The chairman of a congressional watchdog committee yesterday accused the Department of Energy of withholding an internal memorandum indicating that under current leaded gasoline phase-out plans, "significant gasoline shortages could develop in 1980, with or without controls."

In a letter hand-delivered to Deputy Secretary John F. O'Leary, Rep. John Moss (D-Calif.), chairman of the House Oversight and Investigations subcommittee, sharply criticized the department for withholding the memo - which never left the draft stage - during congressional questioning over DOE efforts to end price controls on gasoline.

"I am becoming more and more convinced," Moss wrote, "that the issue is no longer just gasoline decontrol, but the competence and credibility of the Department of Energy.

"Gasoline is currently in ample supply. But as you know, the Department of Energy is in possession in information that points to a potential critical gasoline shortage in 1980, greater even than the 280,000 barrel a day gasoline shortage that resulted from the 1973 Arab Oil Embargo."

The internal memo predicts the possibility of a 400,000 barrel per day shortage by 1980. In the past, DOE spokesmen have said only that no shortages were foreseen thru 1979.

"A 400,000 barrel per day shortage of gasoline in 1980, as based on DOE's own internal forecast," Moss wrote, "will increase the price of gasoline, in the absence of controls, by an estimated 20-40 cents per gallon, $20-40 billion a year, while raising the spectre of a possible national emergency."

The critical portion of the memo was written by Doug Robinson, Assistant Administrator for Regulatory and Emergency Planning.

"The memo was prepared for Bardin's David Bardin, administrator of the economic Regulatory Administration) signature in the event that a decision was made by DOE to recommend gasoline decontrol to Congress, but was never sent," Robinson said in an interview yesterday. It was, however, given to Moss' staff.

DOE was on the verge of recommending to Congress that gasoline prices be decontrolled about a month ago, but the plan was postponed when the Environmental Protection Agency and several environmental groups balked, claiming that the price of unleaded gasoline would soar, and many motorists would thus ignore laws mandating they use unleaded gas. Such a situation would result in a worsening air pollution problem, the environmentalist warned.

The DOE is now soliciting opinions on whether or not it should now do an Environmental IMPACT Study on its plans to decontrol gas.

While Robinson says DOE is confident there will be no gasoline supply problems in 1979, "the 1980 figures we have were very preliminary. We didn't send that memo because there was a lot of dispute within the agency over the assumptions used, especially on the amount of refinery capacity that will be available at that time and the level of imports predicted. In addition we know that the supply can be increased dramatically by shaving the octane levels."

But still, Robinson added, "In my personal opinion, if the EPA takes the most rigid position on MMT and Lead phasedowns, it is possible that we could have some supply problem in 1980, although data from some refiners suggests otherwise. It's still an open question."