Knoxville, Tenn. — A few blocks from the world's fair here, which has energy as its theme, another national energy showcase is receiving much less public attention.
Yet decisions being made in this other showcase, the Tennesee Valley Authority (TVA), are a better reflection of national issues regarding nuclear power and Americans' electric bills than the glitter and hoopla of the fair.
In a recent, controversial decision reflecting a national trend, the TVA has confirmed that its love affair with nuclear power is truly cooling down.
In what was to have been the nation's largest concentration of nuclear power plants (17), construction on nearly half the TVA plants has been postponed. The most recent decision on three plants brought to eight the total now postponed. None have been canceled.
However, in a Monitor interview, TVA board member S. David Freeman said it is likely that five of the eight postponed plants will never be built. ''The facts were overwhelming,'' said Mr. Freeman, who voted with the 2-to-1 majority to postpone the three additional plants. ''We couldn't buck studies showing coal plants could be built cheaper.''
Two years ago, when asked whether the TVA had compared the costs of coal plants with the cost of halting construction on partially completed nuclear plants, the TVA was unable to point to any such research. Now, says Mr. Freeman, such studies have been made.
Nationally, new orders for nuclear plants have ground to a halt as safety-related and other construction costs have sent their price skyward. Some plans for plants have been canceled.
Other developments at the TVA reflect related national issues regarding US electric bills:
* Conservation vs. consumption.
''We (TVA) have made the switch from promotion (of electric power) to conservation, from abundant use to frugality,'' said Mr. Freeman.
The TVA offers free home inspections and makes loans for the cost of insulation and other related energy-saving changes, allowing repayment on monthly electric bills.
While praising TVA's conservation programs, an electric power distributor official criticizes a TVA plan to charge higher rates to consumers using large amounts of electricity.
For years the TVA pushed higher electric consumption, when rates were cheap, says Jerry Campbell, executive director of the Tennessee Valley Public Power Association. The proposed rate changes would hurt the poor, especially, since many of them live in ''leaky homes,'' he says.
He also criticizes postponement of the nuclear plants, challenging TVA cost figures and saying forecasts of lower power usage could become a ''self-fulfilling prophecy.''
Another TVA board member, Richard Freeman (not related to S. David Freeman), says that ''innovative'' approaches to energy and other issues are one of the strengths of the TVA. Congress has cut appropriations from about $150 million several years ago to about $120 million, but much can still be done even with this amount, he says.
He points to the TVA role of economic development of the Tenneseee Valley and says low-cost, TVA-assisted self-help programs are under way in some small towns.
Some 75 percent of the nation's fertilizers in use today stem from processes developed at TVA laboratories, he points out. TVA is also about to open a coal gasification plant for use in fertilizer production.
Congressional staff members on committees that oversee and fund the TVA say committee members are generally pleased with the way the TVA is proceeding. Last year, President Reagan replaced S. David Freeman as chairman of the board by a power industry official, Charles Dean, after complaints about rising TVA utility rates.