The report was prepared as part of the Ohio River Basin Energy Study (ORBES), a multidisciplinary policy research program. The ORBES region consists of all of Kentucky, most of West Virginia, substantial parts of Illinois, Indiana, and Ohio, and southwestern Pennsylvania. The inventory lists installed electrical generating capacity in commercial service as of December 1, 1976, and scheduled capacity additions and removals between 1977 and 1986 in the six ORBES states (Illinois, Indiana, Kentucky, Ohio, Pennsylvania, and West Virginia). The following information is included for each electrical generating unit: unit ID code, company index, whether joint or industrial ownership, plant name, whether inside or outside the ORBES region, FIPS county code, type of unit, size in megawatts, type of megawatt rating, status of unit, date of commercial operation (actual or scheduled), scheduled retirement date (if any), primary fuel, alternate fuel, type of cooling, source of cooling water, and source of information.