President Carter, taking his more forceful speaking style on the road for the first time, said today that his new energy plan will cost $142 billion over the next decade but is worth the investment because "our freedom is beyond price."

Obviously buoyed by the initial reaction to his nationally televised energy speech Sunday night, Carter provided some details of his energy plan and a pep talk about its importance to 4,000 people at the annual convention of the National Association of Counties here.

Clenching his fist for emphasis and almost shouting at times, the president was rewarded by an enthusiastic reception from the crowd, which stood and cheered when he asked, "I want to know, will you help me succeed?"

The details of his plan for "energy independence" by 1990, however, contained a number of controversial proposals that are bound to receive a less enthusiastic reception when submitted to Congress.

The key to financing the massive investment Carter called for is the administration's proposed "windfall profits" tax on the oil industry, which has already passed the House. White House officials here said the tax should produce between $146 billion and $270 billion between now and 1990, depending on how rapidly world oil prices rise.

The president today also asked Congress to make the tax permanent. Under the House-passed version of the legislation, the tax would end in 1990.

The largest component in the Carter program, accounting for more than half the $142 billion price tag, is a proposed "Energy Security Corp." that would invest $88 billion over the next decade in projects to develop synthetic fuels. The money would include $5 billion that would be raised by the sale of small denomination "Energy Bonds."

The president pledged to invest another $16.5 billion in improvements to mass transit systems, $3.5 billion for his earlier solar energy proposals and $9 billion in a variety of grants, loans and tax credits to encourage conservation and increase production, including $5 billion in grants and loans to assist public utilities to comply with a proposed mandatory 50 percent reduction in their use of oil.

Carter also said he will ask Congress to provide $2.4 billion a year in grants - a total of $24 billion over the next decade - to cushion low-income Americans against the effects of higher energy prices.

The key elements or the program hinge on congressional action, and the president today announced only a limited number of steps he could take on his own.

He said he is ordering the immediate decontrol of the price of so-called "heavy oil," an action that administration officials estimated will raise the price of this type oil from $6 a barrel to about $18 a barrel.

"Heavy oil" is so named because it is thicker and contains more impurities than conventional oil. It requires additional refining and is more expensive to produce. Deposits of heavy oil are more abundant than deposits of conventional oil.

He also announced that he is establishing an oil import quota of 8.2 million barrels a day for this year, with the 1980 quota expected to be about the same. Sunday night, Carter announced his intention to impose oil import quotas, pledging that the United States will never exceed the 8.5 million barrels a day it imported during the peak import year of 1977.

These actions and earlier proposals by the administration, officials said, should reduce U.S. oil imports to 5 million barrels a day or less by 1990.

The stakes in achieving that goal, the president told his audience in Kansas City's H. Roe Bartle convention center, are very high. "Today," he said, "not only our economy, but our very independence is threatened" by dependence on imported oil.

Later, in Detroit, Carter said that if the economy falters significantly in the months ahead, he would support a tax cut and said he favored starting with payroll taxes.

Passage of major portions of the ambitious program are far from certain. There is, for example, widespread opposition among environmentalists to the kind of massive investment in synethic fuels that Carter proposed.

There is likely to be even stronger opposition from some quarters to another part of the Carter program - a proposed Energy Mobilization Board that would have sweeping power to ramrod energy projects deemed critical to meeting the 1990 goals through the thicket of federal, state and local laws and regulations.

It was to rally public support behind this program and his beleaguered presidency that Carter traveled to Kansas City and later today to Detroit, bringing with him the deliberately more forceful speaking style he displayed Sunday night in his extraordinary television address on the "crisis of confidence" he sees afflicting the country.

So often soft-spoken to the point of reticence in public appearances before large gatherings, it was a different Jimmy Carter who appeared in Kansas City today, almost shouting at times and gesturing frequently. He touched on some of the same themes that made up the bulk of his speech Sunday, and added two elements that had been noticeably lacking in the address from the Oval office.

Reviving the anti-oil company rhetoric he used when he first proposed the "windfall profits" tax, the president said the administration in pressing oil refiners to increase production of fuels.

"If they do not cooperate voluntarily," he said, "we will not hesitate to use the authority that I have to require the oil companies to meet the basic energy needs of our nation.

"The oil companies must cooperate," he added in a hoarse shout as the crowd cheered.

Carter critics, among them California Gov. Edmund G. (Jerry) Brown Jr., had noted that the Sunday speech made no mention of nuclear energy. Today, Carter answered that criticism, reaffirming his faith in atomic power. The presidential commission studying the Three Mile Island accident should help to improve safety measures, he said, adding that "nuclear power must play an important role in the United States to ensure our energy future."

In Detroit later today, the president's reception from members of the Communications Workers of American was even more enthusiastic than in Kansas City. And Carter, his strained voice showing the signs of wear from the earlier speech, responded in kind. Brimming with self confidence, he shed his suit coat and rolled up his sleeves, laughing and joking with many of his questioners.

Declaring that only he as president has the "one clear voice in this country on a sustained basis" Carter recalled the words of one one visitor to the Camp David summit who told him he was "so bogged down in managing the government you can't lead the nation."

"I listened to that and I learned my lesson," he added.

Several of the questions dealt with the administration's 5.5 per cent wage guideline. The president made no commitments, but said the wage and price guidelines are under review and promised they would be "fair."

For Carter, today's trip marked the beginning of the most critical period of his presidency, a test of whether his rallying cry about energy and vow to restructure his tepid style of leadership can reverse his decline in popularity that threatens his chances of relection.

The impact of his speech Sunday, and all the drama and mystery of the Camp David "domestic summit conference" that preceded it, clearly had its intended effect initially. An unusually large press contingent followed the president today, and the three commercial television networks broadcast the speech from Kansas City live.

White House officials were cheered by these developments. En route to Kansas City, Democratic National Committee Chairman John White told reporters on Air Force One, "We're feeling pretty good. I took down my 'for sale' sign this morning."

In his speech, Carter invoked the main theme of his television address Sunday, asserting that Americans can use the challenge of energy shortages to reunite and overcome a "crisis of confidence" in the nation's future.

"Just as the energy shortage has forced us to face our deepest fears and divisions, so our goal of an energy-secure American will help us to rebuild our strength and our confidence as a people," he said. "We are coming to understand that the reasons for our energy crisis go beyond gas lines and wasteful habits, to a loss of confidence that divides us and threatens us and which, for years, too many years, has prevented presidents and the Congress and a great nation from acting courageously to meet this energy challenge."

Carter added:

"That is why we must decide here and now that we can and will regroup, we can and will unite, we can and will restore our confidence, we can and will win the battle to solve our energy problems and restore our nation's security and keep us strong."

The president also briefly mentioned the economy near the end of his speech, pledging to "hold steady" to his goal of a balanced budget without promising to achieve that goal. He said he will "not hesitate to take action to avoid a serious recession," but gave no hint of what such action might entail.

In the midst of the presidential rhetoric, White House officials issued an optimistic assessment of the nation's gasoline and home heating oil situation They said oil imports have averaged 6.4 million barrels a day for the last five weeks, from a low of less than 6 million barrels a day in May, allowing refineries to increase production that should ease the summer gasoline shortage

The United States also imports about 1.9 million barrels a day of refined oil products.

The officials also predicted that the higher level of imports should allow refiners to meet the administration goal of a 240-million-barrel stockpile of home heating oil fuel by October.

Following the president's speech, White House officials provided additional details on the energy proposals Among them:

Energy Security Corp.: conceived as an independent government quasigovernmental entity, the corporation would spur the development of synthetic fuels with $88 billion for a limited number of government-run fuel plants, plus price guarantees, purchase agreements, direct loans and loan guarantees to energy firms.

The corporation, with an estimated $50 million a year in operating expenses that would have to be appropriated, would be run by a seven-member board - four appointed by the president, plus the secretaries of energy, treasury and one other department. Its employes would be exempt from civil service regulations.

Energy Mobilization Board: a second new government entity that Carter will ask Congress to create, the board would have authority to designate nonnuclear energy projects as "critical" to meeting the 1990 oil import goal and to establish binding schedules for federal, state and local government decisions affecting such projects.

If government at any level failed to keep the schedule, the board would have power to make the decisions itself and, subject to a presidential veto, to waive procedural requirements affecting such an energy project.

Residential and commercial conservation: Carter proposed a $2 billion program over 10 years to reduce the amount of oil used for heating and cooling. Included in this is a proposed mandatory provision requiring utilities to offer long term loans for conservation improvements to owners of homes and commercial buildings heated and cooled by gas or electricity. The utilities could include the loans in their rate bases, but the loan principal would not have to be repaid until the building was sold.

Utility fuel conversion: Under Carter's proposal, public utilities would be granted "tickets" from the government granting them the right to burn a limited amount of oil to generate power. The goal of the program is to reduce utility oil use by 50 percent by 1990, with the government offering $5 billion in grants and loan guarantees as an incentive to convert to other fuels. CAPTION: Picture, The president in Kansas City: "I want to know, will you help me succeed?" UPI