| Memphis Commercial Appeal
The Tennessee Valley Authority has cut capacity at its Allen Combined Cycle Plant on President’s Island at the request of Memphis, Light, Gas and Water. The move is to conserve water amid low water pressure citywide.
The cuts amount to about 33% of the plant’s 1,050 megawatt capacity, meaning that TVA needs to send Memphis more power to make up for the cuts.
TVA CEO Jeff Lyash said the federal power provider’s move to curtail some of Allen’s production will have no impact on keeping the lights on in Memphis or across TVA’s seven-state footprint. For each of the power companies that belong to it, TVA, not the local power company, is responsible for making sure there is enough electricity to serve them.
TVA, like all utilities, has something called a reserve margin — the amount of energy supply it holds back to reach peak demand. That margin is about 26% in the wintertime for TVA, meaning it tries to have 26% more energy generation than it needs.
“We have to switch some of the transmission systems to reconfigure so power still flows and [we] will ramp up some other assets on the system, less efficient assets, but still assets that are in our reserve margin,” Lyash said. We’ll adjust[and] will maintain the reliability of the system and will support MLGW until they can return that makeup water system.”
TVA is MLGW’s largest water customer
MLGW is the largest local power company in the TVA footprint. It represents about 10% of TVA’s revenue from electricity generation. TVA is also MLGW’s largest water customer, meaning it buys more water from Memphis than anyone else.
That water is used to run the steam turbine at the Allen Plant. There are two natural gas turbines at the plant, which run on fuel and generate electricity that way. The heat from those turbines is used to boil water for the steam turbine at the plant, which generates more electricity.
TVA stopped taking water to run the steam turbine last night, effectively shutting that asset down and cutting 350 megawatts off the plant’s capacity. For context, MLGW’s electric load — or energy demand — was 2800 megawatts on Tuesday during the coldest bit of the deep freeze that gripped the South. Allen supplies some, but never all, of Memphis’ electricity.
TVA CEO continues to pitch Memphis, and highlight risks of leaving
The TVA chief executive used the discussion of Allen to bring up the several billion dollar question — Memphis’ discussions about leaving TVA and joining the Midcontinent Independent System Operator, an electric grid network commonly known as MISO. His comments came at a time when utilities inside MISO, in Mississippi, Arkansas and Louisiana are still struggling to meet demand and not everyone has power.
“If MLGW wants to head away from TVA, it has a way to do that, and it can do that,” Lyash said. “But the complexity of the business, the risk that you’re taking by stepping out on your own; exposing…