The terms defined below are
intended to provide background on a selected group of terms and concepts useful
in the L.R. 455 Study.
The contracted right to use an electrical system
to transfer electrical energy. Under a competitive market system, state and
federal regulators are expected to require this access at fixed, regulated
A charge levied on a power supplier, or a
consumer, for access to a utility's transmission or distribution system. This
charge may include a "stranded cost' or other charges as well as transmission or
distribution service charges. (See Wires Charge).
Any entity that seeks to aggregate consumers for delivery
of service under specified contract terms.
Interconnected operations services
for operating reserve, voltage control, regulation and frequency response,
scheduling and system control and dispatch, and other power supply necessary to
effect a reliable transfer of electrical energy at specified contract terms
between a buyer and a seller.
A measure of time that a generating unit or
transmission line, or other facility is capable of providing service, whether or
not it is actually in service. Typically this measure is expressed as a percent
available for the period under consideration.
Power provided by contract to a customer
when that customer's normal source of power is not available.
The minimum amount of power delivered or demanded over a
given period at a constant rate. On a energy demand chart this will be the
constant bottom line demand for a given customer or group of customers. (This is
differentiated from Intermediate and Peak demand).
A direct contract between a power
producer or end-user outside of a centralized power pool or POOLCO.
The rated continuous load-carrying ability, expressed in
megawatts (MW) or megavolt-amperes (MVA) of generation, transmission, or other
electrical equipment. For generating plants, capacity is typically
differentiated into "Baseload Capacity" (a capacity factor above 60 percent);
"Intermediate Capacity" (a capacity factor of 20 to 60 percent); and "Peaking
Capacity" (a capacity factor of less than 20 percent).
The ratio of total energy generated by
a plant for a specified period of time to the maximum possible energy it could
have generated if operated at the maximum capacity rating for the same period,
expressed as a percent.
Production of electricity from steam, heat, or
other forms of energy produced as a by-product of another process-usually
A specific contiguous electrical path
from a point of receipt to a point of delivery for which transmission rights
have been contracted. (The "contract path" is a convenient fiction because
electricity does not necessarily flow from point A to point B.)
An electric system or systems, bounded by
interconnection metering and telemetry, capable of controlling generation to
maintain its interchange schedule with other Control Areas and contributing to
frequency regulation of the Interconnection.
The right of a transmission provider to interrupt
all or part of a transmission service due to constraints that reduce the
capability of the transmission network to provide that transmission service.
Transmission service is to be curtailed only in cases where system reliability
is threatened or emergency conditions exist.
The rate at which electric energy is delivered to or by a
system, generally expressed in kilowatts or megawatts, at a given instant or
averaged over any designated interval of time. Demand should not be confused
The highest electric requirement occurring in a given
period (e.g., an hour, a day, month, season, or year). For an electric system,
it is equal to the sum of the metered net outputs of all generators within a
system and the metered line flows into the system, less the metered line flows
out of the system.
The sum of two or more demands that
occur in the same demand interval.
The sum of two or more demands that
occur in different demand intervals.
The amount of capacity that a supplier
agrees to make available for delivery to a particular entity and which the
entity agrees to purchase.
That portion of the Contract Demand that a power supplier
is obligated to provide except when system reliability is threatened or during
This is a term that is intended to
cover all activities undertaken by an electric supplier or consumers to
influence the amount and timing of electricity use. This may occur through
technological improvements, or revision in practices, billing rates, or direct
control measures by the supplier (e.g. "smart metering" or non-firm or
interruptible load agreements).
Any owner of a distribution system and
associated substations and other facilities providing use of the distribution
system to suppliers and end-users. The distribution provider in a competitive
market will also be the likely supplier of metering, billing and other
administrative services related to direct consumer contact.
Distribution lines, poles, meters and associated
facilities that deliver energy directly to the end-use customer.
The allocation of demand to
individual generating units on line to effect the most economical production of
The generation or use of electric power over a period of time expressed in kilowatthours (kWh), megawatthouse (MWh), or gigawatthours (GWh). There are several types of electrical energy:
Electrical energy supported by sufficient
capacity, interruptible only on conditions agreed upon by contract. To guarantee
firm energy, the seller will provide all ancillary services.
Electrical energy that may be
interrupted either by the provider or the receiver by giving notice to the other
party as specified in a contract.
Electrical energy supplied during a period of high system
demand as specified in a contract.
Electrical energy supplied during a
period of relatively low system demand as specified in a contract.
Total electric energy losses in the
electric system consisting of transmission, transformation, and distribution
system losses between supply and delivery points.
Measures undertaken as part of
Demand-Side Management to reduce the consumption of electricity for a specific
task or function.
Energy Services Company
An entity offering consumers a range of
energy efficiency measures designed to reduce consumption and costs.
Predicted demand for electric power for a given customer or
group of customers for a given period. A forecast may be short-term (e.g., 15
minutes) for system operation purposes, or five to ten years for a contract
period, or twenty years for generating planning purposes. The forecast will
typically include identification of baseload, intermediate, and peak demand
based upon historical sales and projected growth data.
The franchise is a grant of right or privilege to occupy or
use public streets and ways and facilities located on public streets and ways to
deliver service to consumers. Franchises are historically, and typically,
granted by local governments.
The process of producing
electrical energy from other forms of energy; also the amount of electric energy
produced, usually expressed in kilowatthours (kWh) or megawatthours (MWh). Gross
generation is the electrical output at the terminals of the generator, usually
expressed in megawatts (MW). Net generation is gross generation minus the
service power requirements of the generating station itself
A condition in which the generation and demand or
interchange schedules do not match.
An independent power producer (IPP)
refers to any entity that owns or operates and electric generating facility that
is not included in a utility's rate base. This term included utility
subsidiaries as well as entrepreneurs and non-utility producers.
An independent system operator
is envisioned by federal regulators and others to be an independent third party
who will take over ownership and/or control of a region' 5 transmission system
for the purpose of providing open access to retail and wholesale markets for
supply. (This is to be distinguished from a Regional Transmission Group or RTG
which is a group of transmission line owners who propose to cooperatively
operate the regional transmission grid.)
A planning process for new energy
resources that evaluates the nil range of alternatives, including new generating
capacity, power purchases, energy conservation and efficiency measures,
cogeneration and district heating and cooling applications, and renewable energy
resources, in order to provide adequate and reliable service to customers at the
lowest system cost.
An end-use device or customer that receives power from an
electrical system. Load should not be confused with Demand, which is a measure
of the power that a load receives or requires.
A nonchronological, graph summary of
demand levels with corresponding time durations using a curve, which plots
demand magnitude (power) on one axis and percent of time that the magnitude
occurs on the other axis.
An electric system's process of
regulating its generation to follow the changes in its customers' demand. This
capability is especially important for firm power and delivery of
A measure of the degree of uniformity of demand over a
period of time, usually one year, equivalent to the ratio of the average demand
expressed as a percentage. It is calculated by dividing the total energy
provided by a system during the period by the product of the peak demand during
the period and the number of hours in the period. This is expressed as a
percentage (e.g., residential load factors are typically 45-55 percent).
The process and methods of utilizing devices to measure the
amount and direction of electrical energy flow; particularly for end-use.
Open Access Same Time
Information Sharing (OASIS):
information posting system for transmission access data that allows all
transmission customers to view the data simultaneously. Development of the OASIS
system has been mandated by federal regulators as on one the necessary
components of a open transmission system.
There are two primary types of outages:
The removal from service availability
of a generating unit, transmission line, or other facility for emergency reasons
or a condition in which the equipment is unavailable due to unanticipated
Removing equipment from service availability for
inspection and/or general overhaul of major equipment. A planned outage does not
usually result in power supply failure, although planned outages during critical
peak demand periods may place stress upon a system and lead to load shedding or
A point on the electrical systems,
usually a substation, where a power supplier delivers electricity to the
distribution system. This point can also include an interconnection with another
system. The Point of Delivery is specified in a supply contract.
Generating plants in any given region are interconnected
through a transmission grid. The operation of this grid and its coordination and
cooperation between generating plant owners takes place on a formal "tight pool"
basis with coordinated dispatch (e.g., the New England Power Pool), or as a
"loose pool" with less formal integration and coordination.
POOLCO or Power
An entity envisioned by federal
regulators and other that would provide a centrally dispatched spot market power
pool. It would make ancillary generation services available to all market
participants on comparable terms. The POOLCO or Power Exchange is sometimes seen
as the alternative to "Bilateral Contracts".
A power broker is an entity that
arranges a transaction between a buyer and a seller. The broker does not take
title to the power.
A power marketer is an entity that buys and sells
power. The marketer does take title to the power. A marketer may or may not own
A power supplier is a term that can
include both Power Brokers and Power Marketers.
Regional Transmission Group (RTG):
A voluntary organization of
transmission owners and users interested in coordinating transmission planning
and expansion on a regional basis.
The degree to which an electrical system can deliver power supplies to customers at contract specifications, or acceptable regulatory standards. Reliability may be measured by the frequency, duration, and magnitude of adverse effects on the electric supply. It is usually considered for two primary elements:
adequacy of supply and security of
Renewable energy generally refers to
energy derived from non-fossil fuel resources (excluding nuclear). It often
includes wind, photovoltaics, biomass and hydro. However, the definition may
vary in different states or regions of the county and in situations in which new
energy technology development is being promoted (e.g., hydro may be excluded).
There are several types of reserve capability and capacity that are usually included in consideration of supply of firm power needs. These include:
operating reserve, spinning reserve, regulating
reserve, contingency reserve, nonspinning reserve, and planning reserve.
Public interest programs and goals
which could be compromised or abandoned by a competitive retail market for
Above-market costs of utilities and
other power producers that would be "stranded" by consumers choosing a different
The revenues, taxes, and fees for
federal, state, and local governments that would be lost by changes in
contracts, valuations and revenue policies
An individual at an electric system
control center whose responsibility it is to monitor and control that electric
system in real time.
Any transmission line owner who
provides use of the facilities for the transfer of electrical energy.
An interconnected group of lines and associated
equipment for the movement or transfer of electric energy between points of
supply and points at which it is transformed for delivery to customers, or is
delivered to other electric systems. Transmission is commonly on the generator
side of the substation (distribution is on the customer side.)
The control of transmission voltage
through adjustments in generator reactive output and transformer taps, and by
switching capacitors and inductors on the transmission and distribution systems.
Restructuring of utilities into component operations:
generation, transmission and distribution. Also
"unbundling" of consumer bills into price components reflecting charges for each
segment of operation.
The contracted use of electrical facilities of one or more
entities to transmit electricity for another entity. When conducted on behalf of
retail customers it is sometimes referred to a "retail wheeling."
A term that refers to all charges added
to distribution and transmission charges. (See Access Charge).