"GIGANTIC ABSOLUTE AUCTION! $80 MILLION REPLACEMENT VALUE!" announced the classified advertisement in The Pittsburgh Press.

It gave details of a private scrap metal auction by a $25 million Energy Department synthetic fuel pilot plant called Synthoil and its $10 million sister project, Synthane. Some of the plants' machinery, the ad said, was "NEVER BEFORE USED!"

Department officials liken the auction to throwing away a somewhat expensive test tube when an experiment fails. But in the energy field, like other big-ticket research areas, the success of an experiment depends not just on chemical interactions but economic ones.

What the auctioneers were hawking in the Pittsburgh suburb of Bruceton was the flotsam of the mid-1970s, another era in the fast-changing world of energy development. Arab nations and Iran had cut off the United States' oil; energy prices were exploding. Research into synthetic fuels, the process of making oil and gas from coal and oil shale, was a bureaucratic darling whose budget grew dramatically.

But in 1979 and 1980, DOE research turned from these small plants to much larger test projects, which could convert 10 or 20 times more coal into oil or gas. Then, a worldwide glut depressed oil prices. Synthetic fuels cost too much to be an attractive alternative energy source. Government support waned.

Now, from Appalachian coal fields to Texas and Washington state, four of the government's five pilot plants, hulking monuments to its short-lived enthusiasm for small-scale synfuels experiments, are being sold for scrap.

Synthoil is the only one that never crunched an ounce of coal.

Paul Yavorsky, 58, an engineer who worked on synthetic fuels research for 23 years, 13 of them with the DOE's Pittsburgh Energy Technology Center, was the father of the plant, and may have been the only person to mourn as it was dismantled.

In 1970, Yavorsky joined the Pittsburgh center, then part of the Interior Department's Bureau of Mines, to try for a breakthrough in the two-century-old science of synthetic fuels production, an alchemy that once produced gas from coal to light the lamps of London.

Yavorsky's research into coal liquefaction was conducted in obscurity for several years until 1975, when he was transferred--along with the center--to the new Energy Research and Development Administration. That year the budget for research on fossil fuels more than doubled, and the government was encouraging a proliferation of pilot synthetic fuels projects, often in partnership with energy-producing and energy-consuming firms.

In his laboratory, Yavorsky refined the existing process for turning coal into oil, tested it in a room-sized plant, then pushed for the construction of the pilot "Synthoil" plant, which was designed to take 10 tons of coal a day and turn it into oil through a complex process of pulverizing, heating, pressurizing and catalyzing it.

"For an engineer, it's a wonderful thing to turn this dirty lump of coal into something clean and useful," said Jonathan Lash, an official of the Natural Resources Defense Council who co-authored "The Synfuels Manual." "It's always held the promise of something wonderful just around the corner."

Yavorsky's coal liquefaction project was one of several to attract the attention of officials in ERDA and its later incarnation, the DOE. The various processes all had the same end product and used similar technology, but, like entrants in the Indianapolis 500, each was vying for a technological edge.

Construction contracts for the Synthoil plant were let in 1975. In 1978, when the plant was nearly finished, the department solicited bids to run it. Several firms expressed interest.

But a week before the deadline for bids, the request was withdrawn. Yavorsky got a telephone call from Jim Batchelor, director of the coal liquefaction division of the DOE's Office of Fossil Fuels. Batchelor said that Energy's policy-makers had turned thumbs down on Synthoil.

"We were beginning to back too many versions of things. The results in the earlier smaller scale of Yavorsky's project were not promising enough to continue the thing," Batchelor said recently.

The Synthoil process, the DOE decided, was more expensive and less efficient than some of the other pilot plants. Also, though this was not said, most other pilot plants had corporate support from major oil companies.

In the government-industry buddy system that characterizes energy research, Synthoil was an outcast. It closed before it opened.

"I 'wasted' eight years of my life developing that process," said Yavorsky ruefully. "But I didn't waste them. Some extremely valuable work came out of that, some new information."

For a few years, some officials tried to interest industry or an agency like the Defense Department in taking over the plant.

This year, the DOE took bids for the disposal of the $20 million worth of equipment at the plant. The winning bidder, a New York plumbing firm, paid $300,000 for the machinery and hired autioneers to see what they could get for it. The office buildings were kept for the Pittsburgh center's use.

Synthane, the sister plant designed to produce methane gas that could be marketable in interstate pipelines, operated for several months before a boiler blew.

"Part of the problem was the speed with which we went from a rather sleepy attitude toward synthetic fuels to a big buildup period in the early 70s," said Batchelor. "We did eventually start up more things that we should have . . . . Rather than follow that path because of inertia, the time came for picking and choosing."