American Electric Power Co., one of the largest U.S. utilities, has dropped its plans for a huge hydroelectric power plant in Southwestern Virginia, ending five years of controversy over the $2 billion project.

The giant Ohio-based company had proposed to flood a valley known as Brumley Gap near Abingdon, Va., to build the generating station. About 100 families whose homes and farms would have been destroyed opposed the project. They were backed by the Sierra Club and other environmental groups.

This week, the utility filed a petition with the Federal Energy Regulatory Commission asking to have the project's permit withdrawn. The preliminary permit, approved last January after a protracted regulatory battle, was designed to allow the company to conduct geological and other technical studies of the site. A FERC spokesman said yesterday that the permit will probably be rescinded within 60 days if no objections are raised.

The company described its decision as part of a major cost-cutting effort, stemming from the national recession and declining electricity sales to major customers. "This was strictly a dollars-and-cents economic decision," a spokesman said yesterday. "We were just not willing to gamble the $15 million" needed to conduct the preliminary studies.

Opponents hailed the company's move as a victory. "We have been at war with the power company for five years. In the legal battle, we held them at bay," said Sam Dickenson, president of the Brumley Gap Concerned Citizens. "We're just overjoyed."

A consultants' study prepared for the opponents had described the hydroelectric project, likely to be the world's largest pumped-storage project, as "economically unsound" and "wasteful."