In a statement issued March 1, the environmental group said 142 US coal-fired power plants had closed during its campaign, representing 53,978 megawatts of electrical capacity.

Sierra Club executive director Michael Brune said the Beyond Coal campaign was clearing the path for renewable energy.

“Just a year-and-a-half ago, I stood beside Mayor Bloomberg with the coal-fired Potomac Generating Station as a backdrop, and together we pledged to move our nation beyond coal,” he said.

“Today that coal plant is closed, more than one-sixth of the nation’s coal capacity is slated for retirement, and wind and solar are growing faster than any other energy source.

“While Congress is paralysed by partisan bickering, our grassroots, people-powered campaign is succeeding city by city and state by state, helping the US lead the world in cutting dangerous carbon emissions.”

American Electric Power last week signed an agreement with the US Environmental Protection Agency to stop burning coal by 2015 at three power plants in Indiana, Ohio and Kentucky.

Collectively, a total of 2011 megawatts of coal-fired power will be retired as part of the deal.

AEP will stop burning coal at the Tanners Creek generating station unit 4 in Indiana, the Muskingum River power plant unit 5 in Ohio and the Big Sandy power plant unit 2 in Kentucky.

Under the suit AEP also agreed to install pollution-curbing dry sorbent injection technology on its Rockport coal-fired power plant in Southern Indiana.

The company must either retire the two Rockport units in 2025 and 2028 respectively, or install additional controls designed to achieve removal of at least 98% of the sulfur dioxide created at those units.

Additionally, the agreement commits AEP to developing 50MW of wind or solar power this year and an additional 150MW of wind or solar power in Indiana or Michigan by 2015.