Power generation capacity used to serve an essentially constant level of customer demand. Baseload generating units typically operate whenever they are available, and they generally have a capacity factor that is above 60%. Base Load Capacity is often served by nuclear, coal or efficient combined cycle power plants.  [SourceThe Potential Benefits of Distributed Generation and Rate-Related Issues That May Impede Their Expansion, U.S. Department of Energy, February 2007, p.xiv.]