President Reagan fulfills a campaign promise by pressing ahead with dismantling the Department of Energy. But he happens to do so just when three major studies are focusing on energy as a key to international economy and security - and just when rising gasoline prices and possibly even spot shortages are likely to remind Americans of the subject in simple dollars and cents. Also , only yesterday the International Energy Agency's annual meeting in Paris reaffirmed that, despite current oil availability, there is no room for complacency about conservation and developing alternative sources.
Unfortunately, Mr. Reagan risks conveying an impression of such complacency when he appears to diminish the US commitment to energy symbolized by DOE. This department was set up in the aftershock of the Arab oil embargoes and in recognition of the need for strong US energy policy to meet present demands and future emergencies. It has been criticized for excessive bureaucracy, though, to be fair, much of its personnel and resources are devoted to the nuclear weapons that were made part of its domain. It is not immune to the federal economizing necessary today.
But Congress will have to consider carefully whether to accept the White House's proposal to get rid of the Energy Department and bury its surviving functions in other departments. The White House argues for leaving energy more to the marketplace, and the marketplace can do much. But the transfer to other agencies offers no advantages, according to someone who knows both economics and energy such as Prof. Robert Stobaugh of the Harvard Business School, though it has the disadvantage of playing down what should still be a national priority.
To avoid sending the wrong signal, Mr. Reagan could follow up on the concern expressed in yesterday's message to Congress even while criticizing federal regulation and subsidy. Such concern would only be enhanced by the studies mentioned earlier:
* From Georgetown University's Center for Strategic and International Studies , which often produces materials supportive of Reagan policies, comes ''The Critical Link: Energy and National Security in the l980s.'' With a send-off by Henry Kissinger, it spells out ways to rapidly reduce US dependence on imported oil through encouragements to production, conservation, and such basics as improved refinery technology. The results would not only help the US in any future cut-offs but release more oil for other countries.
* From the energy research team of Amory and Hunter Lovins comes ''Brittle Power: Energy Strategy for National Security.'' It seeks to achieve energy ''resilience'' as a safeguard against sabotage, technical breakdown, or natural calamity. The means include decentralization, community preparations, use of appropriate renewable sources - not every renewable is always appropriate, they warn. They argue that alternatives like solar energy can make it in the marketplace - if the marketplace is not distorted by subsidies to other fuels.
* From Harvard energy expert Daniel Yergin and other authors will come (next month) the results of a lengthy international study by several organizations: ''Global Insecurity,'' offering plans for energy and economic revival. Mr. Yergin notes that Americans often forget a prime cause of today's economic distress is the oil crisis of the 1970s. It brought both economic downturn and inflation. He says high interest rates discourage the private sector from taking the risks of research and development in energy that are essential to America's future. Therefore government subsidy remains necessary.
Mr. Reagan seemed to acknowledge this yesterday, at least in relation to high-risk, long-term research. He also took account of protecting the public interest against supply disruptions through maintaining an oil reserve contingency plan.
But can the US sustain the requisite commitment to energy without a Department of Energy? Mr. Reagan will have to convince Congress the answer is yes if it is to help him fulfill that campaign promise.