DR. JAMES B. EDWARDS, the departing secretary of energy, bade farewell to Washington last week. He will be remembered here for a degree of cheery incompetence that, with the best will in the world, no successor is likely to equal. The White House has seemed to like incompetence in that job. It has not yet announced the appointment of a replacement.

Dr. Edwards' single visible interest, as secretary, was the promotion of nuclear energy. That was the great exception to all the Reaganish rhetoric about the wrongheadedness of subsidies and the evil of government intervention. But he leaves the nuclear cause in far worse condition than he found it. By his loud advocacy of fuel reprocessing and the breeder reactor, he gave new emphasis to all the most dangerous and least useful aspects of nuclear technology, greatly strengthening the political opposition to it.

Dr. Edwards did not manage to abolish the Department of Energy, as he had hoped. But he did succeed in encouraging most of its ablest people to find employment elsewhere. One of his last acts was to force out Maxine Savitz, the deputy assistant secretary for conservation. In Dr. Edwards' view, energy conservation is not a proper concern of government.

He did not see why the United States needs any active energy policy at all, or any active people to run it. He did not see why soaring oil prices disrupt the economies of the industrial democracies, raising inflation, unemployment and industrial distress. He did not see why all that should, in any case, be a concern of the government. There is much that Dr. Edwards did not see.

His own energy policy was to look on the sunny side of things, hope for the best, and extend best wishes for long life and continued tenure to the present regime in Saudi Arabia. The energy crisis, he confidently assured his fellow Americans last week, is behind them. That's true -- in the sense that they are temporarily ahead of it. But if they look back, they will see that it seems to be gaining on them.