In order to meet the energy requirement for the next 100 years, the United States will have to consider following:

Tackling transportation. Despite the obstacles, the U.S. could make rapid headway by plugging holes in its leakiest energy-using sectors. Factories, homes and appliances could all be made more energy-efficient, but the biggest candidate for improvement is transportation, which accounts for almost two thirds of all U.S. oil consumption and which now uses 20 percent more oil than it did in 1973. Jet-fuel consumption has skyrocketed, rising 28 percent over the past five years to 1.3 million barrels a day. Meanwhile, America's 184 million cars, trucks, buses and other vehicles now swallow half the 17 million barrels of oil that the nation consumes daily.
Much of the impetus behind this growth has been cheap gasoline, priced lower in real terms until recently than at any other time in the past 50 years. One key to lowering vehicle-fuel consumption is thus raising the price of gas. The Gulf conflict may have accomplished that for now, but another option is to hike federal motor-fuel vehicle taxes, now at 9.1 cents per gallon of gas and essentially unchanged since the early 1980s. An increase of 12 cents a gallon would raise about $12 billion a year in new revenues, bringing the gas taxes a bit closer to the levels of industrialized nations such as Japan, where the tax is equivalent to $1.62 a gallon. More important, a tax hike would function as a price mechanism to spur consumers to conserve - taking more mass transit or even following the DOE's advice to put enough air in their tires.

Search for new oil reserves. Roughly 75 percent of the world's proven oil reserves lie in OPEC nations, while the U.S., the most heavily drilled country in the world, has only 4 percent. And America's aging oil fields are slowly petering out; domestic U.S. oil production has declined from a high of about 9.7 million barrels a day in 1970 to about 7.7 million barrels today. Even production on Alaska's North Slope near famed Prudhoe Bay - the boon that helped rescue America from its last energy crisis - is waning. Oil producers insist that the United States now has no choice but to launch exploratory drilling in places thought to harbor oil. At the top of their list are areas off the coasts of California, Washington and Oregon, and in the Alaska National Wildlife Refuge, or ANWR (pronounced ''Anwar''), about 60 miles east of Prudhoe Bay where an estimated 3.2 billion barrels of oil might be found.

The thirst for reserves could now prompt the biggest clash in years between Big Oil's backers and the growing environmental movement, which opposes what it views as an effort to ''Drain America First.'' Even the White House might shift gears: Only two months ago, for example, George Bush bowed to election-year pressures in California and Florida and announced a ban on oil drilling along much of the U.S. coast. The administration may also mount a new push for drilling at ANWR, a proposal shelved after last year's oil spill by the Exxon Valdez.

Even if new reserves are found, they'll be no quick fix: It could take up to a decade to develop production at ANWR. In the meantime, the administration will push for expanded tax incentives to encourage independent oil drillers, as well as settlement of disputes impeding planned offshore production. Chevron Corporation and state and local officials in California have locked horns over the company's bid to transfer oil by tanker - instead of by more costly and environmentally safe pipeline - from the new Point Arguello oil field off the coast of Santa Barbara. DOE Secretary James Watkins has sent emissaries to resolve the dispute, arguing that production from Point Arguello could increase U.S. oil supplies by up to 75,000 barrels a day.
Switch to natural gas. Gasoline can be made from coal and oil squeezed from shale, but oil's price would have to top $40 to $60 a barrel to make the effort worthwhile. A better alternative may be to expand use of natural gas, a relatively clean fuel that can be substituted for oil in both transportation and stationary use. Americans will use 18.3 trillion cubic feet of natural gas this year, 93 percent of it from the U.S. and most of the rest from Canada.

If trucks or buses were equipped with high-pressure tanks like the cylinders used by scuba divers, many could be run on natural gas. The United Parcel Service is one of several companies now converting a portion of their truck fleets to the fuel - and within five years, the American Gas Association estimates, natural-gas use could displace 1.3 million barrels of oil a day. To speed up conversion, the Bush administration has called for swifter regulatory approval of proposals to build new gas pipelines. And the gas industry is backing provisions in Clean Air Act amendments now before Congress to promote the switch from imported oil to natural gas.

Electric cars and nukes. Running cars on liquid-alcohol fuels such as methanol, made from natural gas, or ethanol, made from corn, is another alternative - though widespread use could quickly gobble up the nation's corn crop and all domestic supplies of natural gas. Using electricity to fuel cars might make more sense, since vehicle batteries could be charged at night when power plants have surplus capacity. General Motors and Chrysler are at work on electric cars and vans with a range of about 120 miles, making them contenders for many commercial uses and commuting to work. GM will produce the first modern U.S.-made electric van later this month; electric cars could be on the market by the mid-1990s, though expensive batteries could make them pricey.

But greater use of electricity would be no panacea. The nation already uses 50 percent more electricity than it did in 1973 - and with electric use growing rapidly, areas along the Eastern seaboard and Florida are now contending with power shortages. To meet the growing need, the nation's electric power grid will have to be enlarged by one third to one half by the year 2000, at a cost of as much as $800 billion.

These giant new power plants will have to be fired by coal or nuclear power - and because the clean-air amendments will make it harder and more expensive to burn coal, the atom may soon have the competitive edge. As it stands, nuclear energy provides only about 7 percent of U.S. energy needs, compared with 30 percent in France and 32 percent in Sweden. The Nuclear Regulatory Commission is now seeking ways to cut the time it takes to license U.S. nuclear power plants, in part because related public hearings and lawsuits now stretch out plant development to as much as 11 years. Yet public fears of accidents and worries about nuclear-waste disposal seem certain to hem in new nukes.