Because expensive energy will be a permanent fact of life for rich industrial countries, creating "uncertainties in the investment climate," poor nations would be wise to count on less generous development help in the future.

That is the central conclusion of this year's annual report by the International Finance Corp., a World Bank affiliate that works through the private sector of developing countries.

The IFC annual report, published yesterday, will be followed shortly by similar documents from the World Bank and the International Monetary Fund, all preceding the joint annual meetings in Belgrade Oct. 2-5.

As the industrial nations, facing lower economic growth, are forced to retrench, the developing nations increasingly will have to look to their own resources and initiatives, the report said.

Specifically, the less-developed nations were urged to pursue more rapid growth of trade among themselves, and to diversify their exports to the industrial world "into more -- sophisticated engineering and chemical products."

Another suggestion is "the exploitation of indigenous energy resources." The report pointed out that 60 developing nations that aren't members of the Organization of Petroleum Exporting Countries now produce only 6 percent of the world's oil, while they account for more than 40 percent of total prospective oil areas. The IFC said it would give special attention to helping finance exploration and development of new energy sources in less-developed countries.

Reviewing the recent past, the IFC said that the developing countries had maintained their economic growth well into the early part of this year with the help of "exceptionally favorable access to international capital markets."

Although official government aid was stagnant in 1978, private international lending to the poor countries surged by almost 70 percent, including a near-doubling of Eurocurrency credits. All told, private capital investment came to about $52 billion, making private flows dominant in the external financing needs of developing countries.

But the report was quick to point out that two-thirds of the Eurocurrency loans went to the 10 so-called "advanced developing countries," and another sizable chunk went to oil-exporting countries. This means that smaller and poorer developing nations got little help from the private international capital markets. These countries must depend on official financial assistance.

The external debt of the developing countries was estimated at $250 billion at the end of 1977, an increase of $90 billion since 1972. But the IFC said this growth has been supported by increasing gross national products and exports.

The ratio of external debt to GNP in the developing countries increased only "marginally" from 16 percent to 19 percent, while the debt service-to-exports ratio actually declined from 16.5 percent to 15.5 percent, according to the report.

Even with the large increase in borrowing in 1978, "only minor deterioration in these ratios seems likely for 1978," the report said.

The agency said it approved $425 million in equity and loans during fiscal 1979, including $38 million for expansion of fuel and non-fuel minteral resources. Total IFC lending -- spread over 48 projects in 33 countries -- is up 26 percent over fiscal 1978.