That proposal for wind power transmission ought to be revived. Moreover, solar power could go a long way toward cleaning up electricity production in the South; in fact, utilities in the Carolinas, Georgia and several other states are committing to reasonably ambitious plans.

It is true that under a new chief executive, Jeff Lyash, the T.V.A. has recently made noises about building a lot of solar plants. But they seem to be just noises: The actual budget the T.V.A. has adopted calls for a more modest solar program that will most likely leave the Tennessee Valley lagging much of the South.

None of this necessarily means that Mr. Sanders is wrong in principle. The most rapid emissions cuts in advanced economies occurred in France, Canada and South Korea in the 1980s, as a result of speedy buildouts of nuclear power plants led by state-owned enterprises. Given the right mandate, a government-owned authority like the T.V.A. might well be able to move faster than private utilities in adding renewable power to the electric grid.

“If someone could make a compelling case that you need to put this country on a war footing to solve the climate crisis, then T.V.A. could be a tremendous asset for doing that,” said Stephen Smith, the executive director of the Southern Alliance for Clean Energy, an environmental advocacy group that has long battled with the T.V.A. “But you’d have to clean house.”

A core problem is that the T.V.A. really has no boss, other than the president, who appoints the board members to staggered terms. When Barack Obama was in the White House, he avoided pushing the T.V.A. very hard, not wanting to pick fights with Tennessee’s slightly moderate Republican senators at the time.

So the agency, long dominated by a conservative engineering mind-set, has gotten little pressure from Washington to move faster on the energy transition. But it is starting to get pressure from the other direction: cities that buy power wholesale and resell it to their citizens. Memphis, for instance, is considering pulling out of the T.V.A. system and cutting its own deals for clean power. If the T.V.A. remains so stuck in the past, we encourage other cities in the region to look hard at their options. They certainly need to resist the T.V.A.’s recent efforts to strong-arm them into signing new 20-year power contracts.

The real shame of the situation is that the T.V.A. could achieve a lot in short order, if it chose to do so. It already has some of the lowest emissions in the country. It operates seven nuclear power reactors, and is the only utility to get one built and running in this century: the new reactor at Watts Bar began operating in 2016. The T.V.A. still has the dams that it built in the 20th century, another low-emitting source of power. And to its credit, the T.V.A. board voted last year to shut down two particularly dirty coal plants, despite protests from President Trump.