Generation (Electricity):
The process of producing electric energy by transforming other
forms of energy; also, the amount of electric energy produced,
expressed in watthours (Wh).
Gross Generation:
The total amount of electric energy
produced by the generating units at a generating station or
stations, measured at the generator terminals.
Net Generation:
Gross generation less the electric
energy consumed at the generating station for station use.
Generator:
A machine that converts mechanical energy into electrical energy.
Generator Nameplate Capacity:
The full-load continuous rating of a generator, prime mover, or
other electric power production equipment under specific
conditions as designated by the manufacturer. Installed generator
nameplate rating is usually indicated on a nameplate physically
attached to the generator.
Geothermal Plant:
A plant in which the prime mover is a steam turbine. The
turbine is driven either by steam produced from hot water or by
natural steam that derives its energy from heat found in rocks or
fluids at various depths beneath the surface of the earth. The
energy is extracted by drilling and/or pumping.
Gigawatt (GW):
One billion watts.
Gigawatthour (GWh):
One billion watthours.
Greenhouse Effect:
The increasing mean global surface temperature of the earth
caused by gases in the atmosphere (including carbon dioxide, methane,
nitrous oxide, ozone, and chlorofluorocarbon). The greenhouse
effect allows solar radiation to penetrate but absorbs the infrared
radiation returning to space.
Grid:
The layout of an electrical distribution system.
Gross Generation:
The total amount of electric energy produced by a generating
facility, as measured at the generator terminals.
Heavy Oil:
The fuel oils remaining after the lighter oils have been
distilled off during the refining process. Except for start-up and
flame stabilization, virtually all petroleum used in steam plants
is heavy oil.
Hydroelectric Plant:
A plant in which the turbine generators are driven by falling
water.
Industrial:
The industrial sector is generally defined as manufacturing,
construction, mining agriculture, fishing and forestry establishments
Standard Industrial Classification (SIC) codes 01-39. The utility
may classify industrial service using the SIC codes, or based on
demand or annual usage exceeding some specified limit. The limit
may be set by the utility based on the rate schedule of the utility.
Intermediate Load (Electric System):
The range from base load to a point between base load and peak.
This point may be the midpoint, a percent of the peakload, or the
load over a specified time period.
Internal Combustion Plant:
A plant in which the prime mover is an internal combustion
engine. An internal combustion engine has one or more cylinders
in which the process of combustion takes place, converting energy
released from the rapid burning of a fuel-air mixture into
mechanical energy. Diesel or gas-fired engines are the principal
types used in electric plants. The plant is usually operated
during periods of high demand for electricity.
Interruptible Gas:
Gas sold to customers with a provision that permits curtailment
or cessation of service at the discretion of the distributing
company under certain circumstances, as specified in the service
contract.
Interruptible Load:
Refers to program activities that, in accordance with contractual
arrangements, can interrupt consumer load at times of seasonal peak
load by direct control of the utility system operator or by action of
the consumer at the direct request of the system operator. It
usually involves commercial and industrial consumers. In some
instances the load reduction may be affected by direct action of the
system operator (remote tripping) after notice to the consumer in
accordance with contractual provisions. For example, loads that can
be interrupted to fulfill planning or operation reserve requirements
should be reported as Interruptible Load. Interruptible Load as
defined here excludes Direct Load Control and Other Load Management.
(Interruptible Load, as reported here, is synonymous with
Interruptible Demand reported to the North American Electric
Reliability Council on the voluntary Office of Energy Emergency
Operations Form OE-411, :q.Coordinated Regional Bulk Power Supply
Program Report,:eq. with the exception that annual peakload effects
are reported on the Form EIA-861 and seasonal (i.e., summer and
winter) peakload effects are reported on the OE-411).
Kilowatt (kW):
One thousand watts.
Kilowatthour (kWh):
One thousand watthours.
Light Oil:
Lighter fuel oils distilled off during the refining process.
Virtually all petroleum used in internal combustion and
gas-turbine engines is light oil.
Lignite:
A brownish-black coal of low rank with high inherent moisture and
volatile matter (used almost exclusively for electric power
generation). It is also referred to as brown coal. Comprises two
groups classified according to the following ASTM Specification
D388-84 for calorific values on a moist material-matter-free basis:
Limits Btu/lb.
GE LT
Lignite A 6300 8300
Lignite B - 6300
Load (Electric):
The amount of electric power delivered or required at any
specific point or points on a system. The requirement originates
at the energy-consuming equipment of the consumers.
Maximum Demand:
The greatest of all demands of the load that has occurred within
a specified period of time.
Mcf:
One thousand cubic feet.
Megawatt (MW):
One million watts.
Megawatthour (MWh):
One million watthours.
MMcf:
One million cubic feet.
Natural Gas:
A naturally occurring mixture of hydrocarbon and nonhydrocarbon
gases found in porous geological formations beneath the earth's
surface, often in association with petroleum. The principal
constituent is methane.
Net Capability:
The maximum load-carrying ability of the equipment, exclusive of
station use, under specified conditions for a given time interval,
independent of the characteristics of the load. (Capability is
determined by design characteristics, physical conditions, adequacy
of prime mover, energy supply, and operating limitations such as
cooling and circulating water supply and temperature, headwater and
tailwater elevations, and electrical use.)
Net Generation:
Gross generation minus plant use from all electric utility owned
plants. The energy required for pumping at a pumped-storage plant is
regarded as plant use and must be deducted from the gross generation.
Net Summer Capability:
The steady hourly output, which generating equipment is expected
to supply to system load exclusive of auxiliary power, as
demonstrated by tests at the time of summer peak demand.
Net Winter Capability:
The steady hourly output which generating equipment is expected
to supply to system load exclusive of auxiliary power, as
demonstrated by tests at the time of winter peak demand.
Noncoincidental Peak Load:
The sum of two or more peakloads on individual systems that do
not occur in the same time interval. Meaningful only when
considering loads within a limited period of time, such as a day,
week, month, a heating or cooling season, and usually for not more
than 1 year.
Non-Firm Power:
Power or power-producing capacity supplied or available under
a commitment having limited or no assured availability.
Nonutility Power Producer:
A corporation, person, agency, authority, or other legal entity
or instrumentality that owns electric generating capacity and is not
an electric utility. Nonutility power producers include qualifying
cogenerators, qualifying small power producers, and other nonutility
generators (including independent power producers) without a
designated franchised service area, and which do not file forms
listed in the Code of Federal Regulations, Title 18, Part 141.
Nuclear Fuel:
Fissionable materials that have been enriched to such a
composition that, when placed in a nuclear reactor, will support a
self-sustaining fission chain reaction, producing heat in a
controlled manner for process use.
Nuclear Power Plant
A facility in which heat produced in a reactor by the fissioning
of nuclear fuel is used to drive a steam turbine.
Off-Peak Gas:
Gas that is to be delivered and taken on demand when demand
is not at its peak.
Ohm:
The unit of measurement of electrical resistance. The
resistance of a circuit in which a potential difference of 1 volt
produces a current of 1 ampere.
Operable Nuclear Unit:
A nuclear unit is "operable" after it completes low-power
testing and is granted authorization to operate at full power.
This occurs when it receives its full power amendment to its
operating license from the Nuclear Regulatory Commission.
Outage:
The period during which a generating unit, transmission line, or
other facility is out of service.
Peak Demand:
The maximum load during a specified period of time.
Peak Load Plant:
A plant usually housing old, low-efficiency steam units; gas
turbines; diesels; or pumped-storage hydroelectric equipment
normally used during the peak-load periods.
Peaking Capacity:
Capacity of generating equipment normally reserved for operation
during the hours of highest daily, weekly, or seasonal loads. Some
generating equipment may be operated at certain times as peaking
capacity and at other times to serve loads on an around-the-clock
basis.
Percent Difference:
The relative change in a quantity over a specified time period.
It is calculated as follows&colon. the current value has the previous
value subtracted from it; this new number is divided by the absolute
value of the previous value; then this new number is multiplied by
100.
Petroleum:
A mixture of hydrocarbons existing in the liquid state found in
natural underground reservoirs, often associated with gas. Petroleum
includes fuel oil No. 2, No. 4, No. 5, No. 6; topped crude;
Kerosene; and jet fuel.
Petroleum Coke:
See Coke (Petroleum).
Petroleum (Crude Oil):
A naturally occurring, oily, flammable liquid composed
principally of hydrocarbons. Crude oil is occasionally found in
springs or pools but usually is drilled from wells beneath
the earth's surface.
Planned Generator:
A proposal by a company to install electric generating equipment
at an existing or planned facility or site. The proposal is based on
the owner having obtained (1) all environmental and regulatory
approvals, (2) a signed contract for the electric energy, or (3)
financial closure for the facility.
Plant:
A facility at which are located prime movers, electric
generators, and auxiliary equipment for converting mechanical,
chemical, and/or nuclear energy into electric energy. A plant may
contain more than one type of prime mover. Electric utility
plants exclude facilities that satisfy the definition of a qualifying
facility under the Public Utility Regulatory Policies Act of 1978.
Plant Use:
The electric energy used in the operation of a plant. Included
in this definition is the energy required for pumping at
pumped-storage plants.
Plant-Use Electricity:
The electric energy used in the operation of a plant. This
energy total is subtracted from the gross energy production of the
plant; for reporting purposes the plant energy production is then
reported as a net figure. The energy required for pumping at
pumped-storage plants is, by definition, subtracted, and the energy
production for these plants is then reported as a net figure.
Power:
The rate at which energy is transferred. Electrical energy
is usually measured in watts. Also used for a measurement of
capacity.
Power Pool:
An association of two or more interconnected electric systems
having an agreement to coordinate operations and planning for
improved reliability and efficiencies.
Price:
The amount of money or consideration-in-kind for which a
service is bought, sold, or offered for sale.
Prime Mover:
The engine, turbine, water wheel, or similar machine that drives
an electric generator; or, for reporting purposes, a device that
converts energy to electricity directly (e.g., photovoltaic solar and
fuel cell(s)).
Profit:
The income remaining after all business expenses are paid.
Public Authority Service to Public Authorities:
Public authority service includes electricity supplied and
services rendered to municipalities or divisions or agencies of
State or Federal governments, under special contracts or agreements
or service classifications applicable only to public authorities.
Public Street and Highway Lighting:
Public street and highway lighting includes electricity supplied
and services rendered for the purposes of lighting streets, highways,
parks, and other public places; or for traffic or other signal system
service, for municipalities, or other divisions or agencies of State
or Federal governments.
Pumped-Storage Hydroelectric Plant:
A plant that usually generates electric energy during peak-load
periods by using water previously pumped into an elevated storage
reservoir during off-peak periods when excess generating capacity is
available to do so. When additional generating capacity is needed,
the water can be released from the reservoir through a conduit to
turbine generators located in a power plant at a lower level.
Purchased Power Adjustment:
A clause in a rate schedule that provides for adjustments to the
bill when energy from another electric system is acquired and it
varies from a specified unit base amount.
Pure Pumped-Storage Hydroelectric Plant:
A plant that produces power only from water that has previously
been pumped to an upper reservoir.
Qualifying Facility (QF):
A cogeneration or small power production facility that meets
certain ownership, operating, and efficiency criteria established
by the Federal Energy Regulatory Commission (FERC) pursuant to the
Public Utility Regulatory Policies Act (PURPA). (See the Code of
Federal Regulations, Title 18, Part 292.)
Part 292.
Railroad and Railway Services:
Railroad and railway services include electricity supplied and
services rendered to railroads and interurban and street railways,
for general railroad use, including the propulsion of cars or
locomotives, where such electricity is supplied under separate and
distinct rate schedules.
Rate Base:
The value of property upon which a utility is permitted to earn a
specified rate of return as established by a regulatory authority.
The rate base generally represents the value of property used by the
utility in providing service and may be calculated by any one or a
combination of the following accounting methods&colon. fair value, prudent
investment, reproduction cost, or original cost. Depending on which
method is used, the rate base includes cash, working capital,
materials and supplies, and deductions for accumulated provisions for
depreciation, contributions in aid of construction, customer advances
for construction, accumulated deferred income taxes, and accumulated
deferred investment tax credits.
Ratemaking Authority:
A utility commission's legal authority to fix, modify, approve,
or disapprove rates, as determined by the powers given the
commission by a State or Federal legislature.
Receipts:
Purchases of fuel.
Regulation:
The governmental function of controlling or directing economic
entities through the process of rulemaking and adjudication.
Reserve Margin (Operating):
The amount of unused available capability of an electric power
system at peakload for a utility system as a percentage of total
capability.
Residential:
The residential sector is defined as private household
establishments which consume energy primarily for space heating,
water heating, air conditioning, lighting, refrigeration, cooking
and clothes drying. The classification of an individual consumer's
account, where the use is both residential and commercial, is based
on principal use. For the residential class, do not duplicate
consumer accounts due to multiple metering for special services
(water, heating, etc.). Apartment houses are also included.
Residual Fuel Oil:
The topped crude of refinery operation, includes
No. 5 and No. 6 fuel oils as defined in ASTM Specification D396 and
Federal Specification VV-F-815C; Navy Special fuel oil as defined in
Military Specification MIL-F-859E including Amendment 2 (NATO Symbol
F-77); and Bunker C fuel oil. Residual fuel oil is used for the
production of electric power, space heating, vessel bunkering, and
various industrial purposes. Imports of residual fuel oil include
imported crude oil burned as fuel.
Restricted-Universe Census:
This is the complete enumeration of data from a specifically
defined subset of entities including, for example, those that exceed
a given level of sales or generator nameplate capacity.
Retail:
Sales covering electrical energy supplied for residential,
commercial, and industrial end-use purposes. Other small classes,
such as agriculture and street lighting, also are included in this
category.
Revenue:
The total amount of money received by a firm from sales of its
products and/or services, gains from the sales or exchange of assets,
interest and dividends earned on investments, and other increases in
the owner's equity except those arising from capital adjustments.
Running and Quick-Start Capability:
The net capability of generating units that carry load or have
quick-start capability. In general, quick-start capability
refers to generating units that can be available for load within
a 30-minute period.
Sales:
The amount of kilowatthours sold in a given period of time;
usually grouped by classes of service, such as residential,
commercial, industrial, and other. Other sales include public
street and highway lighting, other sales to public authorities
and railways, and interdepartmental sales.
Sales for Resale:
Energy supplied to other electric utilities, cooperatives,
municipalities, and Federal and State electric agencies for resale
to ultimate consumers.
Scheduled Outage:
The shutdown of a generating unit, transmission line, or other
facility, for inspection or maintenance, in accordance with an
advance schedule.
Short Ton:
A unit of weight equal to 2,000 pounds.
Small Power Producer (SPP):
Under the Public Utility Regulatory Policies Act (PURPA), a small
power production facility (or small power producer) generates
electricity using waste, renewable (water, wind and solar), or
geothermal energy as a primary energy source. Fossil fuels can be
used, but renewable resource must provide at least 75 percent of the
total energy input. (See Code of Federal Regulations, Title 18,
Part 292.)
Spinning Reserve:
That reserve generating capacity running at a zero load and
synchronized to the electric system.
Spot Purchases:
A single shipment of fuel or volumes of fuel, purchased for
delivery within 1 year. Spot purchases are often made by a user to
fulfill a certain portion of energy requirements, to meet
unanticipated energy needs, or to take advantage of low-fuel prices.
Stability:
The property of a system or element by virtue of which its
output will ultimately attain a steady state. The amount of power
that can be transferred from one machine to another following a
disturbance. The stability of a power system is its ability
to develop restoring forces equal to or greater than the
disturbing forces so as to maintain a state of equilibrium.
Standard Industrial Classification (SIC):
A set of codes developed by the Office of Management and Budget,
which categorizes business into groups with similar economic
activities.
Standby Facility:
A facility that supports a utility system and is generally
running under no-load. It is available to replace or supplement
a facility normally in service.
Standby Service:
Support service that is available, as needed, to supplement a
consumer, a utility system, or to another utility if a schedule or
an agreement authorizes the transaction. The service is not
regularly used.
Steam-Electric Plant (Conventional):
A plant in which the prime mover is a steam turbine. The steam
used to drive the turbine is produced in a boiler where fossil fuels
are burned.
Stocks:
A supply of fuel accumulated for future use. This includes
coal and fuel oil stocks at the plant site, in coal cars, tanks,
or barges at the plant site, or at separate storage sites.
Subbituminous Coal:
Subbituminous coal, or black lignite, is dull black and generally
contains 20 to 30 percent moisture. The heat content of subbituminous
coal ranges from 16 to 24 million Btu per ton as received and
averages about 18 million Btu per ton. Subbituminous coal, mined
in the western coal fields, is used for generating electricity
and space heating.
Substation:
Facility equipment that switches, changes, or regulates
electric voltage.
Sulfur:
One of the elements present in varying quantities in coal which
contributes to environmental degradation when coal is burned. In
terms of sulfur content by weight, coal is generally classified as
low (less than or equal to 1 percent), medium (greater than 1
percent and less than or equal to 3 percent), and high (greater than
3 percent). Sulfur content is measured as a percent by weight of
coal on an :q.as received:eq. or a :q.dry:eq. (moisture-free, usually
part of a laboratory analysis) basis.
Switching Station:
Facility equipment used to tie together two or more electric
circuits through switches. The switches are selectively arranged
to permit a circuit to be disconnected, or to change the electric
connection between the circuits.
System (Electric):
Physically connected generation, transmission, and distribution
facilities operated as an integrated unit under one central
management, or operating supervision.
Transformer:
An electrical device for changing the voltage of alternating
current.
Transmission:
The movement or transfer of electric energy over an
interconnected group of lines and associated equipment between points
of supply and points at which it is transformed for delivery to
consumers, or is delivered to other electric systems. Transmission
is considered to end when the energy is transformed for distribution
to the consumer.
Transmission System (Electric):
An interconnected group of electric transmission lines and
associated equipment for moving or transferring electric energy in
bulk between points of supply and points at which it is transformed
for delivery over the distribution system lines to consumers, or is
delivered to other electric systems.
Turbine:
A machine for generating rotary mechanical power from the energy
of a stream of fluid (such as water, steam, or hot gas). Turbines
convert the kinetic energy of fluids to mechanical energy through
the principles of impulse and reaction, or a mixture of the two.
Uniform System of Accounts:
Prescribed financial rules and regulations established by the
Federal Energy Regulatory Commission for utilities subject to its
jurisdiction under the authority granted by the Federal Power Act.
Useful Thermal Output:
The thermal energy made available for use in any industrial or
commercial process, or used in any heating or cooling application,
i.e., total thermal energy made available for processes and
applications other than electrical generation.
Voltage Reduction:
Any intentional reduction of system voltage by 3 percent
or greater for reasons of maintaining the continuity of service of
the bulk electric power supply system.
Watt:
The electrical unit of power. The rate of energy transfer
equivalent to 1 ampere flowing under a pressure of 1 volt at
unity power factor.
Watthour (Wh):
An electrical energy unit of measure equal to 1 watt of power
supplied to, or taken from, an electric circuit steadily for 1 hour.
Wheeling Service:
The movement of electricity from one system to another over
transmission facilities of intervening systems. Wheeling service
contracts can be established between two or more systems.
Wholesale Sales:
Energy supplied to other electric utilities, cooperatives,
municipals, and Federal and State electric agencies for resale to
ultimate consumers.
