In a twist, old coal plants help deliver renewable energy. This is how.

Across the country, aging and decommissioned coal-fired power plants are being given new life as solar, battery and other renewable energy projects, partly because they have a decades-old function that has become increasingly valuable: They are already connected to the power grid.

The kilometers of high-voltage power lines and towers that are often needed to connect power plants to customers far and wide can be costly, time-consuming and controversial to build from scratch. So solar energy and other projects avoid regulatory problems, and possibly speed up the transition to renewable energy, by connecting the unused connections that remain as coal becomes uneconomical to continue burning.

In Illinois alone, at least nine coal-fired power plants are set to become solar farms and battery storage facilities over the next three years. Similar projects are taking shape in Nevada, New Mexico, Colorado, North Dakota, Nebraska, Minnesota and Maryland. In Massachusetts and New Jersey, two retired coal-fired power plants along the coast are being reused to connect offshore wind turbines to the regional power grids.

“A good result of having had all these dirty power plants is that we now have pretty robust transmission lines in these places,” said Jack Darin, director of the Illinois branch of the Sierra Club, an environmental group. “It’s a great resource.”

Over the past two decades, more than 600 coal-burning generators with a total production capacity of around 85 gigawatts have withdrawn, according to the US Energy Information Administration. (Individual power plants may have more than one generator.) A majority of the 266 remaining coal-fired power plants in the country were built in the 1970s and 1980s, and are nearing the end of their approximately 50-year service life.

Most of the retired capacity will not be replaced by coal, as the industry is being pushed out by cheaper renewable energy and tougher emission regulations. At the same time, renewable energy producers face obstacles to getting their projects connected to the grid. Building new power lines is costly and controversial as neighbors often oppose transmission lines that could disrupt scenic views or potentially reduce property values ​​nearby. In addition, it can be time-consuming to get power line projects approved by regulators.

Construction and operation of renewable energy projects has long been cheaper than fossil fuel plants. The barrier “is no longer economics,” said Joseph Rand, a researcher at the Lawrence Berkeley National Laboratory, which conducts research on behalf of the US Department of Energy. “The hardest part is securing the pairing and transmission access.”

This makes old coal plants an attractive alternative as sites for renewable energy projects. Not only are the old plants already connected to the transmission system, they also have transformer stations that help convert electricity into a supply that is suitable for use in homes and businesses.

It was a key factor in choosing Brayton Point Power Station as a grid connection point for a 1,200-megawatt wind farm 37 miles off the coast of Massachusetts, said Michael Brown, CEO of offshore wind developer Mayflower Wind.

With 1600 megawatts, the coal power plant was the largest in New England when it retired in 2017. The plant itself, located in the port city of Somerset, will be replaced by an underwater cable factory owned by the Italian company Prysmian Group. And the offshore wind project will connect to the grid at the Brayton Point connection point, using the existing transformer station there.

In one of the most ambitious efforts, Vistra Corp., a Texas-based power generation company that also owns a number of power plants in California and Illinois, said it would spend $ 550 million to turn at least nine of its Illinois coal-fired plants into solar panel sites. and battery storage.

The largest, a plant in Baldwin, Ill., Which will retire by 2025, will have 190,000 solar panels on 500 acres of land. In total, the panels will generate 68 megawatts of electricity, enough to supply somewhere between 13,600 and 34,000 homes, depending on the season. It will also have a 9 megawatt battery, which will help distribute power when demand peaks or the sun does not shine.

Vistra’s CEO, Curtis Morgan, said it was clear that the power company would need to “leave coal behind”, and was eager to build new zero-emission projects to replace some of the power from these plants. But, he said, the slow process of getting approval from network operators, which coordinate and monitor the power supply, has been a roadblock for a number of Vista’s proposed projects.

An increase in proposals for wind, solar and battery storage projects has overwhelmed regulators in recent years, according to an analysis by the Lawrence Berkeley National Laboratory, which overlooks the University of California Berkeley campus. In 2021, waiting times almost doubled from ten years before, to almost four years, and that does not include the growing number of projects that withdraw completely from the process.

If every project that is currently awaiting approval is built, “we can reach 80 percent clean energy by 2030,” said Rand, lead author of the report. “But we would be lucky if even a quarter of what is proposed is actually completed.”

Three of Vista’s battery storage projects in Illinois – at the Havana, Joppa and Edwards coal plants – also benefited from a subsidy from a state law, the Climate and Equitable Jobs Act, aimed at supporting a “fair transition” for coal-dependent communities to renewable energy . It was signed by Governor JB Pritzker last fall, and also demanded that all fossil-burning plants cut emissions to zero by 2045, which could lead to their closure, even though most coal mines in Illinois were already ready to close. down in a decade.

The Coal-to-Solar Energy Storage Grant program that came out of the legislation also supports two other battery projects, owned by NRG Energy, which will be built at coal-fired power plants in Waukegan and Will County.

The benefit of building renewable energy projects on old coal plants is twofold, said Sylvia Garcia, director of the Illinois Department of Commerce and Economic Opportunity, which oversees the coal-to-solar program. First, projects benefit from the easy reuse of an existing network connection. Secondly, it is an attempt to “try to reinvest in the communities that have lost these coal plants” in the first place, she said.

While the new projects will temporarily create construction jobs, it usually does not require as many employees to operate a photovoltaic or battery plant. The Baldwin plant previously employed around 105 full-time workers. And while Vistra does not yet have final figures on a site-by-site basis, the nine Illinois projects will create a total of 29 full-time jobs annually, the company’s communications director, Meranda Cohn, said in an email.

Coal plants also usually sit on a significant package of land, and converting these areas into renewable energy projects is a way to put something productive on a piece of property that can otherwise go unused.

“It’s really moving a very negative resource to one that’s more positive for society,” said Jeff Bishop, CEO of Key Capture Energy, which plans to locate a 20-megawatt battery storage project at a retired coal plant near Baltimore, Md. .

Elsewhere in Holyoke, Massachusetts, the retirement of Mount Tom Station, a coal plant that had been in operation for more than five decades, provided a variety of opportunities, said Julie Vitek, vice president of government and regulatory affairs for power producer ENGIE North America. . After meetings with government officials, environmental groups and residents, a solar farm emerged as the best way to “give new life to the industrial land at Mount Tom,” she said.

Today, the property is home to around 17,000 solar panels and a small battery installation that forms a joint solar energy project managed by Holyoke Gas & Electric, a city-owned tool that gives customers the opportunity to choose to receive solar energy from the project. The panels produce about 6 megawatts of electricity, enough to power around 1,800 homes.

It is not just solar, battery and wind developers who are looking after their infrastructure on old coal plants. TerraPower, a nuclear power plant founded by Bill Gates, locates a 345-megawatt advanced nuclear reactor next to a coal plant in Kemmerer, Wyo. The location will not only allow the reactor to take advantage of the existing grid connection, but also to make use of the coal plant’s cooling system, said Chris Levesque, TerraPower president and CEO.

“In a way, it would be a shame not to use these coal plants,” Mr. Levesque said.