Department of Energy, targeted for extinction by the Reagan Administration, has frozen all promotions indefinitely. The freeze will remain on until DOE gets its political team in place, and new leaders have evaluated jobs and indivual employes who have been promised promotions. Other departments planning shakeups, or slimdown exercises, may follow suit.

Shortly after it took office the Reagan administration asked for letters of resignation from thousands of persons appointed by former President Carter, Schedule C personnel and noncareer members of the Senior Executive Service. Those letters now are being reviewed at departments and the White House, and most of the letter-writers will be out of jobs within the next few weeks.

On Monday, Energy notified 15 of its noncareer SES staffers that they were to clear out by Tuesday at close of business. Twelve of the Schedule C (political and confidential aides) employes also left yesterday. The fate of sex remaining noncareer SES members and 13 Schedule C people at Energy now is being reviewed at the White House.

Department of Energy is the only major federal operation -- so far -- to freeze promotions, but insiders say it could happen in other agencies, pending an evaluation of jobs and personnel slated for upgrading.

Commerce Department says most of the 140 Schedule C people, and its 50 noncareer SES officials, still are on the job. About 12 Schedule C people already have left and the status of those who remain, and the noncareer SES people, is being reviewed this week.

Department of Transportation has kept about a third of its 60 Schedule C employes on as consultants, helping their successors. Many political types at the department got letters a week ago Monday advising them that their resignations had been accepted, effective last Friday.

Only eight of Treasury's 24 top political appointees are still around, and about half of the department's 60 noncareer SES and Schedule C people remain.

The political director and deputy director jobs at the Office of Personnel management are being filled temporarily by career employes, until they find out who their new leaders will be. Half a dozen people are said to be under consideration for the jobs, but the White House appears in no hurry to fill them. It is relying, instead, on the Office of Management and Budget to handle the federal hiring freeze, work up the new Reagan budget and deal in personnel matters with federal agencies.