Brayton Point Power Station in Somerset, the constant target of protesters who decried it as the region's worst air polluter, will shut down as of May, 2017.

That announcement came Monday from Curt Morgan, president and CEO of Brayton Point Energy LLC, the company that recently purchased the coal-fired facility. The firm purchased the power plant several months ago from Dominion to Energy Capital Partners with the stated intent of eventually converting it to natural gas.

In their statement, the power station's owners cited low electricity prices, abundant natural gas, and looming costs "to meet environmental regulations and to operate and maintain an aging plant." The firm said it will continue to supply power to the grid until its closing.

Brayton Point employs just under 250 people in Somerset and surrounding towns.

"We understand the impacts that this decision … will have on the employees of Brayton Point, the local community and other stakeholders," Mr. Morgan said, adding that they will do their best to ease the transition.

"I'll believe it when I see it," said Rep. Ray Gallison (Portsmouth/Bristol) of the announcement.

He said the 2017 date leaves "too much time for something else to happen … a lesson learned in the LNG fight." Brayton Point's electric rate permit could be re-set in May, 2016 "and a lot can happen between now and then." He said that the town of Somerset likely won't take the loss of jobs and a $16 million payment in lieu of taxes lying down. And the Federal Energy Regulatory Commission might step in if it felt adequate power supply to be at risk.

"It's great news but I'll believe it when I see the lights turned off and the doors locked. Given what they have spent, I can't see them just walking away."

Senator Walter Felag (Warren/Tiverton/Bristol) said, "This is truly a victory for the local environmental area, both in the air quality and the Mt Hope Bay ecosystem. Coal-fired power facilities are obsolete and need to be replaced."

State Rep Jay Edwards of Tiverton said, "I's a great day did the air in Rhode Island. Brayton Point is the single biggest polluter of the East Bay and the Ocean State so I am glad to see it closing."

No sooner had the announcement been made than press releases began flying from environmental groups that have staged numerous protests there, the most memorable of which involved anchoring a fishing boat in the path of an incoming coal ship. Groups had been predicting such an outcome as the power plant posted dire earnings predictions — $3 million in losses were forecast for next year.

“Brayton Point is the largest and most modern coal-fired power plant in New England. If they can’t make a go of it, none of them can … This is a death knell for coal in the region," said Jonathan Peress, vice president of the Clean Energy and Climate Program for the Conservation Law Foundation. "It's a very clear indication that coal-fired power is no longer economically viable."

“Now the hard work begins in transitioning this former coal community towards a 21st century innovation economy. We will continue to work alongside community members for resources to move Somerset into a healthy and thriving future," said  Clean Water Action Massachusetts.

“Families in Massachusetts and Rhode Island will breathe easier when this plant is no longer belching harmful pollution into the air. It’s critical that ECP and our state’s leaders work to ensure a responsible transition plan that cares for the community and workers that will be affected when the plant retires," said James McCaffrey of the Sierra Club of New England.

The shutdown announcement comes not long after Dominion spent over $1 billion to upgrade the plant. Two mammoth cooling towers, the tallest structures around and visible from Massachusetts and East Bay towns, were built to reduce water discharge temperatures into Mount Hope Bay that were blamed for killing off fish and other creatures. Air 'scrubbing' equipment was added to reduce pollution levels that the Environmental Protection Agency called the worst in New England. And some oil and natural gas were added to the fuel mix.

According to published reports, coal accounts for about 3 percent of electricity produced in the region compared to 52 percent for natural gas. Nationwide, however, coal provided almost 45 percent of power produced in 2010, according to the U.S. Energy Information Administration.