A cost that cannot be avoided by reducing output because the cost was incurred previously, such as the original cost of an asset (less depreciation, but including the operating and maintenance expenses and all taxes)
the rate in cycles per second (Hertz) at which voltage and current oscillate in electrical power systems (the reference frequency is 60 Hz in North America)
The difference between net capacity (a system's total capacity resources) and net internal demand, that is generally expressed in MW for operating reserves and as a percentage of either system load or installed generating capacity for planning reserves
The difference between scheduled and real power flows on a transmission path, assuming zero inadvertent interchange (also called loop flow, unscheduled power flow, or circulating power flow)
Under PURPA, a non-utility generator of electric power that has received a certificate from FERC, enabling it to sell electricity only at wholesale avoided cost to a utility
Wholesale electricity pricing that is determined separately by zone, based on the supply and demand in a region, and uses locational marginal pricing (LMP)
The interconnected operations service that provides the needed capacity and energy to transmission customers to replace the loss of generation and to cover the portion of demand that exceeds generation supplies for more than a short period
