Electric current that reverses direction,
usually many times per second. Most electrical generators produce alternating
current.
Ampere (amp)
A measure of how much electricity is moving through a
conductor.
Blackout
A total power failure over a large area; usually caused by
the failure of major generating equipment or transmission facilities.
Bottom Ash
Slag or other residue remaining in the boiler after coal
is burned.
Brownout
A small, temporary voltage reduction implemented by a utility
to conserve electric power during periods of high use.
British Thermal Unit (Btu)
Amount of heat needed to raise the
temperature of 1 pound of water by 1 degree Fahrenheit.
Bus
An electrical conductor that serves as a common connection for two
or more electrical circuits.
Capacitor
A device that stores electrical charges and can be used to
maintain voltage levels in power lines and improve electrical-system efficiency.
Circuit
Path that electricity follows.
Circuit Breaker
A switch that opens an electric circuit when a short
occurs.
Cogeneration
Using waste heat from (1) an industry to produce
electricity, or (2) from electric utilities to produce steam for an industry or hot
water for a building.
Conductor
A material that allows an electric current to pass through it.
Also, the wire that carries electricity in an electric distribution or transmission
system.
Cycle
One complete series of changes of value of an alternating current
or an electromagnetic wave.
Demand
The amount of electricity drawn from an electric system at a given
time, measured in kilowatts.
Demand Charge
A charge for electricity based on the maximum amount of a
system's electricity a customer uses.
Demand Side Management
A utility program aimed at reducing consumer use
of energy through conservation or efficiency measures.
Deregulation
Major reduction of government oversight in a segment of
private industry.
Direct Current (DC)
Electricity that flows through a conductor in a single
direction.
Distribution Company
An electric utility that purchases wholesale power and
delivers it to customers.
Distribution System
The poles, wire and transformers used to deliver electric
energy from a bulk power supplier to the consumer.
Electric Current
A flow of electrons through a wire or other electrical
conductor. Electrons are negatively charged particles of matter.
Electric Energy
The flow of charged particles (electrons).
Electricity
Electric current or power that results from the movement of
electrons in a conductor from a negatively charged point to a positively charged point.
Electrostatic Precipitator
An electronic pollution-control device that removes
particles of fly ash from a power plant's waste gases.
Energy Efficiency Rating (EER)
A measure of how efficiently an appliance uses
energy. Determined by dividing the Btu per hour output by the number of watts used. A
higher EER means greater efficiency.
Fly Ash
Tiny solid particles of ash that escape the boiler when coal is burned;
removed by pollution-control equipment.
Fossil Fuel
Materials such as coal, oil or natural gas used to produce heat or
power; also called conventional fuels. These materials were formed in the ground millions
of years ago from plant and animal remains.
Fuel Cells
Devices that convert the chemical energy of fuels directly into
electricity.
Fuse
A protective device for electric circuits containing a wire designed to
melt and open the circuit under abnormally high electric loads.
Generation and Transmission Cooperative (G&T)
A power supply cooperative owned
by a group of distribution cooperatives. G&Ts generate power or purchase it from public or
investor-owned utilities, or from both.
Generation Plant
A plant that has generators and other equipment for producing
electricity.
Generator
A machine that converts mechanical energy into electrical energy.
Electricity is produced from magnets whirling inside coils of wire in the generator
core.
Geothermal Energy
Natural heat contained in the rocks, hot water and steam of
Earth's subsurface; can be used to generate electricity and heat homes and businesses.
Gigawatt (gw)
A measure of electric capacity equal to 1 billion watts or 1
million kilowatts.
Global Warming
A gradual warming of the Earth's atmosphere reportedly caused
by the burning of fossil fuels and industrial pollutants.
Greenhouse Gases
Carbon dioxide and other gases that reportedly contribute to
the warming of the Earth's atmosphere.
Grid System
An arrangement of power lines connecting power plants and consumers
over a large area.
Ground-Fault Circuit Interrupter (GFCI)
A device that instantly breaks the
circuit when a short develops. Required for outlets that are used in bathrooms, kitchens,
outdoors or wherever electrical equipment might come into contact with water.
Hertz (Hz)
An international measure of frequency or vibration equal to 1 cycle
per second. The alternative current frequency used in North America is 60 hertz. In Europe
and some other parts of the world it is 50 hertz.
High Voltage
Voltage in a power line higher than the 110 to 220 volts used in
most residences.
Horsepower (hp)
A measure of power equal to about 746 watts.
Hydroelectric Plant (hydro)
A facility that produces electric energy by
releasing water from a reservoir through generators.
Insulator (nonconductor)
Material that does not conduct electricity, such as
glass, ceramics or rubber. It prevents the passage of electricity. All transmission and
distribution wires are protected by insulators.
Interconnection
A tie permitting the flow of electricity between the facilities
of two electric systems.
Kilovolt (kv)
1,000 volts. The amount of electric force carried through a
high-voltage transmission line is measured in kilovolts.
Kilowatt (kW)
The basic unit of electric demand, equal to 1,000 watts; average
household demand is 10 to 20 kilowatts.
Kilowatt-hour (kWh)
A unit of energy of work equal to 1,000 watt-hours. The
basic measure of electric energy generation or use. A 100-watt light bulb burning for 10
hours uses one kilowatt-hour.
Lignite
A low-sulfur, low-energy coal, found primarily in the upper Great
Plains.
Line
A carrier of electricity on an electric power system.
Line Loss
Electric energy lost in the process of transmitting it over power
lines.
Load
The amount of electric power drawn at a specific time from an electric
system, or the total power drawn from the system. Peak load is the amount of power drawn
at the time of highest demand.
Load Factor
The ration of average demand to peak demand. It is a measure of
efficiency that indicates whether a system's electric use over a period of time is
reasonably stable or if it has extreme peaks and valleys. A high load factor usually
results in a lower average price per kilowatt-hour than a low load factor.
Megawatt (MW)
Equal to 1,000 kilowatts or 1 million watts.
Megawatt-hour (MWH)
Equal to 1,000 kilowatt-hours or 1 million watt-hours.
Meter
A device used to measure and record the amount of electricity used by
a consumer.
Nitrogen Oxides
Compounds of nitrogen and oxygen formed when fossil fuels
burn.
Nuclear Energy
Energy produced from the splitting of atoms.
Nuclear Fission
The splitting of an atomic nucleus, resulting in the release
of large amounts of energy; the basic process a nuclear reactor uses to provide heat for
the generation of electricity.
Nuclear Fusion
The combination of two light nuclei to form a heavier nucleus
with the release of some binding energy.
Nuclear Power
Electric energy generated using heat produced by an atomic
reaction.
Nuclear Radiation
Invisible particles or waves given off by radioactive
materials such as uranium.
Off-peak Power
Electricity supplied during periods of low system demand.
Ohm
The amount of resistance overcome by one volt in causing one ampere to
flow. The ohm measure resistance to current flow in electrical circuits.
Ohm's Law
Voltage equals resistance multiplied by current. In its simplest
form, Ohm's Law states that it takes one volt of pressure to push one amp of current
through one ohm of resistance.
On-line
A generating plant that is operating. When an operational plant is
not on-line, it is "down."
Outage
Interruption of service to an electric consumer because a power plant,
transmission line or other facility is not operating.
Peak Demand
The greatest demand placed on an electric system; measured in
kilowatts or megawatts; also, the time of day or season of the year when that demand
occurs.
Peak Load
The amount of electric power required by a consumer or a system
during peak demand; measured in kilowatts or megawatts.
Photovoltaics
Technology that produces electric power directly from the
sunlight. A common application is in solar-powered pocket calculators, but various
equipment remote from electric distribution lines also uses the technology.
Power
The term used for the product of voltage and current. It is measured
in watts.
Power Plant
A place where electricity is produced.
Rotor
The rotating part of a generator.
Single-phase Power
An electric circuit that consists of one alternating
current.
Slag
A residue produced by the combustion of coal. This heat-fused material
accumulates on the sides and bottom of a boiler and is removed periodically and disposed
of according to environmental regulations.
Stator
The stationary part of a generator within which a rotor turns.
Socket
A connecting place or junction for electric wires, plugs and light
bulbs.
Solar Power
Energy from the sun's radiation converted into heat or
electricity.
Static Electricity
Created when electrons "jump" from one atom to another.
You can create static electricity by rubbing certain things together, such as a brush
and your hair. Lightning is also an example of static electricity.
Substation
A place that contains transformers, which lower electricity's
voltage so that it can be used in homes and businesses.
Surge Suppressor
An electronic device that protects electric equipment from
short-term, high-voltage flows of electricity such as lightning strikes.
System Demand
The total amount of energy required to supply all customers.
Three-phase Power
An electric circuit that consists of three separate
currents delivered at one-third cycle intervals by means of a three-wire circuit;
typically used to power large industrial motors that operate at 200 volts or higher.
Transformer
A device used to raise or lower voltage in electric distribution
or transmission lines. A step-up transformer raises voltage and a step-down transformer
lowers voltage.
Transmission
The transfer of electric current from a power plant to a
destination that could be hundreds of miles away.
Turbine
A machine with blades attached to a central shaft. The pressure of
water or steam on these blades causes the turbine to spin.
Turbine Generator
The combination of a turbine and a generator working
together to produce power.
Voltage
The force which pushes electricity through a wire.
Watt
A unit of electrical power.
Wheeling
Transmitting bulk electricity from a generating plant to a
distribution system across a third system's lines.