AMIDST ALL the hirings and firings, one good new appointment got lost to view. This was the surprise announcement that Dennis Hayes, a prominent advocate of solar energy, will become head of the government's Solar Energy Research Institute in Golden, Colo.

There are several things worth noting here. One is Mr. Hayes's exceptional qualification for the job. As director of Solar Lobby, the group that has spearheaded the drive for a bigger role for solar power, he has earned a reputation for political skill and technical soundness. The research institute he will head was created two years ago in the hope that it would become the nation's leading center for solar research. So far it has failed to do so.Mr. Hayes's appointment gives it another chance.

The appointment also provides an opportunity to lavish some rare paise on the Department of Energy. Mr. Hayes's selection was the work of Secretary James Schlesinger and Undersecretary John Deutch. Mr. Schlesinger has been charged so often with being "anti-solar" that the allegation has become routine -- and routinely accepted. His decision to appoint Mr. Hayes should diminish the distrust that has marked the relationship between DOE and the proponents of solar power. If solar and renewable resources are to fulfill the presient's goal of providing 20 percent of the nation's power by the turn of the century -- a shaky proposition in any case -- a much more mature spirit of cooperation will have to exist between the two.

For the moment, the Institute at Golden is not going to be able to produce miracles. Of the $600 million or $700 million in federal research and development funds for solar energy, it gets only about $90 miliion, and the director is sharply circumscribed in how he can allocate even that sum. Perhaps if the Institute, under Mr. Hayes, begins to produce good results, Congress should consider channeling more of the fractionated solar budget through it. Before that, however, there is a lot of bureaucratic and administrative housecleaning to be done. Finally, there is the question of whether Mr. Hayes will be able to attract top-flight scientific talent. One way to Congress could help would be to elevate the Golden center to the status of a national laboratory. The names -- Oak Ridge, Brookhaven, Argonne and the rest -- mean something big and important and magnetic in the scientific community. This is one case in which there is something in a name.