A half century ago, the Tennessee Valley Authority generated most of its power from underground mines. Now, the utility is looking up as it considers plans to convert several coal plant sites into solar farms.
TVA released a preliminary study of the Shawnee Fossil Plant near Paducah, Kentucky, last week that suggests the federal utility could use nearly 309 acres of a covered coal ash area at the Shawnee plant for a solar farm to generate up to 100 megawatts of electricity.
"This proposed solar energy production facility would enhance TVA resources while helping meet energy production needs and meeting potential regulatory requirements," TVA said in a 79-page draft environmental assessment of the proposal.
In November, TVA directors authorized spending $216 million for the nation's first-of-its-kind pilot program to determine if closed coal ash sites are suitable for utility-scale solar projects. TVA has studied using the coal ash storage site at Shawnee and, if successful, TVA Chief Operating Officer Don Moul has said other TVA coal plants and coal ash sites might also be developed with solar arrays.
The initial environmental assessment of the Shawnee site concluded that installing solar panels atop the former coal ash ponds "would enhance TVA resources by helping to meet energy production needs and providing cost effective renewable energy." The study said the solar array and accompanying power generators and transmission lines "would not be a major federal action significantly affecting the environment" and should not require a full environmental impact study and statement.
But TVA is inviting public comments about its proposed solar project, which is known as "Project Phoenix" in reference to the immortal bird associated with the sun in Greek mythology that rises from the ashes of its predecessor.
The TVA project will cap the coal ash residue with a turf closure system and then attach the solar panels to mounting mechanisms without penetrating the liner installed over the coal ash residues, Moul said.
"I would think within two years, maybe sooner, we could have this system online (at Shawnee)," Moul told TVA directors last November. "This allows us to alleviate some of the land constraint challenges that we've had from so many of our stakeholders about utility-scale solar projects."
Solar farms typically take about 10 acres for every megawatt of power generation from the solar panels. TVA has set a goal of ultimately building or buying 10,000 megawatts of solar generation, so building all utility-scale solar could require as much as 100,000 acres for solar panels across TVA's seven-state region.
By 2035, TVA also plans to phase out the last of the 59 coal-fired generators it once operated.
Moul said up to 1,000 megawatts of such solar generation might be built at current and former TVA coal facilities.