Electric system reliability has two components – adequacy and security.

  • Adequacy is the ability to meet the total aggregated electric demand and energy requirements of customers at all times, irrespective of scheduled and unscheduled outages of electric generation facilities.
  • Security is the ability of the electric system to withstand sudden disturbances, such as electric short circuits or unanticipated loss of system facilities.
[SourceThe Potential Benefits of Distributed Generation and Rate-Related Issues That May Impede Their Expansion, U.S. Department of Energy, February 2007, p.xxi]