THE JUST-RELEASED report of the National Academy of Sciences -- "Energy Policy in Transition 1985-2010" -- should be read in the light of its peculiar history. The committee that produced it was no group of dispassionate experts, coolly subjecting a narrow technical issue to scholarly analysis.They tackled a problem that is as much social and political as it is technical, and they discovered that their disagreements were as deep and abiding as those that frustrate the making of energy policy inthe most political of forums. The report has finally emerged -- nearly three years late -- but there is general agreement that the committee's differences, despite the years of work and contributions by 350 individuals, remain as deep as they were five years ago.

The study is based on a number of different estimates of plausible energy use in the year 2010. These cover a very wide range of possibilities, from 15 percent less than today's use to more than twice as much. The enormous uncertainty that is embodied in that range points up the study's most important conclusion: managing energy demand rather than supply is the key to energy policy. No other activity affords such sorely needed room for maneuver. Based on its economic models, the study also reached the startling conclusion that, if the transition is managed gradually and sensibly, economic output can be doubled without increased energy use (or, put technically, the country's energy/GNP ratio can be halved).

Putting these two together, the report concludes, as so many other studies have, that energy conservation "should be accorded the highest priority in national energy policy." The absence of a genuine commitment to energy conservation remains the greatest and most puzzling failure of this Congress and of every Congress since 1973, when the first national energy study, commissioned by President Nixon and chaired by nuclear enthusiast Dixy Lee Ray, reached the identical conclusion.

The study had to ignore the possibilities of unpredictable technological breakthroughs. But it does point out that certain breakthroughs -- for example, the development of efficient, inexpensive solar photovoltaic cell or the discovery of convenient and cheap ways to store electricity -- could dramatically alter the energy picture.

The controversy that enveloped this study from its inception was no accident of committee selection. The country is in the midst of a fundamental transition from an era of cheap, fossil-fuel energy to on of expensive energy based on a still uncertain combination of fuels, and passages to an unknowable future are always murky, and therefore controversial, ventures. For several years the national debate has raged over whether or not the transition has to happen: the academy's report makes clear that the shift is now indisputable. What the report fails to show, because its analysis was completed two years ago, is equally important: that this transition is occurring much faster than even the most farsighted experts predicted.