TVA officials are currently conducting a study on solar panels at Tims Ford Dam to determine the effectiveness of using river water to cool the panels while still collecting sunlight.
This is in addition to the utility’s recent “health checks” at the Franklin County dam and elsewhere.
Two large grids with 10 panels each are currently installed side by side, just below the dam. The panels on the left receive no water, while those on the right side receive a constant flow of cool river water across their surface.
According to Neil Placer, senior analyst, and Patty West, director of TVA’s Renewable Energy Program, one of the drawbacks of solar power is that the panels can get overheated, resulting in reduced output and efficiency.
“On very hot days, the panels can get up to about 175 degrees Fahrenheit,” Placer said. “These are like low-cooking temperatures, and they can reduce the panel’s performance.
“But river water stays about 50 degrees year round, and since it’s plentiful at the dam, we felt it was a good place to study it.”
According to communications partner Scott Brooks, the study is intended to collect a year’s worth of data.
“We hope to see a 35 percent energy boost during peak (sunlight) periods in August and September for the water-cooled panels,” Placer said, “and we’re hoping for an average annual boost of roughly 15 percent.”
While Tennessee has fewer sunny days than southwestern states like New Mexico and Arizona, where the dry climate results in minimal clouds and rain, West said Tennessee is currently ranked number two in its southeast operational area next to North Carolina for installed solar operations and is on track to receive several more in the future.
A recent TVA press release states that the Solar Energy Industries Association ranks Tennessee seventh in the nation for total solar capacity in 2013 and ninth in the nation for non-residential capacity.
It also states that, since the year 2000, the number of operating installations in the overall Tennessee Valley area has grown from three to 1,695, including at 91 schools, with more expected next year.
“In 2014,” West said, “we’re offering 126 megawatts of renewable energy through programs for developers and consumers who want to supply their own solar power, as well as programs for larger commercial customers and utilities.
“Local programs for solar installation will be implemented by local power distributors, such as TUB in Tullahoma, so interested parties should call them.”
West added that she is a former graduate of Tullahoma High School herself who became fascinated with science and now holds a Bachelor of Science in chemistry and a master’s degree in civil engineering from Tennessee Tech.
“My maiden name is Baird, and Jane Weaver was one of my favorite science teachers,” West said, adding that she is now in her “dream job” after many years with TVA.
She and Placer added that, with the increasing number of installations as well as increases in efficiency, the price of solar power has dropped dramatically in recent years.
“Back in the 1970’s, the price of solar was around $200 per watt,” Placer said, “but now it’s as low as $2 – $4 per watt, depending on the size and scale of the installations and other factors.”
West added that the price of solar power has also dropped roughly 40 percent in just the last two years, largely due to the increase in installations, and that total renewable energy sources for TVA stand at 16 percent, including hydroelectric power, which TVA also considers renewable.
“One drawback of solar,” Placer said, “is that it’s an intermittent source, it’s not around-the-clock, and it’s also less controllable than hydroelectric (power), so if you install your own solar panels, you have to have some type of backup or be connected to the energy grid to maintain your power flow.”
West then explained that while TVA is expanding its use of solar energy, the best source for the consumer is a diversified mixture of different types of energy, so that if one type experiences a shortage or other problem, other sources can take their place.
“You never want to put all your eggs in one basket,” West said, “so TVA intends to maintain a diversified mixture of nuclear, coal, gas, hydroelectric and solar to have the most efficient and reliable source of power for the consumer.”
She added that TVA is currently developing an Integrated Resource Plan (IRP) to determine its mixture of power generation sources in the future and will be soliciting input from the public.
According to the IRP page at www.TVA.gov, the purpose of the IRP is to identify the portfolio most likely to help TVA lead the region and the nation toward a cleaner and more secure energy future, relying more on nuclear power and energy efficiency and relying less on coal.
—By Marian Galbraith, Tullahoma News Staff Writer