The Tennessee Valley Authority burst upon the Depression-era South in the 1930s as one of President Franklin D. Roosevelt's many programs intended to stimulate recovery.

TVA was going to create lots of jobs by building big dams on the Tennessee River - harnessing the river for "navigation, conservation and flood control."

Oh, incidentally, the TVA dams would produce electricity through "byproduct" hydro-generation at its dams.

But TVA's electricity turned out to be the "tail that wagged the dog."

The threat of TVA's taxpayer-subsidized "cheap" socialized electricity forced the free enterprise Tennessee Electric Power Co. and its parent Commonwealth & Southern Co. into surrender.

Many people cheered as TVA's "low-cost" electricity spread throughout the rural South.

Over the years, the growth of industries, businesses and housing in the South exceeded the capacity of the TVA dams to generate electricity. So TVA built many coal-burning electricity-generating plants.

Coal is relatively cheap, but it created huge air pollution problems. So "scrubbers" had to be installed at substantial cost to reduce the release of objectionable emissions.

But now lawsuits involving four states and continuing emission problems have resulted in a TVA agreement to shut down a total of 18 of its older coal-burning electricity-generating units at its plants in New Johnsonville and Rogersville, Tenn., and in Stevenson, Ala.

TVA also expects to have to spend $3 billion to $5 billion for more pollution controls at its coal-burning plants, and to spend $350 million for projects promoting "environmental improvement" over five years.

As population, businesses and industries increase, there surely will be increased demand for electricity.

With not much prospect of significant additional power generation at dams, and with many coal-burning units being shut down, there has been great appreciation of TVA's electricity-generating nuclear plants. But there is now alarm about nuclear power as a result of serious damage to a nuclear plant in Japan. An exceptionally powerful earthquake and resulting tsunami caused that damage.

How will our growing home, business and industrial electricity demands be met?

What will the costs be?

TVA fortunately is not abandoning nuclear production, though it is taking reasonable precautions. There is also some electricity production from natural gas. And there will sensibly be conservation to reduce wasteful electricity use.

But what other power sources can be developed without objectionable emissions, dangers and other negatives - and without far higher costs that could hinder economic growth? Solar and wind power have not yet proved really cost competitive.

The challenges are great, and necessity, it is said, is the mother of invention.

But there is very little certainty about what will happen in the near future as we seek to meet our energy needs at a reasonable cost.