The fifth annual economic summit began here this morning after a bitter dispute involving President Carter and French President Valery Giscard d'Estaing, with no certain prospect that they and the five other heads of government will find a way to achieve their stated goal of meaningful reduction of oil consumption.

Flanked by Secretary of State Cyrus Vance and Treasury Secretary W. Michael Blumenthal, Carter joined the leaders of Japan, France, Canada, Britain, West Germany and Italy in the first session of a two-day meeting that could have a decisive bearing on the world's economic future.

Carter told the opening session that "the eyes of the world are on his summit and how it deals with the energy crisis." He told his fellow leaders that there is "a need to be bold, specific, and substantive." The others reportedly agreed in principle that the summit must evolve a common stand to cut energy imports and consumption.

American officials stressed after the initial session that no decision taken at this summit "would solve the problem of gas lines in the United States this summer." They said the key to coping with the energy problem is to find medium-and long-term measures that will deal with energy shortages.

As the leaders started their sessions in the Akasaka Palace, the word from Geneva was that the Organization of Petroleum Exporting Countries might not agree on a uniform new oil price but is likely to split, with Saudi Arabia charging $18 a barrel and others in the cartel asking $20 to $23 or more. One report here is that Libya is holding out for $27 per barrel.

A high U.S. official said a price structure ranging from $18 to $23 a barrel would add a new inflationary thrust of at least 10 percent to the average cost of imported oil. He said he would rather see "a uniform price of $20 or $21 per barrel, with a ceiling for a period ahead." Officials fear that without a uniform price, surcharges may be added at any time.

Symbolizing the superheated atmosphere was a tart rebuttal by a White House official to critical comments by French President Giscard in a Newsweek magazine interview.

President Carter, it was said yesterday, read the interview and was angered by it. "It does not go down well," an American official said. "There is an accusatory tone in Giscard's remarks."

What enraged the Carter team was Giscard's sarcastic observation: "They haven't started," to the interviewer's comment that "the Americans have not yet succeeded in reducing consumption."

The European charge that the United States is profligate in the use of oil "is an easy explanation, a copout" a high American official said. "We have cut our consumption very substantially, as much or more in relation to gross national product as most countries in Europe."

He added that if the summit is to be a success, what is needed is less criticism "and for all of us to make a commitment to cut consumption from wherever we are."

Despite the tone of recrimination - unusual on the eve of a major summit conference - a potentially unifying factor is the knowledge that failure of the seven nations to come up with some formula cutting consumption in a way that is credible to OPEC could be a disaster.

After word of Carter's annoyance with Giscard was put out, a high American official said, "The U.S. remains determined to have a successful summit. And a successful summit would be one in which we make clear to OPEC and the rest of the world our determination to reach an agreement to cut oil consumption this year and next, expressed in quantitative terms."

Carter and Japanese Prime Minister Masayoshi Ohira, who have been in close touch on the energy question for the past three days, have rejected a five-year freeze on oil import levels through 1985 as proposed by the Common Market.

They not only fear that it would precipitate a severe economic recession, but argue that it is impossible in 1979 to foresee what the level of oil imports or consumption ought to be five years hence.

Officials say, moreover, that OPEC is more concerned about a specific and meaningful reduction in oil demand in the next few years. The United States and Japan would prefer to see country-by-country limits on oil imports, in effect, specific per-barrel import quotas as "a clear signal to OPEC that the West means business."

At his town meeting yesterday in Shimoda, Carter stressed that solution of the energy problem is the chief issue facing the seven world leaders. On his return from Shimoda, Carter met for the first time with British Prime Minister Margaret Thatcher and with Canadian Prime Minister Joe Clark.

Carter said at Shimoda that "together we must restrain and reduce our imports. Together we must reduce waste and conserve our precious energy supplies. Together we must find ways to explore and to develop alternate energy supplies and new technologies of solar power and synthetic fuels."

Yet a specific formula that would have some common element for cutting imports, and that would also take into account the "special circumstances" of individual nations is proving elusive.

Summit "preparers" for the seven nations, working on a draft communique, indicated late yesterday that there are big gaps in the language. The earlier prediction by Treasury Secretary W. Michael Blumenthal that this summit, in contrast to the others, would not be "pre-cooked" is proving to be true.

The second most important topic to be discussed at this summit is the issue of the Indochina refugees. The large and continuing flow of boat problems placing a severe burden on other Asian countries, and Carter has already said pointedly that a seven-nation position on refugees must be one of the "clear, specific and substantive decisions to the made here."

American officials were concerned today about the likely impact of a French proposal, which came as a surprise, that each of the seven nations here pledge to accept a specific percentage of refugees based on its own population.

That proposal would not cause problems for the French, the Americans or the Canadians each of whom already accepts a large number of refugees. But it is likely to be opposed by the West Germans and the Japanese, who appear willing to increase their financial support for resettlement programs but not to accept more refugees.

U.S. officials were worried that the French proposal could split the summit over the refugee issue and prevent the seven nations from agreeing on a common approach to the problem.

Energy and refugees have pushed into the background the more routine topics of prior summits, including world economic policy general North-South problems, trade and monetary issues. CAPTION: Picture, Carter and French President Giscard briefly shake hands at summit. Carter was reportedly angered by Giscard's remarks about U.S. oil consumption. AP