Wayne State University plans to leave Thermal L.L.C.'s steam supply and build its own boiler plants, issuing $46.2 million in bonds for a project it says will help control energy costs and save money. The university is Detroit Thermal's second-largest customer, after the Detroit Medical Center. Detroit Thermal says Wayne State provided about $7 million of its $50.2 million in 2004 revenue. "We think we can generate at a cheaper price. So from a financial standpoint, why wouldn\'t we?\" said John Davis, Wayne State CFO and vice president of finance and facilities management.