The Federal Energy Regulatory Commission (FERC) is considering action that could force electrical utilities to offer from $5 million to $10 million in consumer refunds for alleged overcharges during last year's coal strike, sources say.

An executive session meeting of the five-member FERC yesterday began consideration of a staff investigation of utility billing procedures and suspected overcharges during the December 1977 to March 1978 labor dispute.

The investigation of wholesale purchases and sales of power by the utilities during the nation's longest coal strike found that, "There may have been some improprieties in the billing of power and pass-through of costs in fuel-adjustment clauses."

A FERC staff member, Howard Foreman, goes further, saying, "There were abuses as far as the fuel clause goes." Foreman, however, stresses that the amounts involved "on a customer-by-customer basis may not be very large."

This view is shared by the staff investigation which said the possible overcharges "did not add significantly to the cost of electricity to consumers."

FERC officials say that the commission next week will determine whether further review of the electrical utilities' wholesale purchases is necessary and whether to take steps that could letad to consumer refunds.

To prevent recurrences of possible overcharges, the FERC staff investigation recommended that the commission require utilities to file rate schedules and billing arrangements to be used during emergencies. In addition the FERC report called for companies that had incorrectly billed customers for wholesale purchases under "fuel-adjustment clauses" to provide refunds if necessary.

The FERC investigation resulted from a directive issued by the commission after the coal strike last year.

The staff found that, during the strike, the rates charged for wholesale electric power ranged from $10 to $60 per megawatt hour.

The major focus of the FERC investigation was on utilities in the Pennsylvania-New Jersey-Maryland Interconnection, the Allegeny Power System and the American Electric Power Corp., each groups of affiliated companies or members of a power pool that buy and sell power to each other.

The staff report on the FERC investigation did not include any specific findings about the companies that provide retail electrical power service to the Washington metropolitan area.