state’s goals. Maine has a weak public transit network, rural, dispersed communities and an infant electric vehicle infrastructure.

In an email, Lindsay Crete, the governor’s press secretary, said the state continues to monitor the regional transportation emission initiative but has not signed onto the agreement.

“The challenges of climate and transportation issues for rural states like Maine are unique, and the state will be appropriately cautious when considering these issues, along with our own basic transportation needs and emissions challenges,” Crete said.

She did not respond directly to questions about how the agreement might be adopted by state government.

Stakeholders have until late February to submit comments on the draft Transportation Climate Initiative memorandum of agreement. States are expected to decide whether to join the initiative by the spring of 2020. The earliest the plan would go into effect is 2022.