Massachusetts’ highest court on Tuesday resoundingly upheld the state’s power to impose limits on carbon emissions from power plants.

It’s the latest example of states establishing their authority to fill the regulatory void the Trump administration is creating as it moves to roll back the Clean Power Plan and other federal climate regulations.

The Massachusetts Department of Environmental Protection finalized rules last year to require power plants within the state’s borders to reduce their emissions annually, amounting to a 7 percent reduction in greenhouse gas emissions from current levels by 2020 and an 80 percent reduction by 2050. It is one of a suite of clean energy and pollution control policies state officials have put into place under the Global Warming Solutions Act, signed into law by then-Gov. Deval Patrick in 2008.

The law’s “name bespeaks its ambitions,” Justice Scott Kafker wrote for the unanimous seven-member Massachusetts Supreme Judicial Court. It “was passed to address the grave threats that climate change poses to the health, economy, and natural resources of the Commonwealth.”

“The act is designed to make Massachusetts a national, and even international, leader in the efforts to reduce the greenhouse gas emissions that cause climate change,” he wrote. Since the electric power sector is one of the largest sources of greenhouse gas emissions within the state, Kafker, who was appointed last year by Republican Gov. Charlie Baker, said, it would make “little to no sense” for the Legislature to have excluded it from the requirements of the law.

The court dismissed the arguments of the electric power industry (represented by the New England Power Generators Association and GenOn Energy) that the sector is subject to other state regulations and therefore can’t be subject to the carbon emissions rules. Kafker said the environmental regulations don’t conflict, but complement each other.

He also brushed aside the industry’s contention that the new rules could have the unintended consequence of increasing carbon emissions if Massachusetts seeks additional power from out of state that ends up being dirtier. Kafker noted that the state has a renewable energy standard in place that is designed to force power providers to rely on an increasing amount of clean energy.

“Far from causing increased greenhouse gas emissions from out-of-State generators,” Kafker wrote, state environmental officials had provided convincing evidence that “the two regulations together will send a market signal that Massachusetts’ neighbors should invest in clean energy development in order to satisfy the Commonwealth’s increasing demand for renewable energy.”

Massachusetts’ Push Away from Fossil Fuels

The decision comes at  pivotal moment for Massachusetts, as it transitions to cleaner energy.

The state’s last coal plant, Brayton Point in Somerset, closed last year, and the state has been investing in the infrastructure to support an offshore wind industry. The Vineyard Wind project, an 800 megawatt offshore wind farm planned off the coast of Martha’s Vineyard, is expected to soon start the state toward its goal of having 1,600 megawatts of offshore wind energy by 2027.

“It spells the end of fossil fuel electricity in Massachusetts,” said David Ismay, an attorney with the Boston-based Conservation Law Foundation, arguing the standards will mean a gradual phase-down in the natural gas generation, which dominates the state’s electricity mix.

“It solidifies the shift to clean energy.”

States Leading the Way Toward Cleaner Energy

The Massachusetts plan to reduce carbon emissions from power plants is just one example of states seizing the initiative to force reductions in greenhouse gases over the past year as President Donald Trump has made clear his intention to abandon the U.S. commitment to reduce emissions. California lawmakers last week voted to require that state’s utilities to use 100 percent carbon-free power by 2050. Hawaii has a similar requirement. Other states have increased their renewable portfolio standards for clean energy.

Massachusetts is also part of the nine-state Regional Greenhouse Gas Initiative, which last year updated its cap-and-trade program to achieve a 30 percent reduction in carbon pollution from the region’s power plants by 2030. (In 2016, the Massachusetts high court said that state officials could not rely on RGGI alone to achieve the goals of the state’s Global Warming Solutions Act, since it did not guarantee Massachusetts-based emissions reductions. The rules upheld on Tuesday were written in response to that ruling.)

Governors of a dozen states have committed to reduce emissions in line with the U.S. goals under the Paris Agreement even though Trump has announced his intention to withdraw. The climate action commitments made by states, cities and businesses will be the focus of a Global Climate Action Summit scheduled for next week in San Francisco.

Ismay said he believed the Massachusetts court decision will resonate beyond the state.

“We can’t solve it alone,” he said. “But we can have an impact by pointing a way forward, and passing strong laws that are upheld.”