America's biggest public electric utility is turning more to natural gas to generate power.
Despite opposition from some environmental groups against continuing to burn fossil fuels, the Tennessee Valley Authority is proposing to replace aging gas plants in Memphis and New Johnsonville, Tennessee, with new gas-fired combustion turbines in Kentucky and Alabama.
In a draft environmental assessment of its energy options released this week, TVA is proposing to build six new natural gas combustion turbines with a combined generating capacity of 1,500 megawatts at its former Paradise coal plant in Kentucky and its shuttered Colbert coal plant in Alabama within the next three years. Both of those plants already have natural gas-fired generators and the gas-fired peaking plants, which are designed to be used to help meet power demand peaks, will replace aging combustion turbines TVA is shutting down at its Allen plant in Memphis and its New Johnsonville plant west of Nashville.
The old plants have a combined capacity of 1,400 megawatts, but TVA's studies indicate they are less efficient and emit more carbon dioxide than the new units would.
TVA said closing the gas combustion turbines at Allen would cost eight jobs in Memphis and shutting down Johnsonville would cost 28 jobs.
"TVA would help offset this employment loss by placing some interested employees in available positions across the TVA service area," TVA said in a 301-page report on its proposed changes. "In addition to employment impacts, during the decade following the CT retirements, annual average system-wide emissions of CO2 would decrease by 0.6 percent."
TVA's power shift
The sources of TVA’s electricity generation have shifted over the past decade and a half away from coal toward more natural gas and nuclear power. Last year, TVA’s fuel mix included:* 42% from nuclear power, up from 26% in 2005* 28% from natural gas, up from 7% in 2005* 15% from coal, down from 57% in 2005* 12% from hydroelectric dams, up from 10% in 2005* 3% from solar power, up from less than 1% in 2005Source: Tennessee Valley Authority
TVA spokesman Jim Hopson said TVA is inviting comments about its plans and must still assess the financial costs of its energy options. But he said the gas-fired combustion turbines being proposed would help TVA meet power demand peaks during hot summer days or cold winter nights, especially when the sun doesn't shine or the wind doesn't blow for renewable energy generation.
"We have to look at a balanced portfolio to ensure that our future plans still ensure reliability and low-cost power," Hopson said. "So while renewables are going to become an increasing part of TVA's power portfolio, we do have to make sure that we can overcome their one significant limitation and that is that they are very intermittent in their capabilities."
But environmental groups are objecting to TVA's plans, which they claim continue to burn fossil fuels and emit carbon to generate power. The Sierra Club is urging TVA to look at more energy options, including more solar with battery storage facilities to meet future power needs.
"TVA's proposal to replace old gas units with new gas units doesn't add up," said Jonathan Levenshus, a representative of the Sierra Club's Beyond Coal Campaign in Tennessee. "New gas plants carry far too many economic risks from storage technologies, environmental regulations, and commodity prices to be a good long-term strategy. Instead of spending hundreds of millions of dollars on new gas plants, TVA should accelerate plans to build new renewable energy and invest in battery storage and other clean technologies."
Last week, the Sierra Club released an assessment of U.S. utilities for their progress in helping to limit carbon emissions that the environmental group says is helping to heat up the planet and threatens a climate crisis. The Sierra Club said among the 50 biggest U.S. utilities, TVA had the second biggest increase planned in new natural gas production at more than 3 gigawatts of capacity in its long-range plans and TVA continued to have one of the largest amounts of coal-fired generation planned after 2030. Sierra Club gave TVA an "F" grade for its plans to retire coal, construct new gas plants and build new clean energy.
The Sierra Club blasted TVA despite its record over the past decade and a half to cut its carbon emissions by more than 60% and its pledge to cut carbon emissions below 2005 levels by 70% by 2030. TVA has shut down more than half of the 59 coal-fired generators it once operated and plans to soon idle its Bull Run coal plant in Oak Ridge. In their place, TVA has added more carbon-free nuclear power, solar, wind and hydroelectric generation.
But TVA's long-range plans also call for the federal utility to continue to operate its Cumberland, Gallatin and Kingston coal plants in Tennessee and its Shawnee fossil plant in Kentucky.
Levenshus said adding the new gas-fired combustion turbines at Paradise and Colbert at a likely cost of several hundred million dollars "could lock TVA into burning natural gas for decades into the future."
Hopson said TVA is still assessing its plans and the board has made no decision yet on new combustion turbines.
Contact Dave Flessner at firstname.lastname@example.org or 423-757-6340.