California, home of the ever-filled freeway, the three-car family and smog, may be where President Carter's energy conservation program faces its stiffest test.

Officials here, reacting to the President's energy message to Congress, pointed out today that two of the program's major components - conversion of oil and natural gas burning facilities to coal and the increased gasoline tax - would affect California more than any other state.

Whether these proposals can be worked out here could determine how effective the Carter energy could determine how effective the Carter energy plan is going to be elsewhere in the nation. Federal and state officials will sit down with state utility and industry executives Friday in San Francisco to hold the first major meeting in the nation on implementing the President's proposals since he outlined them Wednesday.

Unofficial estimates, which state officials said today appear preliminary but reasonable, indicate that Southern California could end up paying as much as $3.5 billion in increased energy prices by 1985 because of the Carter proposals.

The state air quality problem now forces many industries and utilities to burn imported Indonesian crude oil, which has a low sulphur content but sells for nearly $15 a barrel, well above oil prices in the rest of the country.

California has no coal-burning utilities and virtually unliveable, said Thomas Quinn, head of the state's Air Resources Board.

"San Francisco would be unpleasant if we shifted to coal," said Quinn. "It would probably be as bad as Los Angeles is today. But the effect of conversion to coal on Los Angeles would be disastrous. We'd probably have to shut down our outdoor school athletic program altogether because of the quality of the air."

Quinn and other state officials predicted today that unless some type of techological breakthrough can be achieved before the President's 1985 coal conversion deadline California would have to be granted some type of exemption.

State officials recently went over their coal conversion problem with members of the Carter administration. They claim the only places coal-fired power plants could go without violating federal air pollution standards would be either in the remote desert, where not enough water exists to run such plants, or on the equally remote northern coast, where no rail lines exist to carry coal to power plants.

The President's gasoline-saving proposal will also hit hardest here in a state which owns 12.5 per cent of all the cars in the United States and consumes 10 per cent of the nation's gasoline.

Richard Maullin, head of the state Energy Resources Conservation and Development Commission, generally praised the Persident's energy plan today, but said it would place an unfair share of the proposed gasoline tax burden on California drivers.

Maullin said a Rand Corp. study commissioned recently by the state showed that as a result of long-distance commuting necessitated by southern California's widespread population, gasoling price increases would not measurably affect consumption in the state.

Another key element in the President's gasoline conservation plan is a shift by drivers to smaller automobiles which consume less fuel. But Californians already purchase small cars in far greater numbers than the rest of Americans do - nearly 60 per cent of the state's 1976 car purchases were small or compact autos, as opposed to 48 per cent for the rest of the country.