THE FIVEFOLD increase in the real costs of energy has put the 90-odd, oil-importing, developing nations in a desperate bind. To break out of poverty they must make all kinds of expensive investments. But for most of them, energy costs are consuming what money is available and contributing to a soaring debt as well.

The good news is that their energy needs are small. These 92 nations collectively use only about 12 million barrels of oil a day -- three-quarters of daily U.S. consumption. For about 60 of them, daily imports are less than 10,000 barrels. Amounts of oil that are hardly noticeable in American terms can make the difference between near bankruptcy and a chance for affluence for them.

Predicting where undiscovered oil reserves may lie is still a highly uncertain business. The only sure way to find out is to drill exploratory wells. But drilling is expensive, complicated and risky. This is one reason that only 5 percent of current world exploration is taking place in a collection of countries that are estimated to hold up to 40 percent of the world's prospective reserves. There are other factors: political instability, the fear of expropriation and the expectation that none of these countries harbors fields large enough to make a dent in the needs of an industrialized country. Still, the potential exists for many small to medium-sized finds. A field that might be insignificant to Exxon would make all the difference to Benin or Thailand or Cyprus.

Clearly, there is a need for an institution to provide a source of money, insurance against political risk and access to planning and management expertise. It exists in the World Bank, which is already lending money for energy development. But the need far exceeds the resources of the bank, which last year recommended the creation of a new energy affiliate that would double current lending goals.

Internal debate on the merits is still going on within the Reagan administration, which was not initially keen on the idea for ideological and economic reasons. But the administration professes a strong commitment to developing the energy resources of non-producers and to giving the World Bank and important role -- along with OPEC and private capital. Some argue that there isn't enough money for a U.S. contribution. Others point out that every barrel of imported oil replaced by new finds in the Third World will ease pressure on the world market, drive down prices, stretch out reserves and lessen American reliance on the volatile Persian Gulf. Ultimately, moreover, economic growth in Third World countries will contribute to their political stability and diminish opportunities for Russian troublemaking, not to mention open markets for American products.