Washington's politicians and citizens are bracing themselves for President Carter's television appearance tonight with a mixture of great expectations, pessimism, and gasoline crisis-induced anxiety.

Local officials and residents interviewed yesterday said the president could satisfy them only with a policy-setting address on energy and economic problems. And there were plenty of ideas - and advice - on what Carter could say.

"It will be a major disappointment to my constituents if Carter doesn't make some bold and dramatic commitments to new directions in energy policy," said Rep. Michael Barnes (D-Md.). "He should indicate that it's time that we finally recognized that this is the moral equivalent of war."

"I think the country is looking for a clear statement of where we are going," said Montgomery County Executive Charles W. Gilchrist. "Carter has to have a grasp of what is needed and he has to state it in a way the country can understand."

James Waters of Rockville, interviewed as he watched a soap-box derby in the District of Columbia, said, "I don't know what he'll say. I hope he says gas will be cheaper and more plentiful. But not only that, I hope I know what he's talking about, whatever he says."

Anticipation of Carter's speech has reached such a level that District Mayor Marion Barry, Maryland Gov. Harry Hughes and Virginia Gov. John N. Dalton issued an unusual joint statement yesterday, describing how Carter's expected call for the new energy solutions could be implemented in the area.

The statement called for passage of legislation that would "assure completion of the Metro system." Such a step would "substantially relieve our dependence on shrinking petroleum supplies," their statement said.

"We were anticipating what the president would say,"; said District Transportation Chief Douglas Schneider of the unusual statement. "We wanted to remind the community - and particularly the people who are going to vote on this Metro bill - that here is an opportunity to put some of the president's exhortations into action."

Not all of the area's political leaders were as positive about Carter's speech. "I feel strongly that he needs to reverse a lot of his policies, like oil decontrol," said Rep. Herbert E. Harris (D-Va.). "But I dont have much hope that that will happen."

#I think the speech will be window-dressing," said Susanna Cristophane, the mayor of Bladensburg. "I just think he's trying to make the public believe in what he's done, and I don't think it is going to work. He won't be able to do anything until he can negotiate with the oil business."

There were a myriad of energy poli-cies that local officials said Carter should adopt. "He should say that we should commit ourselves to a Manhattan project or a space program for energy needs," Barnes said, referring to the massive federal project that led to the development of the atomic bomb.

Barnes said the new program should include development of solar power, utility rate reform, taxes on gasoline-guzzling automobiles, a standby rationing plan, and new Energy Department leadership that "will Harris predicted that carter would call for the development 0f synthetic fuel and for measures to hold down retail prices, but added, "He's going to be shoveling against the tide in that effort."

Rep. Joseph Fisher (D-Va.), one of the few local officials to meet with Carter at Camp David, said he "half hoped and half expected" that Carter would "emphasize - strongly - conservation, because we can do more quickly that way in the next couple of years than we can any other way."

And Christian Sinclair of Mount Rainier said he had a few questions he would like Carter to answer: "Will inflation stop? Will our sons stop being killed overseas? Will blacks get more jobs?"