The Fermi II nuclear power plant went into commercial production at Monroe, Mich., 18 years after construction began, clearing the way for Detroit Edison Co. to begin charging its customers for the $4.5-billion plant. The plant was running at 94% of capacity and generating 1,024 megawatts of electricity when it completed a 100-hour, nonstop test. Edison Chairman Walter J. McCarthy Jr. said that Fermi II heralds a rebirth of the U.S. nuclear power industry. Final testing of the plant was supposed to have taken six months but it took 2 1/2 years. The average Detroit Edison residential customer's bill will increase about $1.10 a month while the company recovers its construction costs.