THESE ARE frustrating times for the environmental movement. Not a day passes without some high-ranking official claiming that environmentalists have stopped a key pipeline, critical refinery or badly needed power plant. Increasingly, environmentalists are portrayed as being "against" everything and "for" nothing. To listen to some observers, our answer to the energy crisis is to halt economic growth and simply live on less.

To back up their claims, these people point to the environmental community's endorsement of conservation as a solution to the energy crisis. To them, conservation equals sacrifice. It means turning their thermostats down to 65 degrees in winter and up to 78 degrees in summer. It means restrictions on the use of their automobiles.

The response to this conviction has been predictable. Tired of hearing arguments for more and more conservation, and thus more and more sacrifice, the Congress and the president have both started pushing for a massive synthetic fuels program. To make sure that environmental restrictions do not slow down the new effort, an Energy Mobilization Board would be empowered to sweep away all obstacles posed by environmental or other statutes. According to this view, the environment has become an expensive, and increasingly expendable, luxury.

Despite warnings from environmentalists and others about the risks inherent in such an approach, the administration is still committed to a multi-billion-dollar program to produce 2.5 million barrels of oil a day from "synfuels" by the early 1990s, although it has agreed to a somewhat smaller initial effort. Meanwhile, congressional proponents continue to insist that synfuels must be the centerpiece of America's efforts to reduce oil imports.

Before we take the plunge, however, we owe it to ourselves to take one last hard look and ask, "Is there another way?" Is it really necessary to spend tens of billions of dollars to meet the president's oil import reduction goals? Have we come to the point where we must sacrifice our health, our air, our water and our land to meet the nation's energy needs? If not synfuels, is more sacrifice the only answer? The answer to all of these questions is a resounding no -- if we are willing to take a careful look at an alternative plan.

Like the proposal advanced by the president, this plan involves a bold, crash effort. Like the president's proposal, its goal is to reduce America's dependence on imported foreign oil supplies by 4 to 5 million barrels a day by the late 1980s.

There, however, the similarity ends. Unlike the president's proposal, this alternative will not require $100 billion or more. The costs should be one-third to one-half that figure. Furthermore, the proposal will not wreak havoc with the environment and threaten the public health. Perhaps most important, the alternative will allow us to slash foreign imports much more quickly than would be possible under a massive synfuels program.

Instead of squeezing oil and gas from coal and shale, this program would tap America's largest known remaining oil reserves. These reserves are so large that they dwarf the recent discoveries of oil on the north slope of Alaska. Moreover, this reserve can never be pumped dry. It will provide oil long after the last drop has been sucked from Alaska or even from oil shale in Colorado or coal in Wyoming.

Despite this vast potential, this oil reserve does not appear on any U.S. Geological Survey map. It also does not appear on any oil company maps. It can be photographed, but only by using special infrared techniques. To map the potential size of this vast oil reservoir, we will need millions of these infrared photographs. The photographs, however, will not be of geologic formations, but rather of buildings -- homes and factories and businesses. What these photographs will show is waste heat -- heat from millions of structures as a result of our inefficient use of energy.

Recovering this oil from this new field does not require exotic technology which will destroy the environment and bankrupt the federal treasury. Indeed, much of it can be recovered by very simple techniques such as improving insulation in existing buildings and increasing the efficiency of furnaces. These techniques are well understood and, in most cases, very inexpensive.

The potential size of this oil reserve is staggering. According to figures developed by the Carter administration, simply upgrading the energy efficiency of residential and commercial buildings could reduce oil imports by 2.5 million barrels a day by the late 1980s. This saving is equivalent to the entire projected production of the synfuels industry proposed by the president.

While recognizing the potential of this source, the White House has conceded that its program to save 500,000 barrels a day represents "only about 20 percent of the potential savings achievable by the retrofit installation of conservation measures in buildings." The failure to exploit this vast oil resource fully is especially surprising in light of White House estimates that the equivalent cost for improving the energy efficiency of buildings is below $10 a barrel and that this represents "the cheapest means of reducing oil imports . . . " This figure stands in stark contrast to the White House estimate of a $35-to- $40-a-barrel cost to develop synfuels.

Even more important, this 2.5 million-barrel-a-day reservoir trapped in residential and commercial structures is just the beginning. Equally significant reserves remain to be tapped in industry and transportation.

In factories, for example, large quantities of waste heat from industrial processes can be used to generate electricity. A study by Dow Chemical Corp., which uses such "cogeneration" to meet 75 percent of its electrical needs, estimates that by 1985 industry could economically justify producing about one-third of its electric power through cogeneration. This would also reduce the cost of electricity significantly.

In another area, relatively simple improvements in the combustion efficiency of existing boilers and furnaces could save an additional million barrels of oil a day by 1990. Within the transportation sector, a serious commitment to car and van pooling could save a significant portion of the 309 million gallons a day burned by cars and trucks.

Taken together, these measures could "produce" more oil than all of the suggestions advanced by the administration. Indeed, according to a study entitled "Energy Future," prepared by the Harvard Business School, we could "produce" 5 million barrels of oil a day by the late 1980s simply by tapping known "conservation reserves."

Perhaps most important, tapping these reserves will not require personal sacrifice. We are not talking about raising thermostats to 78 degrees in summer and lowering them to 65 degrees in winter. For too long we have equated conservation with sacrifice. We have been told that to conserve we must sweat in the summer and freeze in the winter. What we have not been told is that all of this is unnecessary. Simple and inexpensive improvements in the way we use energy can ensure the same lifestyle as we now enjoy without sacrifice.

As a country, we now stand at a crossroads. One path leads toward synfuels, cost overruns, and wide-spread environmental destruction. The other alternative -- the "confuels" path -- presents us with a cheap, quick and environmentally safe means of reducing our oil imports. Both logically and politically, the choice should be clear.