If this is Thursday, David Freeman is puttering toward his first day as chairman of the Tennessee Valley Authority in a beat-up 1970 Opel, tossing about ideas on how to fulfill President Carter's command to lead the utility giant out of the wilderness.

Not everybody agrees TVA is in the wilderness. Chief among them is Aubrey (Red) Wagner, who retires as chairman today. An engineer with baggy eyelids that droop like a basset hound's ears, he has a TVA pedigree that stretches all the way back to 1934.

During that time - including 15 years as chairman - Wagner has watched the agency dump 12 times more concrete, rock and earth into rivers than the Pharoahs put into the pyramids. As a man who also watched the agency turn red clay into lush pastures, Depression into a booming economy, floods into lakes, and darkness into an all-electric valley, Wagner doesn't cotton to arguments that paradise has eluded the region or that TVA is in Carter's words, "just another utility."

Tomorrow morning - if all goes as planned - Red Wagner will be bass fishing on the agency's Watts Bar lake, casting a rod that has no more control over the fish than that of the other retirees who haunt the lake.

Fifty miles away, on another TVA lake, another former director, William Jenkins is crappie fishing and giving thanks that his two-week-old resignation means he, too, no longer has to worry about endangered snail darters, electricity rates, and Environmental Protection Agency bureaucrats.

That leaves TVA, both condemned and praised as America's first great flirt with socialism, in the sole hands of the controversial Opel driver who acknowledges his morning metabolism hits and misses like that of his car engine. Before the day is out, however, he will catch fire and wear out several worshipful aides, further enrage his critics and complete plans for President Carter to meet with TVA employes in Knoxville on Monday.

"The president is very much aware of what's going on down here," Freeman claims. "He knows he's got two crucial appointments to make to the [three-member] board, and he wants very much to turn TVA into what it historically has been - a laboratory for the nation. We're going to get back in the limelight where we belong."

Freeman's ambitious hopes to remake the federal authority in the image of the Carter energy plan he helped write as a presidential adviser - to turn it to conservation, solar power, and demonstrations of new ways to burn coal and buy nuclear waste - have taken hold very slowly since he came aboard last August.

At the agency's press office, the staffers have had a grueling nine months trying to ride the waves created by Freeman's rift with what, until the recent resignations, was the board majority. The staffers used to fashion jokes about his playing God." Now, sums up one press officer, "If this guy can lead us out of the wilderness to the Promised land - get the strip-mine critics, the nuclear critics and the Tellico Dam critics off our backs - by God, we'll go."

Freeman, who jokes about attacks on his arrogance, does not claim he has yet turned the agency around, just that he has laid the groundwork for the agency's critics to have a say in its policy. "I've spent the last nine months looking over the property and talking to people who have not seen a TVA director in the flesh for decades," he says.

The turnaround was crystallized at a recent board meeting. The Audubon Society president with a big hat, the Sierra Club president in a black suit, and the Tellico Dam area landowner in the working woman's garb, all came to praise Freeman. The men in the gray pinstripes representing TVA's 160 power distributors, Stauffer Chemical Corp., and Consolidated Aliminum Corp. all came to condemn him for not wanting to keep rates down.

Freeman reminded the power distributors and industry leaders, who warned that their plants might close, that the TVA act required that power be sold to industrial customers at rates that would allow lower costs for residental consumers. It is also clear that the residents of the valley have come to aquate the rising bills for their all-electric homes with sin, despite the fact that TVA rates are 60 percent of the national average.

The TVA board, at Freeman's urging , yesterday turned down a staff request for a 12 percent across-the-board rate increase, and instead approved an 8.5 percent increase.

While he has opened discussions with the Interior Department to try to solve the problem of the snail darter vs. the Tellico Dam, and has negotiated a consent decree with the EPA to settle the agencies air clean-up problems, Freeman acknowledges he has yet to turn the agency upside down.

"I don't think we've decided a single important issue since I've been here," he said in an interview Tuesday.

Freeman admits his biggest problem is overcoming his image of being a "no growth" man out to tear down the "works of [former chairman] Wagner." That image was fueled by a Harper's magazine article last August by editor Lewis Lapham that attacked Freeman as a member of the "technocratic class" which was scheming to use the energy crisis as a means of taking over the nation's economy.

The statements in that article have been excerpted and recycled for a number of attacks on Freeman in the Valley press. "My only answer to those attacks is to say, 'Watch us grow'," Freeman says. "We'll be the first region in the country to achieve full employment. We're not so poor, though, that we have to beg the energy-intensive industries to come here and pollute the land."

Yet some TVA staffers - willing to be quoted by name only "if I decide to leave" - complain that Freeman fails to understand that the TVA - the nation's largest utility - is also a massive corporation. It controls patents on 75 percent of the nation's fertilizers, mines uranium in Wyoming, digs coal in Alabama, Illinois and six other states runs the nation's fifth largest navigable river, controls the spending of over $2 billion annually in revenues and these staffers say, it has to operate like all corporations.

Freeman's response is that he "has been in the TVA trenches" for 13 years as a TVA engineer and lawyer. Growing up the son of a Chattanooga umbrella repairman, he says, "my dream was to work at TVA. You don't go out and wreck an agency when that dream puts you on the board. Anyhow, if the critics will stick around a while, they'll see that the lights are not going to go out."