A designation ,created by the Public Utility Regulatory Policies Act of 1978 (PURPA), for non-utility power producers that meet certain operating, efficiency and fuel use standards set by the Federal Energy Regulatory Commission. To receive status as a qualifying facility (OF) under PURPA, the facility must produce electric energy and "another form of useful thermal energy through the sequential use of energy," and meet certain ownership, operating, and efficiency criteria established by the Federal Energy Regulatory Commission (FERC). (See the Code of Federal Regulations, Title 18. Part 292.) OFs may rely on renewable energy sources or cogeneration.