SALEM, Mass. – The Rev. Jeff Barz-Snell is looking forward to this Sunday. Fifteen years of labor, strife and community organizing is about to pay off.

The Salem Harbor Power Station, a hulking 720-megawatt coal- and oil-fired plant that dominates the waterfront in this historic New England town, goes dark on June 1. Having generated power since 1951, Salem Station succumbed to low natural gas prices, weak electricity demand growth and tightening Federal pollution controls.

"No one drives a 30-year-old car, so why should we rely on 60-year-old power plants?" said Barz-Snell, a Unitarian minister, Salem resident and co-chair of the Salem Alliance for the Environment, or SAFE. He's been fighting to close the plant since 1999. "It's insane to have a dirty coal plant in a densely-populated area."

The plant's new owner, Footprint Power, will demolish the coal plant, clean the 65-acre site, then build an advanced 674-megawatt gas plant that has one-third the footprint. The remaining 47 acres, if all goes as planned, will be redeveloped, with some of the land saved to eventually support the construction and operation of offshore wind farms.

Several hundred coal-fired power plants will close nationwide by 2020, according to the Department of Energy's latest forecast. It’s a process that may well accelerate under the Obama administration’s new proposed carbon pollution regulations for existing coal power plants, to be unveiled June 2.

Most closures will be in the mid-Atlantic, Southeast, and Midwest, where coal generation is concentrated. As communities consider life after coal, many will struggle to balance competing priorities – jobs, tax revenues, clean air, greener power, profitable development. Some will be left with abandoned plants and sites contaminated with ash and sludge that contains arsenic, lead and other toxic heavy metals.

"The impact is like losing a large factory or a military base," said Seth Kaplan, vice president for policy and climate advocacy at CLF. "We're not good at managing these kinds of transitions in a market economy."

Shuttered power plants can become white elephants. Some have sat abandoned in cities like Philadelphia, New Orleans, and Yonkers, N.Y., for 20 years or more, their slow decay chronicled online by "ruin porn" photographers.

Salem, unlike other towns in its situation, has a developer ready to clean the site up and put something new there. So Footprint's plan may seem like good news.

But Footprint's proposal was only approved in February after several years of debate, culminating in a legal settlement between Footprint and the Conservation Law Foundation, the largest environmental advocacy group in New England. The CLF argued that adding more fossil fuel generation – even an efficient gas-fired plant – would prevent Massachusetts from cutting its carbon dioxide emissions 80 percent by the year 2050, as state law requires.

Salem Station became a target in the late 1990s, when environmental, health and civic groups launched a campaign to force Massachusetts to clean up what they called the "Filthy Five" – a group of coal-and oil-fired power plants built before 1977 and grandfathered under the Clean Air Act from meeting new air pollution standards. In 2000 researchers at the Harvard School of Public Health estimated that emissions from Salem Station caused 53 premature deaths, 16 heart attacks, more than 14,000 asthma attacks and 570 emergency room visits yearly. Then-Gov. Mitt Romney held a press conference in Salem in 2003 and declared, "that plant kills people."

In 2010 environmental groups sued Salem Station's owner, Dominion Energy. To settle, Dominion retired two of the plant's four burners in 2011 and agreed to close the rest by 2014. Activists hailed the news, but city leaders worried about lost property taxes – $4.75 million in a city budget of $130 million – and cleanup costs. "Environmentalists said there was no way the plant could stay open, and business interests said there was no way it could close. And in a sense they all were right," said Salem Mayor Kim Driscoll.

Peter Furniss and Scott Silverstein, two power industry veterans, saw opportunity. They had formed Footprint Power in 2009 to develop new, cleaner generation at coal plant sites. Salem was an ideal test case: an old, dirty plant in a region already shifting from coal and oil to natural gas. Footprint, self-financed with contributions from its partners, bought the plant in 2012 and pledged to pay the same yearly property taxes and fees while they built an advanced quick-start gas-fired plant.

Many activists pushed back, arguing for wind or solar generation or non-energy uses, such as a marine biotechnology research facility.

For the mayor and many Salem residents, Footprint's proposal offered a compromise that maintained jobs and a tax base while freeing up waterfront acreage for other uses. "It's hard to find reuse options that will cover the costs of a multi-million-dollar cleanup," Driscoll said. "And there are many examples of corporations closing plants and leaving them there, so we saw this as a good transition."

The February agreement between Footprint and the Conservation Law Foundation let the gas plant go forward. It put a declining cap on the plant's CO2 emissions and required Footprint to shut it down by 2050. Footprint promised the plant wouldn't bust Massachusetts' greenhouse gas limits, Kaplan said. "So we said 'Okay, put that in the permit.'" The agreement makes the proposed gas plant the first to be approved with an expiration date.

Coal energy's reversal of fortune over the past decade has been dizzying. Its share of U.S. electricity generation fell from 52 percent in 2000 to 37 percent in 2012, thanks to a boom in shale gas development. The Energy Information Administration projects that by 2035 natural gas will generate more electricity than coal.

As gas eats into coal plants' profit margins, new limits on mercury and air toxics emissions taking effect in 2015 will take another bite. Another measure, the federal Cross-State Air Pollution Rule, will require still more expensive controls on coal plants in the Midwest and South to reduce sulfur dioxide and nitrogen oxide emissions that travel across state lines, creating ozone and fine particle pollution downwind.

Many companies are instead shutting plants down.

Is gas the answer? Footprint's owners contend that the gas plant will make Salem a healthier place to live. Many minority, low-income and limited-English residents live close to the Salem plant and are at risk from its emissions. "The existing plant has outrageously high nitrogen oxide and particulate emissions, which contribute to ground-level ozone and exacerbate asthma. We think it's important to shut it down and replace it with one that will reduce pollution locally and regionally," Furniss said. He estimated that switching from coal to gas in Salem will cut New England's sulfur dioxide emissions by 10 percent, nitrogen oxide by 8 percent, and mercury by 6 percent, and will reduce the region's carbon dioxide emissions by about 450,000 tons per year.

Martha Dansdill, the director of HealthLink, an activist group based in nearby Swampscott, is unpersuaded. Dansdill has marshaled opposition to running a gas line to the new plant through densely populated neighborhoods. The state, HealthLink argues, should help Salem find other uses for the site. Another group, GASPP, or Grassroots Against Another Salem Power Plant, has pledged to use peaceful civil disobedience to block construction of the gas plant.

In contrast, SAFE conditionally supports the gas plant. "We have to build a mind-boggling amount of infrastructure to scale up renewables, and it won't happen overnight," Barz-Snell said. "In the meantime, this plant will provide the cleanest and most efficient generation in Massachusetts."

Some communities might welcome a developer like Footprint, but for now the company is focused on Salem. And Furniss acknowledges that its approach is not very scalable. "Building a power plant is very people-intensive," he said. "I'd like to see us managing a couple of projects at a time, but I don't envision growing beyond that level."

Massachusetts activists, meanwhile, are focusing on Somerset, 60 miles south of Salem, which has two old coal plants. The smaller plant, Somerset Station, shut down in 2010 and stood vacant while the owner stripped it for scrap and then went bankrupt, leaving unpaid tax bills. Somerset's other plant, Brayton Point, is twice as large as Salem Station and is still burning coal, but the 1,500-megawatt plant is scheduled to shut down in 2017. Residents have criticized local officials for failing to identify new development opportunities or alternative uses for the plants. Massachusetts has offered $6 million to Somerset, Salem and Holyoke, site of a third aging coal plant, to pursue renewable energy projects, but state officials say decisions about the future are up to communities.

"Towns need to be realistic about the future of coal plants. Assuming they will always be there inhibits rational planning," said Kaplan, the CLF vice president. "Officials should acknowledge the risk that plants will close and start diversifying their commercial tax bases to prepare for it."

"Getting these decisions right is hard, but it's especially hard for places that have an emotional attachment to coal.",

This article originally appeared at The Daily Climate, the climate change news source published by Environmental Health Sciences, a nonprofit media company.