A coalition of nine states from Maryland to Maine on Wednesday announced an aggressive plan to cut power plant emissions in the next decade, one of the broadest efforts to address climate change since President Trump said the United States would withdraw from the Paris accord.
After more than a year of negotiations, states in the Regional Greenhouse Gas Initiative, a market-based effort considered a model for curbing emissions, agreed to reduce power plant emissions by another 30 percent from 2020 to 2030.
The plan, which must be approved by each state, including Massachusetts, would lower these emissions by more than 65 percent since 2009, when the states began setting annual caps.
“This is a very dramatic, significant carbon reduction,” said Katie Dykes, a public utilities regulator in Connecticut who serves as chair of the coalition’s board of directors.
The agreement calls for steady yearly reductions in Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New York, Rhode Island, and Vermont.
Under the program, known as cap-and-trade, power plants buy pollution permits at auctions several times a year. Those permits, or allowances, can be traded between companies based on how much carbon dioxide they release. Over time, the caps on the allowances have been lowered, making the permits more expensive and providing incentives for companies to use cleaner energy.
Proceeds from auctions support energy efficiency programs. Since the initiative began in 2008, for example, Massachusetts has earned about $440 million from the auctions.
“We’ve demonstrated . . . we’re creating a broader market that’s sending a strong investment signal across the Northeast to drive our transition to a clean energy economy,” Dykes said.
While environmental advocates had urged the states to go even further in cutting pollution, many praised the deal.
“This is what climate leadership looks like,” said Peter Shattuck, director of the Acadia Center in Massachusetts. “Despite the misguided and irresponsible decision to pull the US out of the Paris agreement, states and regions continue to lead, and these improvements put Massachusetts and other RGGI states in the vanguard of climate action.”
Representatives of New England’s power companies said the deal would have little impact on consumer prices, given that most of the region’s dirtiest coal and oil plants have closed. There are about 350 power plants in the region, including at least 150 in Massachusetts.
“Market-based programs provide the most efficient, competitive, and lowest-risk way to meet state mandates to address climate change,” said Dan Dolan, president of the New England Power Generators Association. “Power plants across New England have cut their C02 emissions by more than 40 percent since 1990, and are prepared to continue this remarkable track record.”
But Dolan and others urged the states to expand their focus beyond power plants, noting that emissions from transportation now account for twice as much pollution. “These states should not rest on their laurels,” said Ken Kimmell, president of the Union of Concerned Scientists in Cambridge. “Transportation is now the biggest source of greenhouse gas emissions in this region, and it will take a similarly bold and regional approach to get at that problem.”
In Massachusetts, the emissions caps dovetail with sweeping regulations issued this month that set specific limits on sources of greenhouse gases. Those rules aim to cut greenhouse gas emissions 25 percent below 1990 levels by 2020, as required by state law. Officials have said the new rules could increase utility costs for ratepayers as much as 2 percent a year.
Massachusetts officials initially urged other states to cut their power plant emissions 5 percent a year. The new plan would reduce carbon emissions by a little more than 3 percent a year, though that figure varies slightly over the decade.
Martin Suuberg, commissioner of the state Department of Environmental Protection, said, “Combatting and preparing for the impacts of climate change remains a top priority.”
States such as Massachusetts can implement the plan by issuing regulations. Others may have to seek approval from their legislatures.
During the negotiations, some states resisted the more stringent caps. Maryland and Delaware, for example, receive their electricity from a separate grid that includes coal-reliant states such as West Virginia and Kentucky, which aren’t part of the regional program. Officials there have worried stricter regulations would put them at an economic disadvantage with those states, which tend to produce dirtier energy, often at lower electricity costs. That could force their power plants to close, while residents would still be exposed to harmful emissions from across states.
But on Wednesday officials from those states praised the plan. “This consensus agreement is a win for both our environment and our economy,” said Ben Grumbles, secretary of the Maryland Department of the Environment, in a statement.
Overall, the program has reduced emissions and lowered energy prices, advocates say .
In a report last year, the Acadia Center found RGGI states reduced emissions by 16 percent more than other states, while the region’s economy had grown 3.6 percent more than the rest of the country. At the same time, energy prices had fallen by an average of 3.4 percent, while electricity rates in other states rose by 7.2 percent.
Advocates also say there have been significant health benefits and savings. They cite a report by Abt Associates, a Cambridge-based consulting group, that estimated the initiative has saved as many as 830 lives, reduced more than 8,000 asthma attacks, and saved nearly $6 billion in health costs.
The pact includes new tools that could cut emissions even more. One provision would allow states to reduce their pollution allowances if some go unused, making it less likely that power companies could bank allowances for future emissions. Another would allow states to reduce their caps by as much as 10 percent a year, when the price for the allowances falls below expected levels. The costs of cutting emissions has been less than predicted since RGGI began.
“This is an important and necessary update to the program,” said Jack Clarke, director of public policy at Mass Audubon, who noted that without action, the caps would have expired by decade’s end.