President Carter conceded yesterday that Congress will not enact his energy program - on which he has staked much of the success of his first year in office - during the few days it has left this year.

With Congress hoping to adjourn for the year by the end of this week, White House officials for the first time openly questioned whether even a general agreement on energy legislation, paving the way for enactment early next year, can now be reached.

Deputy press secretary Rex Granum said the President is "increasingly concerned" about that prospect coupling that pessimistic assessment with a warning about the consequences should the congressional debate over the energy drag on much into the new year.

Continued disagreement over energy, Granum said, "will make final drafting and early action on economic policy - particularly tax-reductions - much more difficult."

Moreover, he said, "it will raise questions in the minds of foreign observers about our ability as a nation and a political system to deal with a problem that has been with us for a very long time. And certainly it will prolong the period of uncertainty that is unavoidable when complicated legislation is under consideration."

Earlier this year, the House approved energy legislation that was similar to what the President proposed in April. But in the Senate passed version of the legislation, Carter's key proposals were killed or severely weakened. The two sides have since been locked in disagreement in several conference committees, with little sign of progress on the two key issues - an administration proposed wellhead tax on oil production and the price and regulation of natural gas.

At a White House a senior official sought to emphasize the domestic and international importance Carter places on the energy legislation.

Internationally, the congressional deadlock over energy has already caused the President some embarrassment. He canceled his much-publicized nine-nation trip last month, ostensibly to fight for the program on Capitol Hill. A scaled-down version of that trip now is set to begin Dec. 29, with the clear prospect that Carter will not be able to point to a new national energy plan to assauge foreign concern over the growing cost of the U.S. oil imports.

Two of the stops the President plans to make are in Iran and Saudi Arabia, key members of the Organization of Petroluem Exporting Countries, which the administration is pressing to hold down world crude oil prices. But without an energy plan of his own, Carter "will not be in the strongest position" to make that case, the White House official said.

Domestically, both the energy package and the Social Security legislation are crucial to the administration's economic planning. The President plans to propose tax cuts to offset much of the cost of those programs next year, and obviously difficult task if he does not know the final shape of the energy package.

Moreover, as Granum and other White House officials noted, the continued deadlock over the energy package is likely to feed business uncertainty over the general direction of the economy in the months ahead.