Coal and nuclear-generated electricity is enabling Ohio Edison Co. to loosen up the rusted joints of Midwest industry without even a drop of oil.

The Akron, Ohio-based utility sold 33 percent more power in the first three months of 1988 than in the same quarter last year.While the steel and auto industries in Ohio and western Pennsylvania demanded 16.7 percent more power last quarter than a year ago, Ohio Edison also is selling more power than ever to outside utilities, underselling oil- fired electricity.

Ohio Edison officials credit the drop in the value of the U.S. dollar with reviving much of Ohio's heavy industry.

The service territory for Ohio Edison and its subsidiary, Pennsylvania Power Co., New Castle, Pa., covers the industrial region of northeast Ohio and portions of western Pennsylvania.

Steel companies in the region are running near or at full capacity, said H. Peter Burg, Ohio Edison financial vice president

Pittsburgh-based USX Corp., Dallas-based LTV Corp. and Marion, Ohio-based Marion Steel Co. are some of the major companies that have mills in Ohio Edison's territory. USX is back in full gear after a strike last year, Mr. Burg said.

Steel companies bought 17 percent of Ohio Edison's retail electric sales in the region in 1987.

Car and truck manufacturers also are using more power than before. General Motors Corp., Detroit, Ford Motor Co., Dearborn, Mich., and particularly the Chicago-based truck maker Navistar International Corp. have shown tremendous turn-arounds since the dollar has fallen, he said.

Meanwhile, commercial and residential sales continue to grow at about 6 percent a year, according to figures current through the first quarter of 1988.

Coal prices have fallen consistently for the last five years, from a little over $39 a ton to about $33.50 a ton, enabling Ohio Ed to produce cheaper power than many East Coast oil-fired utilities.

Ohio Edison generates 87.4 percent of its power from coal, the rest from nuclear plants.

Off-system sales, primarily to the Mid-Atlantic region, are more than twice what they were a year ago. Ohio Edison sold some 2.7 million megawatt hours to Mid-Atlantic states during the first quarter, up 149.4 percent from a year earlier.

Much of the increase was due to a new 450-megawatt sales contract with Potomac Electric Power Co., Washington, D.C., Mr. Burg said.

Additionally, oil prices for Eastern utilities are higher this year than last, meaning much greater sales on the spot electricity market, Mr. Burg said. The Pennsylvania-New Jersey-Maryland Interconnection, a group of 12 utilities in those states, still buys slightly more than half of Ohio Edison's outside sales.