The biggest threat to energy sufficiency in America is not the foreign oil cartel or bungling federal regulators, but the bitter impasse between economic expansionists and environmentalists over future energy development.

And it is an impasse that need not exist.

These are the central conclusions of a team of scholars that spent the last three years pondering the nation's energy dilemma. The team's findings are contained in a thick report issued here last week by Resources for the Future (RFF), an energy think tank.

RFF President Charles J. Hitch wrote in a preface to the report:

"The important, reassuring (and unexpected) conclusions of the authors is that, despite differences in values and goals, Americans can reach consensus on broad issues of energy policy if they understand the facts and are willing to settle for the hard core of their goals, sacrificing extreme positions in the recognition that everyone must give up at least a little.

"We can have a great deal of conservation and environmental improvement without imperiling economic health and growth, and at the same time we can reduce our dangerous dependence on imports."

At first glance, that sounds like a utopian prescription for sealing friendships between lions and lambs.

But the authors of the study, entitled "Energy in America's Future: The Choices Before Us," said both sides are going to have to pay a price, as are the various consumers who use energy.

The environmentalists will have to permit the further development of nuclear power and of new technologies for burning coal and mining oil shale.

The expansionists will have to start paying the costs of major health, safety and environmental regulations that govern energy production, so that the Earth remains a decent place to live.

In turn, the report said, the environmentalists "must surrender" their view that most economic development is bad and that most energy development is destructive "so that the expansionists can look to the future with some assurance."

Neither side should be expected to renounce its aims and principles simply in an effort to get along with the other, the report said.

A detailed solution to the nation's energy problems was not outlined, but the struggle toward energy sufficiency will be long, arduous and expensive, the report said.

Some unavoidable consequences of developing new energy sources, it said, would be the decontrol of domestic oil and gas prices, federal subsidies for energy conservation in homes, businesses and industries, and federal market guarantees for synthetic fuels made from shale, coal and wastes.

The report also favored expansion of conventional nuclear power plants and the long-range development of fast-breeder nuclear reactors that could increase the useful life of uranium fuel 60-fold.

It was not as optimistic about the role of solar power as another recent study by Harvard economist Robert Stobaugh and writer Daniel Yergin. The Harvard team had plugged solar power as the nation's ultimate salvation.