The terms defined below are intended to provide background on a
selected group of terms and concepts useful in the L.R. 455 Study.
Access: 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 prices.
Access Charge: A charge levied on a power supplier or a consumer for
access to a utilityís transmission or distribution system. This charge
may include a "stranded costí or other charges as well as
transmission or distribution service charges. (See Wires Charge).
Aggregator: Any entity that seeks to aggregate consumers for delivery
of service under specified contract terms.
Ancillary Services: 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.
Availability: 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.
Backup Power: Power provided by contract to a customer when that
customerís normal source of power is not available.
Baseload: The minimum amount of power delivered or demanded over a
given period at a constant rate. On an 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).
Bilateral Contract: A direct contract between a power producer or
end-user outside of a centralized power pool or POOLCO.
Capacity: 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).
Capacity Factor: 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.
Co-generation: Production of electricity from steam, heat or other
forms of energy produced as a by-product of another process - usually
Contract Path: 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.)
Control Area: 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.
Curtailability: 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.
Demand: 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 with Load.
Peak Demand: 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.
Coincident Demand: The sum of two or more demands that occur in the
same demand interval.
Noncoincident Demand: The sum of two or more demands that occur in
different demand intervals.
Contract Demand: The amount of capacity that a supplier agrees to
make available for delivery to a particular entity and which the entity
agrees to purchaser
Firm Demand: That portion of the Contract Demand that a power
supplier is obligated to provide except when system reliability is
threatened or during emergency conditions.
Demand-Side Management: 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).
Distribution Provider (DISCO): 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 meeting,
billing and other administrative services related to direct consumer
Distribution System: Distribution lines, poles, meters and associated
facilities that deliver energy directly to the end-use customer.
Economic Dispatch: The allocation of demand to individual generating
units on line to effect the most economical production of electricity.
Electrical Energy: The generation or use of electric power over a
period of time expressed in kilowatt-hours (kWh), megawatt-hours (NM) or
gigawatt-hours (GWh). There are several types of electrical energy:
Firm 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.
Nonfirm Energy: 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.
Peak Energy: Electrical energy supplied during a period of high
system demand as specified in a contract.
Off-Peak Energy: Electrical energy supplied during a period of
relatively low system demand as specified in a contract.
Electric System Losses: Total electric energy losses in the electric
system consisting of transmission, transformation and distribution system
losses between supply and delivery points.
Energy Efficiency: Measures undertaken as part of Demand-Side
Management to reduce the consumption of electricity for a specific task or
Energy Services Company (ESCO): An entity offering consumers a range of
energy efficiency measures designed to reduce consumption and costs.
Forecast: 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, 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.
Franchise: 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.
Generation (Electricity). The process of producing electrical energy
from other forms of energy, also the amount of electric energy produced,
usually expressed in kilowatt-hours (kWh) or megawatt-hours (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.
Imbalance: A condition in which the generation and demand or
interchange schedules do not match.
Independent Power Producer: An independent power producer (IPP) refers
to any entity that owns or operates an electric generating facility that
is not included in a utilityís rate base. This term included utility
subsidiaries as well as entrepreneurs and non-utility producers.
Independent System Operator (ISO): 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 regionís
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
proposed to cooperatively operate the regional transmission grid.)
Integrated Resource Planning: A planning process for new energy
resources that evaluates the full range of alternatives, including new
generating capacity, power purchases, energy conservation and efficiency
measures, co-generation 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.
Load: 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.
Load Duration Curve: 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.
Load Following: An electric systemís process of regulating its
generation to follow the changes in its customersí demand. This
capability is especially important for firm power and delivery of
Load Factor A measure of the degree of uniformity of demand over a
period of time, usually one year, equivalent to the ration 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
Metering: 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): An electronic
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.
Outage: There are two primary types of outages:
Forced Outage: 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
Planned Outage: 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 forced outages.
Point of Delivery: 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.
Power Pool: 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 Exchange: 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".
Power Broker: 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.
Power Marketer 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
Power Supplier: 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.
Reliability: The degree to which an electrical system can deliver power
supplies to customers at contract specifications or acceptable regulatory
standards. Reliability may be measures 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: 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 part of the county and in situations in which new energy
technology development is being promoted (e.g., hydro may be excluded).
Reserve: 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.
Stranded Benefits: Public interest programs and goals which could be
compromised or abandoned by a competitive retail market for electric
Stranded Costs: Above-market costs of utilities and other power
producers that would be "stranded" by consumers choosing a
Stranded Obligations: The revenues, taxes and fees for federal, state
and local governments that would be lost by changes in contracts,
valuations and revenue policies.
System Operator: An individual at an electric system control center
whose responsibility it is to monitor and control that electric system in
Transmission Provider: Any transmission line owner who provides use of
the facilities for the transfer of electrical energy.
Transmission System: 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).
Voltage Control: 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
Unbundling: Restructuring of utilities into component operations:
generation, transmission and distribution. Also "unbundling" of
consumer bills into price components reflecting charges for each segment
Wheeling: 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
Wires Charge: A term that refers to all charges added to distribution
and transmission charges. (See Access Charge).
Chapter One - HISTORY
Chapter Two - STRUCTURE AND
Chapter Three - STATUTORY AND
Chapter Four - PLANNING AND
Chapter Five - FINANCE AND TAX
Chapter Six - DEREGULATION AND
The Central Nebraska Public Power and
415 Lincoln Street
P.O. Box 740
Holdrege, Nebraska 68949
Phone 308-995-8601 Fax 308-995-5705