AS A POLITICAL challenge to President Carter, Gov. Jerry Brown's energy plans for California are decidedly interesting. But as assurance of one of life's necessities to the nation's most populous state, the governor's plans are exceedingly risky.

The governor favors solar energy and disapproves of nuclear reactors. But Californians are as attached to their cars and their air conditioning as anyone else, and solar energy is not going to pick up much of the load in the decade immediately ahead. The governor and his administration have evidently conceded the point and are talking in terms of large coal-fired generators to replace the reactors that are being vetoed. But concentrations of coal-burning power stations create dangerous air pollution anywhere, let alone in the peculiar climatic conditions of California. Most of the elements in the governor's prescription are attractive enough, taken one by one. It's the process of trying to fit them together that raises doubts.

The Carter energy program, still stuck in Congress, tried to strike a balance. It would have enforced conservation by raising fuel prices, but it would also have expanded reliance on coal and nuclear power. As our correspondent Lou Cannon observed the other day, Gov. Brown seems particularly anxious to make it clear to everyone that he is hostile to nuclear power on principle, while Mr. Carter is not. Regarding conservation, Mr. Brown enthusiastically supports it but does not get very specific. The state could, of course, discourage driving by pushing up the tax on gasoline, as the president bravely but unsuccessfully tried to do. We do not recollect any move by Mr. Brown in that direction.

One of the curiosities of energy politics, now illustrated once again in California, is the common tendency of people to see nuclear reactors as infinitely more threatening than coal-burning plants. It is quite true that a serious nuclear accident, although unlikely, could have catastrophic effects. But it is equally true that people die every day in this country of the effects of breathing air laden with the pollutants that roar out of a coal-fired generator's stacks. Statisticians debate the precise numbers, but the toll certainly runs to some thousands of people every year. It is curious, is it not, that California should consider that alternative preferable? The argument is that California vigilanty enforces its air-quality standard. But it is far from certain that those standards are consistent with coal generators big enough to replace the nuclear reactors that the utilities had planned for the next decade.

California and the Southwest generally constitute a great and valuable laboratory for energy development. A favorable climate means that solar energy will be easier to introduce there than in colder and grayer places. It is also easier to introduce new technologies in regions where population is growing rapidly, just as it is easier to build a solar house from scratch than to convert old houses in established neighborhoods. But developing significant amounts of solar power at reasonable prices is going to be slow and difficult anywhere - while banning reactors is always quick and easy.

That disparity wouldn't make much difference if this country were prepared to accept intermittent power shortages and dim-outs.But it isn't. Any state that runs short of electricity can expect an overwhelming public demand for the fastest possible remedy. As the utilities have pointed out, the fastest possible remedy would be generators fueled with diesel oil. With that, the country would come full circle - for, if you remember, it was the attempt to reduce oil imports that started Americans thinking seriously about energy plans in the first place.