GLOSSARY OF ELECTRIC UTILITY TERMS
AVERAGE ANNUAL KWH USE PER CUSTOMER - Annual kilowatt-hour sales of a class of service (see CLASSES OF ELECTRIC SERVICE for list) divided by the average number of customers for the same 12-month period (usually refers to all residential customers, including those with electric space heating). A customer with two or more meters at the same location because of special services, such as water heating, etc., is counted as one customer.
BTU (BRITISH THERMAL UNIT) - The standard unit for measuring quantity of heat energy, such as the
heat content of fuel.
It is the
Content of Fuel, Average - The heat value per unit quantity of fuel expressed in BTU as determined from tests of fuel samples. Examples: BTU per pound of coal, per gallon of oil, etc.
BTU PER KILOWATT-HOUR - See HEAT RATE.
CAPABILITY - The maximum load which a generating unit, generating station, or other electrical apparatus can carry under specified conditions for a given period of time, without exceeding approved limits of temperature and stress.
Gross System - The net generating station capability of a system at a stated period of time (usually at the time of the system's maximum load), plus capability available at such time from other sources through firm power contracts.
The Florida Electric Power Coordinating Group and much of the utility industry prefer a different definition. Their use of the words relates to the capability at the generator terminals and would therefore be defined as the "total capability of a system's generating units measured at their terminals."
Margin of Reserve - See CAPABILITY MARGIN.
Net Generating Station - The capability of a generating station as demonstrated by determined by actual operating experience less power generated and used for auxiliaries
Capability may vary with the character of the
water temperatures characteristic causes.
in thermal Capability
stations or availability of is sometimes referred to as
load, time water in Effective
of year (due to hydro stations), Rating.
test or as and other circulating and other
Net System - The net generating station capability of a system at a stated period of time (usually at the time of the system's maximum load), plus capability available at such time from other sources through firm power contracts less firm power obligations at such time to other companies or systems.
Peaking - Generating capability normally designed for use during the maximum load period of a
designated time interval.
CAPABILITY MARGIN / RESERVE MARGIN and system maximum load requirements (peak load)
The difference between net system capability
It is the margin of capability available to provide
for scheduled maintenance, emergency outages, system operating requirements, and unforeseen loads.