The Reagan administration, saying the United States "intends to maintain a solid international reputation as a reliable supplier of coal," unveiled its long-awaited coal export policy yesterday.

The policy calls for increased private involvement in port development and shipping projects, user fees for shippers and a relaxation of regulations that the administration believes delay channel dredging and impede the movement of coal from mines to ports.

Also yesterday, the administration presented its general national energy plan, in which it restated its intentions to allow market forces to shape domestic energy use.

J. Hunter Chiles, director of the Energy Department's Office of Policy, planning and Analysis, said the administration's energy plan differs from other proposals by not relying on reducing oil imports as the major basis for the national energy program. Rather, key elements are domestic economic development and helping the United States to become a reliable trading partner, Chiles said.

Commerce Secretary Malcolm Baldrige said yesterday that the coal policy is based on the idea that the government should expedite, rather than subsidize, coal exports and bring about "greater American participation in the international coal trade" by removing "government impediments to the achievement of that goal."

Delay has become a major cost factor in the U.S. coal export business, both in port construction and shipping. Under federal regulations, for example, domestic waterway dredging projects now take up to 25 years to complete. Balridge said yesterday, as critics of that process have said before him, that so much time for waterway dredging is uncceptable.

"We don't have 25 years to wait. We should be making progress in the next decade if we're going to take advantage of the opportunity" presented by the United States' 475 billion tons of coal reserves, about one-fourth of the world's total coal deposits, Baldrige said.

He said the administration has proposed legislation "to allow justifiable" dredging projects to be under taken -- using the world "justifiable" as a signal that the administration will not entertain development requests from port authorities that are little affected by the burgeoning coal trade.

Where new port construction is needed to accommodate the increasingly large colliers used by coal importers, the administration proposes "expedited planning and engineering" by the Army Corps of Engineers. The Reagan group hopes to speed the process by transferring responsibility for technical review of water projects from the Water Resources Council to the Office of Management and Budget.

That action may be opposed by environmental groups, but the administration said in its policy statement that the transfer would "allow a less cumbersome and faster review process for most water projects, including coal port proposals." Coal Policy Highlights

Aid foreign investment and encourage private financing of coal export projects.

Relax surface mining and leasing regulations.

Support channel-deepening projects.

Work through Congress to provide rail shippers greater price stability.

Initiate a coal export promotion program under the Commerce Department.