The Tennessee Valley Authority is planning to build a utility-scale solar farm on top of a coal ash landfill in far western Kentucky.
The $216 million pilot initiative at the Shawnee Fossil coal-fired power plant in West Paducah would produce 100 megawatts of power on a 309-acre solar farm. Solar advocates say that’s enough electricity to power roughly 10,000 homes.
The TVA said in a November release that this is just one of multiple "intentional actions'' the agency is taking towards decarbonization, including projects related to renewable energy, hydrogen, electric vehicles, energy storage and nuclear power.
The TVA plans to add 10,000 megawatts of solar power to its system by 2035 and has put out requests for proposals for up to 5,000 megawatts of carbon-free energy before 2029.
The agency announced last year that it plans to retire all of its coal fired power plants by 2035 and replace some of them with natural gas plants – an effort which would still fall short of the goal set by President Joe Biden’s administration for a carbon pollution-free energy sector.
“The space between execution and aspiration is where innovation lives,” TVA president and CEO Jeff Lyash said in a release. “Achieving a net-zero clean energy future is critical to our nation’s energy security goals and requires innovative thinking and exploring new technologies. TVA was created as an innovation company and is uniquely positioned to demonstrate these technologies for the rest of the industry – both in the U.S. and around the world.”
Power plants store coal ash – the toxic byproduct of coal-fired power generation – in massive ponds and landfills nearby that often leak hazardous levels of pollution into the environment.
By placing a solar farm on top of a coal ash landfill, the project would be able to utilize existing transmission infrastructure already in place at the plant, and find use for a brownfield site – a property where development is complicated by the presence or potential presence of hazardous substances.
These developments come as a U.S. government tracking system projects renewable sources, including wind, solar and hydroelectric power, will generate 22% of the country’s electricity by the end of the year – more than coal at 20% and nuclear at 19%.
TVA spokesperson Scott Fiedler said if the project in West Paducah is successful, the agency would consider building solar farms at the company’s four other active coal fired power plants, as part of an effort it’s calling Project Phoenix. He said that could produce up to 1,000 megawatts of solar energy.
“We don't have a good use for these facilities because they've got to stay as they are – encapsulated in perpetuity,” Fiedler said. “So by finding new ways to use this site, we get two benefits: we've got the solar benefit, and we get a reuse benefit from it.”
Solar proponents have expressed support for the project, while some environmental advocates are concerned about the potential for it to worsen groundwater pollution from the coal ash field.
Andy McDonald, a clean energy advocate with the Kentucky Solar Energy Society and consulting firm Apogee, said more solar power is a good thing.
“I think it sounds like an exciting thing for TVA to be exploring the prospect of putting a large amount of solar on closed coal ash storage sites. We need to build out a vast amount of solar energy,” McDonald said. “The nation seems to be on that path and the more we can use brownfield sites, like coal ash sites, the better.
McDonald said there are currently more than 30 large-scale solar projects in development in Kentucky. The TVA pilot project comes with the development of multiple solar projects in western Kentucky, including BrightNight’s planned 125-megawatt solar farm in McCracken County.
Data published by the TVA shows groundwater collected from wells at the Shawnee Fossil Plant site has been contaminated by molybdenum. A report from Earthjustice, a nonprofit public interest environmental law organization, indicates that TVA data shows unhealthy levels of boron.
Earthjustice senior counsel Lisa Evans said the project is a positive development for renewable energy, but the group is hopeful that any issues surrounding contamination can be resolved.
“We would genuinely be supportive of the installation of more solar power and retiring coal plants. We also feel that there needs to be transparency in how this is done, with plans for the maintenance and construction of the installations be released ahead of construction to the public and to regulators, and also plans for how they will continue to monitor and maintain that coal ash landfill for decades after the installation is completed,” Evans said. “Coal ash is a dangerous contaminant that's going to have the potential to continue to contaminate groundwater long after landfills are closed.”
Recent Earthjustice reports that rely on data from utilities found a western Tennessee coal ash landfill was among the 10 most contaminated sites in the U.S. and at least six Kentucky utilities have long-term plans to store coal ash in unlined storage ponds.
Evans said she’s concerned construction of the solar farm will strain the cap of the coal ash landfill, and repairs will be difficult once it’s in place. She said it’s “absolutely essential” that the agency restores groundwater and makes sure the landfill’s impermeable cap is secure.
“It's essential that that cap not allow any water to enter that landfill,” Evans said. “When water soaks coal ash in a landfill, the coal ash contaminants – very harmful contaminants like arsenic in this case, molybdenum and lithium – have been leaking from the landfill.”
Putting solar installations on brownfield sites and landfills isn’t uncommon. The U.S. Environmental Protection Agency and the National Renewable Energy Laboratory jointly released a best practices guide for how to ensure solar energy systems don’t compromise the caps that seal landfills.
In a statement provided to WKMS, an EPA representative said utility-scale solar systems can be placed on coal ash landfills without endangering the environment.
“The most important consideration in the design and installation of a PV (photovoltaic) system on a coal ash landfill is that it be done in consultation with federal, state and local authorities and comply with applicable laws and regulations and closure, stormwater runoff, and other permitting requirements,” the statement said. “This will ensure that the PV solar design and installation appropriately considers and mitigates inherent risks.”
The Rock River Solar Plant in Wisconsin and the Orlando Utility Commission’s Community Solar Plant in Florida have executed similar efforts in the last decade. Both projects sit atop coal ash landfills and anchor the solar arrays using ballasted systems to try and minimize impacts on the landfill cap.
TVA chief operating officer Bob Moul said the utility will use a “closure turf” system to cap the coal ash field during November’s board meeting, but made no mention of what sort of structure would be used for the solar arrays.
TVA spokesperson Scott Fiedler said the project is “closer to the starting line than we are to the finish line.”
“We've got to go through the environmental reviews and then any type of regulatory approvals, then it will move into more of a planning phase and that allows us to really dive into those numbers and figure out where this money's going but the key is that we've got the money approved we're moving forward with the project and we're bringing new life to a coal facility that you know would have just sat dormant there with an ash stack,” Fiedler said.
Moul said the project, pending environmental and regulatory reviews, could be operational in two years.
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