Special arrangements have been made to ease the impact of high fuel costs related to the coal miner's strike on Potomac Edison Co. customers which will appear for the first time in bills going out this week.

With its coal supplies down, the utility had to buy some more expensive electricity from neighboring power companies. It normally generates power at a cost of 1 to 1 1/2 cents for each kilowatt hour, but has been buying as much as 60 percent of its power from other utilities at 4 1/2 to 5 1/2 cents for each kilowatt hour. Potomac Edison's 240,000 customers in Maryland, Virginia and West Virginia will ultimately have to foot the bill, but not all at once.

The tab for Maryland residents served by Potomac Edison, including a section of upper Montgomery of the fuel adjustment section of the bill, according to officials of both the utility and the Maryland Public Utilities Commission. However, the 125,000 customers in the Maryland service area can request a payment plan that will spread the payments out over the next 12 months.

"We had this plan before for large users but are putting it in now for small users, residential customers," said Potomac Edison president John McCardell. For example, a customer with an electrically heated home who is billed in March for a two-month usage of 3,700 kilowatt hours normally would pay $80 in the fuel adjustment section alone of his bill. The fuel section of his March bill will be $160. If the customer chooses the spread-out payment plan, however, the fuel adjustment part of the bill will be $105, still 50 percent higher than normal.

In Virginia, all of Potomac Edison's 55,000 customers will be assessed an additional 4.4 mills (or just under onehalf cent) per kilowatt hour for the next six months, and West Virginians will pay an extra 2 mills for the coming year. McCardell said the only difference among the three plans was that Maryland's system puts all the costs on those who used the electricity, while Virginia and Maryland ratepayers who use little winter power but air condition their homes will be paying the surcharge during the summer, in effect shouldering some of their neighbors' expenses.