The House Commerce Committee yesterday approved one of the major pieces of President Carter's energy program, standby gasoline rationing authority for the president.

The plan is expected to go to the House floor next week.

Though the president made standby rationing authority part of his Sunday night address to the nation, a House Commerce subcommittee had already drafted and approved such a plan.

The full committee worked late last night on the proposal because energy subcommittee Chairman John D. Dingell (D-Mich.) said the panel wants to move along to a bill providing "fast-track" approval of energy projects such as synthetic fuel, another item in the Carter package.

It is not clear, however, whether the bill will have the sweeping authoirity that the president proposed for his Energy Mobilization Board.

The gas rationing proposal accepted by the committee yesterday differs from the plan rejected by the full House in May. It eliminates the requirement that the president submit a detailed rationing plan at the time he receives standby authority.

Under the new proposal, the president would be given standby rationing authority without having to submit a plan at the same time. Instead, he would have to report on his progress in developing a plan within 90 days of enactment of the bill, and submit the detailed plan 60 days before he intended to impose rationing. Congress then would have 15 days to review it, and either house could veto it.

Included is a requirement that, before rationing can be imposed, there be a 20 percent shortfall in petroleum product supplies for more than 30 days, or anticipation of such a shortage.

An attempt to kill the new rationing proposal lost, 18 to 4. A move to lower the threshold from a 20 percent shortfall to 15 percent failed twice, by 22 to 11 and by voice vote.

An effort to eliminate the threshold and give the president wide flexibility in imposing rationing lost, 24 to 8.

"I think it's essential the American people understand we're not voting on rationing," said Rep. Phil Gramm (D-Tex.). He called gas rationing "expensive, inequitable and inefficient" and said a 20 percent trigger would assure the American people that the rationing was needed and that the benefit would outweigh the cost.

Rep. Richard Ottinger (D-N.Y.) argued the "utter chaos" of gas lines and shortages had occurred at a much lower shortfall, less than 10 percent, and said people would rather have rationing than long gas lines and higher prices.

But Dingell said elimination of the 20 percent trigger would "kill the bill" and destroy "the fragile coalition" put together to win approval of standby rationing.

Rep. Barbara Mikulski (D-Md.) had an amendment adopted that strongly urges Carter to rationing coupons among households on the basis of the number of licensed drivers rather than number of cars, as previously proposed.

The rationing proposal was attached to a bill passed by the Senate that would allow the president to set fuel conservation targets for each state and would permit the governors to adopt plans to meet those tragets. The president would also draw up a federal conservation plan that could be imposed on a state only if it failed to meet the targets.

The House committee adopted the conservation bill by voice vote.

A commerce subcommittee added a triger to this portion of the bill, requiring a 10 percent shortage in petroleum supplies before the conversation measures could go into effect.

Republicans complained that the conservation bill would give sweeping authority to the states to impose any measures they wished.

The bill would permit, but not mandate, a sticker plan for the president and the governors to use, in which cars could not be driven one day of the week.

It also would permit the establishment of minimum gas purchases while prohibiting weekend station closings.

The Senate bill does not contain a standby rationing plan, but a House Senate conference could approve the House version or the Senate could adopt its own separately.