Combined heat and power (CHP) is a specific form of distributed generation (DG) that refers to the placement of electric-power-generating units at or near customer facilities to supply on-site energy needs. CHP enhances DG’s advantages by the simultaneous production of thermal and power output, thus increasing overall efficiency. Once available only to large commercial buildings and urban areas, CHP systems — sometimes referred to as “cogeneration” — are now produced on a scale that’s safe, practical and affordable to homeowners.