Here, you’ll find general definitions of frequently used terms related to New England’s wholesale electricity markets and power system.
Precise legal definitions can be found in the following documents:
10-minute nonspinning reserve (TMNSR): A form of operating reserve provided by off-line generation that can be electrically synchronized to the system and increase output within 10 minutes in response to a contingency; also called 10-minute non-synchronized reserve. On-line generation that can increase output within 10 minutes also may provide this service because spinning reserve is higher quality than nonspinning reserve due to the fact that the possibility of a failed start does not exist.
10-minute spinning reserve (TMSR): A form of operating reserve provided by on-line generation thatcan increase output within 10 minutes in response to a contingency.
30-minute operating reserve (TMOR): A form of operating reserve provided by on-line or off-line operating reserve generation that can either increase output within 30 minutes or be electrically synchronized to the system and increase output within 30 minutes in response to a contingency. (Also see spinning and nonspinning.)
Adjusted Net Interchange (ANI): The difference between a market participant’s resources and liabilities at a location, measured in megawatt-hours. Resources include generation entitlements, cleared increment offers, external purchases of electric energy, and internal bilateral purchases for electric energy. Liabilities include load obligation, cleared decrement bids, external sales of electric energy, and internal bilateral sales for electric energy.
ancillary services: Services that ensure the reliability of and support for the transmission of electricity to serve load, including regulation and frequency response (regulation or automatic generator control), spinning reserve, nonspinning reserve, replacement reserve, and reactive supply and voltage control.
area control error (ACE): The instantaneous difference between the net actual and scheduled interchange (i.e., transfer of electric energy between two control areas), accounting for the effects of frequency bias and correction for meter error.
asset-related demand - A dispatchable or nondispatchable physical load that has been modeled within the ISO’s dispatch and settlement systems.
automatic generation control (AGC): The automatic adjustment of a control area’s generation to maintain its interchange schedule plus frequency bias.
assigned meter reader: The entity that submits to ISO the hourly and monthly megawatt-hours associated with the operation of an asset, which are used for settlement purposes.
auction revenue rights (ARR): Entitlements to receive revenues generated by the sale of Financial Transmission Rights in a specific auction.
automatic response rate (ARR): For generating resources that are providing regulation service, the amount of the resource’s output, in megawatt-minutes, that a market participant is willing to change between the resource’s regulation high limit and regulation low limit.
Balancing authority (BA): For an area comprising a collection of generation, transmission, and loads within metered boundaries (defined by NERC to be a balancing authority area), the entity responsible for integrating resource plans for that area ahead of time, maintaining the area’s load-resource balance, and supporting the area’s interconnection frequency in real time. The ISO is registered with NERC as a BA and is responsible for complying with NERC standards applicable to BAs.
Balancing authority area: For compliance with NERC reliability standards, an area comprising a collection of generation, transmission, and loads within metered boundaries for which a responsible entity (defined by NERC to be a balancing authority) integrates resource plans for that area ahead of time, maintains the area’s load-resource balance, and supports the area’s interconnection frequency in real time. This term is used interchangeably with control area.
baseload generating unit: A generating unit used to satisfy all or part of the minimum load of the system and, as a consequence, produce electric energy continuously and at a constant rate. These units are usually economic to operate on a day-to-day basis.
bid: A request to purchase megawatts at a specific location submitted into the market user interface.
bilateral contract: A contract between buyers and sellers of wholesale electricity that provides price and other terms and conditions. A bilateral contract may or may not be settled by ISO. Types of bilateral contracts for energy that are settled by ISO are Internal Bilateral for Load, Internal Bilateral for Market and External Transactions. There are also bilateral contracts for capacity.
black-start unit: A generating unit that has the ability to start without an outside electricity supply, generally by batteries or compressed air.
bottled generation: the situation when electricity produced in one area cannot be transmitted to other areas because of a transmission constraint.
bulk electric power grid, bulk electric power system, bulk electric system, bulk power grid, bulk power system :
bus: A point of interconnection to the system where power produced becomes available for transmission. Also, an electrical conductor that serves as a common connection for two or more electrical circuits.
busbar: Large rigid conductors typically used in substations to feed and direct power to two or more circuits.
capacity: The rated and continuous load-carrying ability, expressed in megawatts or megavolt-amperes, of generation, transmission, or other electrical equipment.
capacity commitment period: The one-year period from June 1 through May 31 of the following year for which Forward Capacity Market obligations are assumed and payments are made; same as a power year.
capacity factor: The ratio of the electrical energy a generating unit produced for a certain period of time to the electrical energy it could have produced at full operation during the same period.
capacity market: A market where generators receive compensation for investing in generating capacity. Load-serving entities, the market participants that secure electric energy, transmission service, and related services to serve the demand of their customers, make capacity payments to generators to ensure the long-term availability of sufficient generation capacity for the reliable operation of the bulk power grid.
capacity zone: To be determined before each Forward Capacity Auction, each export-constrained zone and any import constrained zone for which the amount of capacity projected to be installed in a load zone that is less than that load zone’s forecasted local sourcing requirement. In addition, adjacent load zones that are neither export-constrained or import-constrained are treated as a single capacity zone.
cascading outage: The uncontrolled successive loss of bulk electric system facilities triggered by an incident (or condition) at any location on the system, which results in the interruption of electric service that cannot be restrained from spreading beyond a predetermined area. (Also see interconnection-reliability operating limit.)
claim 10: The generation output level, expressed in megawatts, that a generator can reach from an off-line state within 10 minutes after receiving a dispatch instruction from ISO. This value is required as part of the generator’s offer data and is used by ISO New England to evaluate the generator’s contribution towards meeting operating- and replacement-reserve requirements.
claim 30: The generation output level, expressed in megawatts, that a generator can reach from an off-line state in 30 minutes after receiving a dispatch instruction from ISO. This value is required as part of the generator’s offer data and is used by ISO New England to evaluate the generator’s contribution towards meeting the New England Control Area’s operating and replacement reserve requirements.
claimed capability: A generator’s maximum output level as demonstrated to ISO.
cleared: In a market, when the quantity supplied (offered) has been matched to the quantity demanded (bid), the amount to be bought and sold has been determined, and settlement between buyers and sellers is possible.
coincident peak load: The highest value of the sum of all loads at one specific time in a particular geographic area. It is sometimes measured instantaneously and other times as the highest integrated hourly value.
combined cycle (CC): A technology that produces electricity from otherwise lost waste heat from a combustion turbine, which increases the unit’s efficiency for generating electricity.
commitment period: see capacity commitment period. Also, for the Day-Ahead and Real-Time Energy Markets, a period of continuous operation used to determine eligibility for NCPC credit.
congestion: A condition that arises on the transmission system when one or more restrictions prevents the economic dispatch of electric energy from serving load.
congestion component: The part of the nodal price that reflects the marginal cost of congestion at a given node or external node relative to the reference node.
constraint: Any transmission facility (or facilities) that operate at or over its limit (e.g., thermal limit, stability limit, or voltage limit).
contingency: The unplanned disconnection of a power system element, such as a transmission facility or a generator, from the electricity grid.
control area: See balancing authority area.
Control Performance Standard: A reliability standard that sets the limits of a Balancing Authority’s area control error over a specified time period.
cost of new entry (CONE): as a concept, the price of capacity in $/kw-month that is needed to attract sufficient new capacity. It is determined using clearing prices in Forward Capacity Auctions as described in the Market Rule.
customer of ISO New England: An entity that "does business" with ISO New England, such as a Transmission Customer or Market Participant.
Day-Ahead Energy Market: a market that produces financially binding schedules for the production and consumption of electricity one day before the operating day (see energy market and Real-Time Energy Market).
day-ahead load obligation (DALO): For each hour, the requirement that each market participant has for providing electric energy (megawatt-hours) at each node, external node, load zone, or the Hub equal to the megawatt-hours of its demand bids, decrement bids, and external transaction sales accepted in the day-ahead energy market at that location.
deactivation: The "mothballing" of a facility, such that with reconditioning it could be brought back into service in a relatively short time.
dead bus: An inactive bus; a point on the transmission system where electric energy is not available for transmission.
dead-bus logic: A procedure for assigning a price for electric energy from the nearest active bus to the dead (inactive) bus.
decrement bid: A financial bid to buy electricity at a specified location in the day-ahead energy market; virtual demand not associated with a physical load. In speaking, sometimes referred to as a "dec" (pronounced "deck").
demand: Load; the amount of electrical power used; the level of electricity consumption at a particular time measured in megawatts.
demand bid: A request to purchase an amount of electric energy at a specific location.
Demand resource, demand-side resource: A source of capacity whereby a customer reduces the demand for electricity from the bulk power system, such as by using energy-efficient equipment, shutting off equipment, and using electricity generated on site.
derate: A reduction in claimed capability, usually temporary and due to physical problems.
dispatch: When a control room operator issues electronic or verbal instructions to generators, transmission facilities, and other market participants to start up, shut down, raise or lower generation, change interchange schedules, or change the status of a dispatchable load in accordance with applicable contracts or demand bid parameters.
dispatchable asset-related demand (DARD): Demand that can be modified on the basis of the physical load’s ability to respond to remote dispatch instructions from the ISO.
distributed generation (DG): Generation provided by relatively small installations directly connected to distribution facilities or retail customer facilities. A small (24 kilowatt) solar photovoltaic system installed by a retail customer is an example of distributed generation.
distribution: The delivery of electricity to end users via low-voltage electric power lines (typically <69 kV) (see transmission); the transfer of electricity from high-voltage lines to lower-voltage lines.
disturbance: An unplanned event that produces an abnormal system condition; any perturbation to the electric system. Also, the unexpected change in the area control error caused by the sudden failure of generation or an interruption of load.
Disturbance Control Standard (DCS): The reliability standard that sets the time limit following a disturbance within which a Balancing Authority must return its area control error to within a specified range.
dual-fuel capability: When a generator has the flexibility and storage capacity to use oil as well as natural gas.
Eastern Interconnection: One of two major AC power grids in North America that spans from central Canada eastward to the Atlantic coast (excluding Quebec), south to Florida, and west to the foot of the Rocky Mountains (excluding most of Texas). The electric utilities within the Eastern Interconnection are electrically tied together during normal system conditions and operate at a synchronized frequency of 60 Hz average. The Eastern Interconnection is tied to the Western Interconnection, the Texas Interconnection, and the Quebec Interconnection, and other systems in Canada through numerous high-voltage DC transmission lines.
economic dispatch: The selection of generating resources to cover load as inexpensively as possible.
Economic Maximum (EcoMax): The highest unrestricted level of electric energy (MW) a resource is able to generate, representing the highest megawatt output available from the resource for economic dispatch.
economic-merit order: When the generators with the lowest-price offers are committed and dispatched first, and increasingly higher-priced generators are brought on line as demand increases.
Economic Minimum (EcoMin): The minimum amount of electric energy (MW) that a generating resource must be allowed to produce while under economic dispatch. A generator may request to self-schedule and increase its offered Economic Minimum to the desired level of MW.
electric energy, electrical energy: The ability of an electric current to produce work (heat, light, another form of energy); the generation or use of electric power over a specified time, usually expressed in gigawatt-hours (GWh), megawatt-hours (MWh), or kilowatt-hours (kWh).
electric energy market, energy market: A system for purchasing and selling electric energy using supply and demand to set the price (see electricity market and wholesale electric energy market). The energy markets operated by ISO are the Day-Ahead Energy Market and the Real-Time Energy Market.
electricity market: A system for purchasing and selling electricity using supply and demand to set the price (see electric energy market and wholesale electric energy market). In general, electricity markets include electric energy markets, capacity markets, and ancillary services markets, a part of which are regulation markets and operating reserve markets.
electric power: The rate at which electric energy is transferred or used to do work, measured in kilowatts (or watts or megawatts).
eMarket: A Web-based software application for use by market participants for submitting supply offers, demand bids, increment offers, decrement bids, and regulation offers into the Day-Ahead Energy Market and the Real-Time Energy Market.
Emergency: Abnormal condition of an electric system requiring manual or automatic action to maintain system frequency or to prevent the involuntary loss of load, equipment damage, or tripping of system elements that could adversely affect the reliability of the system or the safety of people or property. Could also be a fuel shortage requiring departure from normal operating procedures to minimize the use of such scarce fuel or any condition that requires the implementation of emergency procedures by ISO.
emergency maximum limit (or Emergency Max): The maximum generation amount (MW) that a generating resource can deliver for a limited amount of time without exceeding the specified limits of equipment stability and operating permits.
emergency minimum limit (or Emergency Min): The minimum generation amount (MW) that a generating resource can deliver for a limited amount of time without exceeding the specified limits of equipment stability and operating permits.
emergency outage: A type of unplanned outage when a piece of transmission equipment has a failure and comes out of service on its own or requires immediate operator intervention to remove it from service.
energy efficiency: A type of other demand resource that is an installed measure or a system on an end-use customer’s facility that reduces the total amount of electrical energy and capacity that otherwise would have been needed to deliver an equivalent or improved level of end-use service. Such measures or systems include the use of more efficient lighting, motors, refrigeration, HVAC equipment and control systems, and industrial process equipment.
equivalent demand forced-outage rate (EFORd): The portion of time a unit is in demand but is unavailable due to forced outages. See forced outage.
external node: A proxy location on the transmission system that is used for establishing prices for electricity that is being sold to or bought from outside of New England.
external transaction: A transfer of electric energy that crosses control area (balancing authority area) borders.
failure-to-activate flag: A flag placed on a forward-reserve resource when the resource fails to respond according to its offer data and the ISO’s instructions when asked to activate its claimed 10-minute nonspinning reserve or 30-minute operating reserve. A Failure-to-Activate flag results in a financial penalty.
failure-to-reserve flag: A flag placed on a market participant’s delivered forward-reserve megawatts associated with a reserve zone when these megawatts are less than the participant’s associated forward-reserve obligation. A Failure-to-Reserve flag results in a forfeiture of payment for any forward-reserve megawatts not delivered plus a financial penalty.
fast-start resource: A generation unit that can start up and be at full load in less than 30 minutes, which helps with recovery from contingencies and assists in serving peak demand.
Financial Transmission Rights (FTRs): A financial instrument that a market participant can buy to hedge the price risk of day-ahead congestion caused by constraints on the transmission system. FTR holders have a right to receive, or an obligation to pay, the dollar amounts associated with congestion based on the amount of electric energy (MW) flowing between two specific locations.
firm supply: Fuels under delivery contracts that include priority transportation service that cannot be interrupted or restricted.
first contingency: The largest impact on the system when a first power element (generation or transmission facility) of a system is lost. See N-1.
fixed demand: When market participants buy a specified amount of electricity as a price-taker. A clearing price above which demand is reduced is not specified.
flag: To designate or mark, as in to flag nonperformance with a market obligation or to flag a unit which has been committed to meet the requirements for voltage support or local second-contingency protection reliability.
forced outage: A type of unplanned outage that involves the unexpected removal from service of a generating unit, transmission facility, or other facility or portion of a facility due to an emergency failure or the discovery of a problem.
Forward Capacity Auction (FCA): The "descending-clock" annual auction of the Forward Capacity Market during which the price for capacity will be decreased until the quantity of capacity remaining in the auction equals the quantity of capacity needed.
Forward Capacity Market (FCM): In New England, the locational capacity market whereby the ISO will project the needs of the power system three years in advance and then hold an annual auction to purchase power resources to satisfy the region’s future needs. The aim of the FCM is to send appropriate price signals to attract new investment and maintain existing resources where and when they are needed, thus ensuring the reliability of the New England electricity grid.
forward reserve: The 10-minute nonspinning reserves and 30-minute operating reserves the ISO purchases on a forward basis on behalf of market participants.
Forward Reserve Market (FRM): In New England, a market used for acquiring the generating resources needed to satisfy the requirements for 10-minute nonspinning reserves and 30-minute operating reserves.
frequency: The rate of oscillation (cycles/second) of the alternating current in an electrical power system, measured in hertz (Hz). In the United States, the rate is 60 Hz.
frequency bias: A control area’s response to an interconnection frequency error, typically expressed in megawatts per 0.1 Hz (MW/0.1 Hz).
generating resource, generating unit, generator: A facility that produces electric energy (see resource).
generation: The production of electric energy from other sources of energy, expressed in megawatts; supply.
grid: The network of the transmission lines, substations, and associated equipment of an electric power system.
heat rate: A measure of the efficiency of a thermal power plant; the amount of heat, measured in British thermal units (Btus), required to produce a kilowatt-hour of electrical output. The lower the heat rate, the more efficient the facility.
hour ending (HE): A term that denotes the preceding hourly time period. For example, 12:01 a.m. to 1:00 a.m. is hour ending 01. Hour ending 18 is the time period from 5:01 p.m. to 6:00 p.m.
hub: A specific set of predefined nodes for which locational marginal prices are calculated and used to establish a reference price for electric energy purchases and the transfer of day-ahead adjusted load obligations and real-time adjusted load obligations and for the designation of Financial Transmission Rights. The current New England hub consists of 32 nodes.
Hydro-Quebec Interconnection Capability Credit (HQICC): A monthly value that reflects the annual installed capacity benefits of the HQ Interconnection, as determined by the ISO using a standard methodology on file with FERC.
increment offer: A financial offer to sell electric energy at a specified location in the day-ahead energy market; virtual supply not associated with a physical generator. In speaking, sometimes referred to as an "inc" (pronounced "ink".)
Independent System Operator (ISO): An independent, federally regulated organization formed at the recommendation of FERC to impartially coordinate, control, and monitor the operation of a regional bulk electric power system, including the dispatch of electric energy over the system and the monitoring of the electricity markets, for ensuring the safety and reliability of the system.
inframarginal revenues: The revenues earned by generators through the electric energy market that are in excess of the generators’ short-run variable costs for fuel and other operating expenses, which assists in recovering fixed costs, the largest portion being capital costs.
injection - A location on the transmission system where generation is injected, also source.
in merit, in merit order: The designation for a supply offer that is accepted and dispatched because it was less expensive than other accepted and dispatched supply offers. Also see economic-merit order.
interchange: Transfers of electric energy that cross Balancing Authority boundaries.
Interchange Authority: An entity responsible for authorizing the implementation of valid and balanced interchange schedules between Balancing Authority Areas and ensuring the communication of interchange information needed for reliability assessment.
interchange schedule: The agreed-upon specifications for the transfer of electric energy between two control areas including, for example, the size of the transaction in megawatts, the start and end times, the beginning and ending ramp times, and the rate.
interconnection: The connection between two bulk electric power systems or control areas.
interconnection-reliability operating limit (IROL): A system operating limit that, if violated, could lead to instability, uncontrolled separation, or cascading outages that have an adverse impact on the reliability of the bulk electric power system.
intermediate-load generating unit: A generating unit that is used during the transition between baseload and peak-load requirements.
intermittent power resource (IPR): A resource whose output amount and availability are intermittent and not subject to the control of ISO New England or the plant operator because of the intermittent source of fuel (e.g., wind, solar, run-of-river hydro) the resource uses or contractual obligations (e.g. qualifying facilities). IPRs can be resources having less than 5 MW operating within the distribution system.
Internal Bilateral for Load (IBL): An IBT in the Real-Time Energy Market is when the buyer receives a reduction in load obligation and the seller receives a corresponding increase in load obligation in the amount of the megawatt sale.
Internal Bilateral for Market (IBM) -
An IBT for Energy under which the buyer receives a reduction in its day ahead adjusted load obligation and a real time adjusted load obligation while the seller receives a corresponding increase in its day ahead adjusted load obligation and in its real time adjusted load obligation in the amount of the megawatt sale. (An IBT for Energy can apply in the Day-Ahead Energy Market and Real-Time Energy Market or just the Real-Time Energy Market.)
An IBT for Regulation under which the buyer receives a reduction in the regulation obligation and the seller receives a corresponding increase in the regulation obligation in the amount of the megawatt sale.
internal bilateral transaction (IBT): The purchase or sale of electric energy or regulation obligations between two market participants internal to New England.
interruptible load: Load that can be interrupted by the system operator.
intertie: The circuit that connects two or more control areas or systems.
line loss: The power lost (turned to heat) during the transmission or distribution of electricity.
LMP Calculator: The software tool used to calculate locational marginal prices.
load: Demand; the amount of electrical power used; the level of electricity consumption at a particular time measured in megawatts.
load factor: The ratio of the average hourly use of electric energy (average load in kilowatts) to the maximum hourly use of electric energy (peak load), expressed as a percentage.
load management: The use of installed measures, systems, or strategies by end-use customers to curtail their electrical usage during peak hours or shift electrical use to off-peak hours to reduce the amount of capacity needed to deliver an acceptable level of service to those facilities.
load response: A reduction of load by demand-side resources
load obligation: The sum of metered load, exports, and load-shifting contracts for which a lead participant is financially responsible.
load pockets: Areas of the system where the transmission capability is not adequate to import capacity from other parts of the system and demand is met by relying on local generation.
load-serving entity (LSE): An entity that secures electric energy, transmission service, and related services to serve the demand of its customers.
load shedding: Controlled or scheduled power outages (controlled blackouts) to balance the demand for electricity with limited supply.
load zone: An aggregation of nodes within a specific area. There are currently 8 load zones in New England, and they have the same boundaries as the New England reliability regions.
local sourcing requirement: The portion of the total capacity requirement of the load in an FCM capacity zone that must be purchased from resources within that zone after accounting for the capacity that can reliably be imported into that zone.
location: A node, external node, load zone, or hub.
Locational Forward Reserve Market: see Forward Reserve Market.
locational marginal price (LMP): The calculated price of electric energy at a node, load zone, reliability region, and the hub.
loss-of-load evaluation (LOLE): An analysis that determines the amount of installed capacity the system needs to meet the NPCC and ISO resource adequacy planning criterion to not disconnect firm load more frequently than one day in 10 years.
marginal loss component: The component of the nodal price that reflects the marginal loss at a node.
marginal resource: The price-setting generator; the last unit committed to meet load in economic dispatch.
market participant: An entity that conducts business in one or more electricity market. Specifically, an entity in New England that has executed a Market Participant Service Agreement or on whose behalf an unexecuted Market Participant Service Agreement has been filed with the Federal Energy Regulatory Commission (FERC).
merit order: The order that ISO New England designates generators to operate based on the lowest to highest cleared offers, until the demand for electric energy is met.
mileage payment: A payment to a generator providing regulation service according to how much the generators output fluctuates (in megawatts) in response to a regulation signal sent by the ISO.
minimum generation emergency: An emergency declared by the ISO in which the ISO anticipates requesting one or more generating resources to operate at or below its economic minimum limit so that it can manage, alleviate, or end the emergency.
N-1-1, N-2: A second contingency; the loss of the facility that would have the largest impact on the system after the first facility is lost.
nameplate capacity, nameplate: The rating of a generator and a measure of its ability to produce electricity.
Net Commitment-Period Compensation (NCPC): The payment to an eligible resource that did not fully recover its costs from the either the Day-Ahead or Real-Time Energy Market. The accounting for the provision of these credits is performed daily for each market and considers a resource’s total offer amount for generation, including start-up fees and no-load fees, compared with its total energy-market value during the day. If the total value is less than the offer amount, the difference is credited to the market participant.
net energy for load: The net generation output within a control area, accounting for energy imports from other areas and subtracting energy exports to others. It includes system losses but excludes the energy required to operate pumped storage plants.
network model: The computer-based representation of physical transmission system assets used by ISO New England.
New England Power Pool (NEPOOL): A group formed in 1971 by the region’s private and municipal utilities to foster cooperation and coordination among the utilities in the six-state region for ensuring a dependable supply of electricity. Today, NEPOOL members are ISO stakeholders and market participants.
nodal price - The price for electric energy received or furnished at a node for any given hour.
node (or nodal): A point on the transmission system for which nodal prices are calculated.
no-load cost or fee: The amount, in dollars per hour, that must be paid to a generating unit scheduled to operate in the New England market. A payment in addition to the start-up fee and price offered to supply electric energy for each hour.
noncoincident peak load: The sum of contributor peak loads (MW) that occurred on different days and hours.
nonfirm gas: Gas delivered under a contract that includes transportation service subject to interruption to avoid interfering with or restricting gas deliveries having a higher priority.
no-notice service: When gas pipeline companies provide gas on short notice.
nonspinning: Off-line generation not synchronized to the system.
nonspinning reserve, nonsynchronized reserve: Off-line generation that can quickly be electrically synchronized to the system and increase output to respond to a contingency and serve demand.
NX-12 and/or NX-12E: Forms submitted to ISO New England that identify technical data associated with assets.
off-peak hours: In New England, weekday hours between 11:00 p.m. and 7:00 a.m. and all day Saturdays, Sundays, and holidays. See peak hours.
one day in 10 years or "1 in 10": The Northeast Power Coordinating Council (NPCC) resource reliability criterion that states that the probability of disconnecting firm load as a result of a resource deficiency can be no greater than one day in 10 years.
on-peak hours: From 7:00 a.m. through 11:00 p.m. on all nonholiday weekdays; same as peak hours.
operable capacity analysis: An estimate of the availability of a system’s net capacity under specific scenarios and load conditions. The results are in the form of operable capacity margins, which show either an expected system surplus or a deficiency in meeting the conditions.
operable capacity margin: The amount of resources that must be operational to meet peak demand plus operating-reserve requirements.
operating day: The calendar day, beginning at midnight and ending at 2400 hours, for which transactions in the New England markets are scheduled.
operating reserve: The megawatt capability of a power system greater than system demand, which is required for providing frequency regulation, correcting load forecasting errors, and handling forced outages, drawn from spinning and nonspinning sources of power. Also, the synchronized or nonsynchronized reserves that may be used to recover from a contingency.
out of economic-merit order (out of merit): Capacity (in megawatts) that is more expensive than the marginal, price-setting, supply offer.
out-of-market compensation: Payments to resources outside the electricity market clearing processes, such as Reliability Agreements.
out-of-merit cost: A payment to a generator for operating when it is more expensive for it to do so than the price-setting generator.
ownership share: For settlement purposes, a right or obligation for a percentage share of all credits or charges associated with a generating resource at a node where the resource is interconnected to the New England transmission system.
participant: See market participant.
peak hours: In New England, the hours between 7:00 a.m. and 11:00 pm on nonholiday weekdays; same as on-peak hours.
peak-load generating unit: A generating unit that is used to meet system requirements during peak-load periods when the demand on the system is the greatest. These units typically operate at a relatively high cost and run when the price of electric energy is high.
planned outage: The planned inoperability of a generator, generally to perform maintenance.
Planning Authority (PA): An entity responsible for coordinating and integrating transmission facility and service plans, resource plans, and protection systems. The ISO has registered with NERC as a PA and is responsible for complying with NERC standards applicable to a PA.
posturing: Instances in which generators are directed to operate below their economic dispatch point for reliability reasons.
power: See electric power.
power system: The elements of an electrical system, including generation units, transmission lines, distribution lines, substations, and other equipment. See bulk power system.
power year: A year that runs from June 1 through May 31 of the following year used to calculate the Installed Capacity Requirement (ICR) for the New England Control Area. The ISO calculates the ICR for each upcoming power year through the capacity commitment period associated with a Forward Capacity Auction. Each power year is the same as a capacity commitment period.
price quantity pairs: Price-sensitive bid-block information that consists of a quantity of megawatts and the available dollar price for the megawatts.
price response: The reduction of electricity consumption in response to a price signal.
price-sensitive demand: The purchase of electric energy up to a certain price.
price separation: in a locational market, when different clearing prices exist at different locations. In an energy market, price separation is due to transmission constraints and congestion. In the Forward Capacity Auction, when capacity zones experience a difference in price as a result of the quantity of capacity remaining in each capacity zone as the descending clock drops in price.
price-taker: A market participant whose buying and selling actions do not affect the market price; a generator that has offered into the market at zero or has self-scheduled, is willing to operate at any price, and is not eligible to set clearing prices.
pricing node (Pnode): A location (external interface, load node, individual unit node, load zone, and the Hub, which are collections of pnodes) where ISO New England calculates and publishes prices for electric energy.
prime mover: The motive force that drives an electric generator, such as a water or steam turbine, which converts thermal or hydraulic energy into mechanical energy that will in turn be converted to electrical energy. Falling water, heat, wind, nuclear, fossil fuels (oil, natural gas, coal), biomass, and the sun are fuels used to drive prime movers.
pumped storage: a generating facility where water is pumped up to a storage pond, during periods of low demand and lower cost, to produce electricity during periods of high demand and higher prices.
quick-start resource: See fast-start resource.
Real-Time Energy Market: a market that balances differences between the day-ahead scheduled amounts of electricity needed and the actual real-time load requirements (see Day-Ahead Energy Market and energy market).
real-time load obligation (RTLO): For each hour, the requirement that each market participant has for providing electric energy (megawatt-hours) at each node, external node, load zone, or the Hub equal to the megawatt-hours of load, including external transaction sales and internal bilateral transactions that transfer these obligations.
real-time prices: Locational marginal prices resulting from the dispatch of power within the operating day.
real-time reserve market: An ISO market where resources capable of providing 10-minute and 30-minute reserves are designated in real time, for which they are paid the reserve market clearing price.
redeclaration: Restatement of a resource’s availability, limits, or other offer or bid parameters, except price-related supply offer data, which market participants submit to ISO New England and that reflect changes in the status or capability of the participant’s resource. Also, changes that ISO New England makes to a resource on the basis of the resource’s actual performance.
reconfiguration auction: An auction of the Forward Capacity Market whereby capacity supply obligations using a static double auction are traded monthly, seasonally, and annually to clear supply offers and demand bids for each capacity zone.
Regional Transmission Organization (RTO): An independent regional transmission operator and service provider established by FERC and that meets FERC’s RTO criteria, including those related to independence and market size. The RTO controls and manages the high-voltage flow of electricity over an area generally larger than the typical power company’s service territory for its distribution system.
regulation: The capability of specially equipped generating resources to increase or decrease their generation output every four seconds in response to signals they receive from the ISO to control slight changes on the system. This capability is necessary to balance supply levels with the second-to-second variations in demand.
regulation market: A market in which load-serving entities pay for regulation service on the basis of real-time load obligations and market participants satisfy regulation requirements by providing the service from their own resources, through internal bilateral transactions for regulation, or by purchasing regulation from the market.
reliability: The assurance that power is available even under adverse conditions, such as unplanned outages of generation or transmission lines.
reliability adequacy: A measure of the reliability of the bulk power system to meet demand and the sufficiency of the system’s generating resources.
Reliability Agreement: An agreement made between the ISO and a generation owner whereby an approved generator continues to operate, even when it is not economical to do so, to ensure system reliability, and whereby the generation owner recovers the fixed costs for operation; formerly termed Reliability Must-Run (RMR) Agreement.
reliability coordinator (RC): The entity with the highest level of authority for reliably operating the bulk electric system, including the authority to prevent or mitigate emergency operating situations in next-day and real-time operations. The ISO has registered with NERC as an RC and is responsible for complying with NERC standards applicable to an RC.
Reliability Coordinator Area: The collection of generation, transmission, and loads within the boundaries of the reliability coordinator. The boundaries of a Reliability Coordinator Area coincide with one or more Balancing Authority Areas.
Reliability Regions: A defined region of the New England Control Area that reflects the operating characteristics of, and the major transmission constraints on, the New England transmission system. These regions contain the load zones.
re-offer period: Normally, the period between 16:00 and 18:00 the day before the operating day when market participants submit revised supply offers and revisions to demand bids for any dispatchable asset-related demand resources. The hours may change depending on software impacts or other events.
Reserve Adequacy Assessment or Analysis: The analyses ISO New England performs at the close of the re-offer period to ensure that adequate resources are committed to meet the forecasted load and operating reserve requirements for the Real-Time Energy Market.
reserve capacity: The amount of capacity a system can supply greater than what is required to meet demand.
Reserve Sharing Group (RSG): A group whose members consist of two or more Balancing Authorities that collectively maintain, allocate, and supply operating reserves required for each Balancing Authority’s use in recovering from contingencies within the group. Adjacent Balancing Authorities become a Reserve Sharing Group, if the transfer of electric energy from an adjacent Balancing Authority to aid in recovery is scheduled to be ramped in within 10 minutes or less. The ISO has registered with NERC as an RSG and is responsible for complying with NERC Standards applicable to an RSG.
Reserve-Shortage Pricing Event: When the control area is experiencing a deficiency in total 10-minute operating reserves or the ISO is taking actions to maintain 10-minute operating reserves. The ISO will also declare this condition when the control area is experiencing a deficiency in total operating reserves that has lasted for at least four hours and the ISO has begun taking actions to maintain or restore operating reserves.
resource: Any source of electric energy that increases the availability of capacity (in megawatts), such as a dispatchable load, a demand-response resource, or an electricity import or external transaction. Also see generating resource.
resource adequacy: The ability of a bulk electric power system to supply the aggregate electrical demand and energy requirements (i.e., the electrical loads of all the customers at all times plus external transaction sales to other control areas), taking into account scheduled and reasonably expected unscheduled outages of system devices (e.g., generators, transformers, circuits, circuit breakers, or bus sections). Annual expected system resource adequacy is calculated in terms of system loss-of-load expectation, accounting for load forecast uncertainty caused by weather and resource availability and reflecting assumed forced and scheduled outages.
resource planner (RP): An entity that develops a long-term plan (generally one year and beyond) for the resource adequacy of specific loads within a Planning Authority area (i.e., the customer demand and energy requirements, including the electrical loads of all customers at all times plus external transaction sales to other control areas). The ISO has registered with NERC as an RP and is responsible for complying with NERC standards applicable to an RP.
retirement: The permanent removal from service of a facility, which cannot return to service without major refurbishment.
seams: The interface between two control areas, systems, and markets (see seams issues).
seams issues: Trading barriers between adjoining wholesale electricity markets resulting from the use of different rules and procedures by the neighboring markets, which can obstruct the trading or sharing of electric capacity and energy between the two markets and affect the reliability of each system.
second contingency: The loss of the facility that would have the largest impact on the system after the first facility is lost. A system constraint met by maintaining an operating reserve that can increase output when the first contingency occurs. See N-1-1, N-2.
self-schedule: Is the action of a market participant to commit or schedule its resource at a determined output level to provide generation within an hour, regardless of price or whether the ISO could have scheduled or dispatched the resource to provide the service.
self-supply: When a participant provides itself with a market product from its own resources rather than purchasing it from the market.
settlements model: Computer-based software used to determine financial settlements in ISO New England.
Settlement Market System (SMS): A Web-based system that allows market participants to submit internal bilateral transactions (IBTs) and meter readings.
settlement-only generator (SOG), settlement-only unit: A unit that generates less than 5 MW and is entitled to receive capacity credit but is not centrally dispatched by the ISO control room and is not monitored in real time.
shortage event: A designated period (hours) of system stress during which capacity resources are most needed on the basis of system conditions.
sink, sink point: The point on the transmission system where electric energy is withdrawn. A Financial Transmission Right delivery point.
source, source point: The point on the transmission system where electric energy is injected. A Financial Transmission Right location of origin.
special protection system: Equipment installed on a power system used to perform functions other than isolating electrical faults.
spinning: On-line capacity electrically synchronized to the system.
spinning reserve: The reserve capability that a generator can fully convert into electric energy within 10 minutes after receiving a request from ISO New England to do so.
spot market: A market that typically involves short-term, often interruptible contracting and immediate delivery of specified volumes of electric energy, as opposed to bilateral trading. In New England, the Real-Time Energy Market is a spot market.
Standard Market Design: New England’s wholesale electricity market structure that incorporates locational marginal pricing, day-ahead and real-time energy markets, and risk-management tools to hedge against the adverse impacts of having to pay higher locational marginal prices when transmission congestion occurs.
Start-Up Fee: The dollar amount that must be paid to an owner each time the generating resource is scheduled to start-up.
step-down transformer: A transformer, usually located on the distribution system, that converts electricity from a higher to a lower voltage.
step-up transformers: A transformer, usually located at a generator site, that converts electricity from a lower to a higher voltage.
strike price: The price at which an option contract entitles a buyer to purchase energy.
Supervisory Control and Data Acquisition (SCADA): A type of equipment that can remotely control, communicate with, and monitor the generation, transmission, and distribution of electric energy.
supply: Electricity delivered to the system; generation.
supply margin: Available generation (megawatts) beyond the amount needed to meet demand.
supply offer: A resource’s proposal to furnish electric energy at a node or provide regulation, which includes a dollar price and megawatt quantity along with other information.
supply stack: Generator offers ordered by ascending price.
synchronous condenser: Either a combustion turbine or hydro resource that is synchronized to the New England transmission system and operates as a motor (i.e., it is consuming energy). Also, rotating equipment (or a generator with 0 MW output) that can provide dynamic voltage support, typically designed and operated as separate equipment from generating units.
synchronous generator: A typical type of generator connected to the network.
system operating limit (SOL): A value (such as MW, MVar, ampere, frequency, or volt) for the most limiting of the prescribed operating criteria for a specified bulk electric power system configuration that ensures operation within acceptable reliability criteria. (Also see interconnection-reliability operating limit.)
tie line: A transmission line that connects two control areas; an interconnection.
transfer capability: The amount of megawatts that interconnected electricity systems under specified conditions can reliably transfer from one system to the other over all transmission lines that connect the systems.
transmission: The transporting of electricity through high-voltage lines to distribution lines (see distribution).
transmission congestion: see congestion.
transmission line: Any line with a voltage greater than or equal to 69 kV that carries bulk power over long distances. Typical industry voltages are 69 kV, 115 kV, 138 kV, 230 kV, and 345 kV.
Transmission Operating Agreement: An agreement between an RTO and a utility whereby the RTO will pay the utility for its transmission system costs in exchange for control of the transmission.
transmission operator (TOP): An entity responsible for the reliability of its "local" transmission system and that operates or directs the operations of the transmission facilities. The ISO has registered with NERC as a TOP and is responsible for complying with NERC standards applicable to a TOP.
transmission owner (TO): An entity that owns and maintains transmission facilities.
transmission planner (TP): An entity that develops a long-term plan (generally one year and beyond) for the reliability (adequacy) of the interconnected bulk electric transmission systems within its portion of the Planning Authority area. The ISO has registered with NERC as a TP and is responsible for complying with NERC standards applicable to a TP.
transmission service provider (TSP): An entity that administers the transmission tariff and provides transmission service to transmission customers under applicable transmission service agreements. The ISO has registered with NERC as a TSP and is responsible for complying with NERC standards applicable to a TSP.
unplanned outage: When equipment is forced out of operation due to a problem that was discovered, and the request for the outage did not meet the timing requirements for it to be considered a planned outage. Unplanned outages are categorized as emergency outages or forced outages.
uplift: Payments to resources operated out of merit. See Net Commitment-Period Compensation.
virtual demand: See decrement bid.
virtual supply: See increment offer.
voltage regulation: When an electrical system provides constant voltage over a range of
wholesale electric energy market: The buying, selling, and reselling of the electric energy generated by a bulk power system to meet the system’s demand for electric energy. New England’s wholesale electric energy markets are the Day-Ahead or Real-Time Energy Market. (Also see energy market.)
wholesale electricity: Power that is bought and sold among generators, utilities, municipalities, and other wholesale entities (see market participants).
wholesale electricity markets, wholesale electric power market: The buying, selling and reselling of electric energy, ancillary services and capacity at the transmission level.
withdrawal: The location where power is taken off (withdrawn) from the system, see sink, sink point.
zonal price: The hourly price for electric energy received in a defined load zone calculated using a load-weighted average of the locational marginal prices for the nodes within the load zone.
ACE: Area Control Error
AGC: Automatic Generator Control
ARA: Annual Reconfiguration Auction
ARD: Asset Related Demand
ARR: Auction Revenue Right
Appendix H: Appendix H of Market Rule 1, Operations during Cold Weather Conditions
ASM: Ancillary Services Market
BA: Balancing Authority
BACT: best available control technology
BCC: backup control center
C&LM: conservation and load management
CA: Control Area
CAA: U.S. Clean Air Act
CAGR: compound annual growth rate
CAIR: Clean Air Interstate Rule
CAMS: Customer and Asset Management System
CARL: Control Area Reliability
CC: Combined Cycle (generator)
CCP: Capacity Commitment Period
CEII: Critical Energy Infrastructure Information
CELT Report: Forecast Report of Capacity, Energy, Loads, and Transmission
CFR: Code of Federal Regulations
CIP: Critical Infrastructure Protection
CONE: Cost of New Entry
COP: Current Operating Plan
COS: cost of service
CP: Clearing Price
CPI: Consumer Price Index
CPS: Control Performance Standard
CPS: Critical Path Standard
CT: Combustion Turbine (generator) or Connecticut Load Zone
CTR: Capacity Transfer Rights
DA: Day-Ahead (prior to the operating day)
DAALO: Day-Ahead Adjusted Load Obligation
DAANI: Day-Ahead Adjusted Net Interchange
DAGO: Day-Ahead Generation Obligation
DALO: Day-Ahead Load Obligation
DALRP: Day-Ahead Load Response Program
DAM: Day-Ahead Energy Market
DARD: dispatchable asset-related demand
DC (see HVDC): direct current
DCF: Discounted Cash Flow
DCS: Disturbance Control Standard
DDP: Desired Dispatch Point
DEC’s: Decrement Bid
DG: distributed generation
DOE: Department of Energy
DRP: demand-response provider
DRR Pilot: Demand-Response Reserve Pilot Program
DSM: demand-side management
EBB: electronic bulletin board
EcoMax: Economic Maximum
EcoMin: Economic Minimum
ECP: energy clearing price
ED: Economic Dispatch
EES: Enhanced Energy Scheduler
EFOR: equivalent forced-outage rate
EFORd: Demand Estimated Forced Outage Rate
EHV: extra-high voltage
EIS: Environmental Impact Statement
EMF: electromagnetic field
eMkt: Software application used to submit Offers and Bids into the ISO Market
EMS: Energy Management System
EP: Enrolling Participant
EPAct: Energy Policy Act of 2005
ERO: Electric Reliability Organization
ET: External Transactions
FACTS: flexible alternating-current transmission system
FAM: Financial Assurance Management
FAQ: Frequently Asked Question
FAP: Financial Assurance Policy
FCA: Forward Capacity Auction
FCM: Forward Capacity Market
FCTS: Forward Capacity Tracking System
FERC: Federal Energy Regulatory Commission
FPA: Federal Power Act
FRM: Forward Reserve Market
FTR: Financial Transmission Right
FRM: Forward Reserve Market
GADS: Generating Availability Data System
GIS: gas-insulated substation, gas-insulated switchgear, Generation Information System, Geographic Information System
GRT: Generation Requirements for Transmission Constraints
HQICC: Hydro Quebec Interconnection Capability Credits
HVDC: high-voltage direct current
IA: interconnection agreement
IBCS: Internet Based Communication System
IBL: Internal Bilateral for Load
IBM: Internal Bilateral for Market
IBT: Internal Bilateral Transaction
ICAP: Installed Capacity
ICR: Installed Capacity Requirement
ICU: Internal Combustion Unit (generator)
IGCC: integrated coal-gasification combined cycle
IMO: Independent Electricity Market Operator (Ontario)
INC’s: Increment Bid
IPP: independent power producer
IROL: interconnection-reliability operating limit
IRH: Interconnection Rights Holders
ISO: Independent System Operator, ISO New England Inc.
LCC: local control center
LDC: local distribution company
LICAP: Locational Installed Capability
LMP: Locational Marginal Pricing
LNS: local network service
LOLE: loss-of-load expectation
LOS: loss of source
LPG: liquefied petroleum gas
LRP: load-response program
LSC: Local Second Contingency
LSCPR: Local Second Contingency Protection Resource
LSE: Load Serving Entity
LTTR: Long-term Transmission Right
MAIN: Mid-America Interconnected Network
MC: Markets Committee
ME: Maine Load Zone
MIS: Market Information Server
MOU: Memorandum of Understanding
MPSA: Market Participant Service Agreement
MR1: Market Rule 1 (Section III of the Transmission, Markets & Services Tariff)
MRR: Manual Response Rate
MSS: Market Support Services
MSW: municipal solid waste
MUI: market user interface
muni: municipal utility
MWh: Megawatt Hour
N-1: first-contingency loss
N-2: second-contingency loss
NAAQS: National Ambient Air Quality Standards
NB: New Brunswick
NCPC: Net Commitment Period Compensation
NECPUC: New England Conference of Public Utility Commissioners
NEL: net energy for load
NEMA/Boston: Northeastern Massachusetts/Boston load zone
NEPOOL: New England Power Pool
NERC: North American Electric Reliability Council
NESCOE: New England States Committee on Electricity
NH: New Hampshire Load Zone
NIETC: National Interest Electric Transmission Corridor
NOPR: Notice of Proposed Rulemaking
NPCC: Northeast Power Coordinating Council, Inc.
NRI: Northeast Reliability Interconnection
NYISO: New York Independent System Operator
O&M: operations and maintenance
OASIS: Open Access Same-Time Information System
OATT: Open Access Transmission Tariff
ODR: Other Demand Resource
OP: operating procedure
OP 4: ISO Operating Procedure No. 4, Action during a Capacity Deficiency
OP 8: ISO Operating Procedure No. 8, Operating Reserve and Regulation
OP 17: ISO Operating Procedure No. 17, Load Power Factor Correction
OP 19: ISO Operating Procedure No. 19, Transmission Operations
OP 21: ISO Operating Procedure No. 21, Actions during an Energy Emergency
OR: Operating Reserve
PA: Planning Authority
PAR: phase-angle regulator; phase-angle regulating transformer
PER: Peak Energy Rent
pnode: pricing node
POLR: provider of last resort
PPA: Power Purchase Agreement
PTDF: Power Transfer Distribution Factor
PTF: Pool Transmission Facility
PTO: Participating Transmission Owners
PTOAC: Participating Transmission Owners Administrative Committee
PUC: Public Utility Commission
PUCHA: Public Utility Holding Company Act
PURPA: Public Utility Regulatory Policies Act
PV: solar photovoltaic
QUA: Qualified Upgrade Awards
RAA: Reserve Adequacy Analysis, Resource Adequacy Assessment
RBA: Requested Billing Adjustment
RC: Reliability Committee, reliability coordinator
RCP: Regulation Clearing Price
RCPF: Reserve Constraint Penalty Factor
REC: Renewable Energy Certificate, Renewable Energy Credit
RFP: Request for Proposals
RGGI: Regional Greenhouse Gas Initiative
RI: Rhode Island Load Zone
RIG: Remote Intelligent Gateway
RMCP: Reserve Market Clearing Price
RMR: Reliability Must Run
RNA: Restated NEPOOL Agreement
RNS: Regional Network Service
ROE: Return On Equity
ROS: Rest of System
ROW: right of way
RP: resource planner
RPS: Renewable Portfolio Standard
RRA: Resource Reliability Assessment
RSC: Resource Scheduling and Commitment
RSG: Reserve Sharing Group
RSP: Regional System Plan
RTANI: Real-Time Adjusted Net Interchange
RTANID: Real-Time Adjusted Net Interchange Deviation
RTALO: Real-Time Adjusted Load Obligation
RTGO: Real-Time Generation Obligation
RTLO: Real-Time Load Obligation
RTM: Real-Time Energy Market
RTMP: real-time marginal price
RTO: Regional Transmission Organization
SAS70: Statement on Auditing Standards No. 70
SCADA: System Control and Data Acquisition
SCC: Seasonal Claimed Capability
SCR: Special Constrained Resources
SEMA: South East Massachusetts Load Zone
SIP: state implementation plan
SIS: System Impact Study
SMD: Standard Market Design
SME: subject matter expert
SMS: Settlement Market System
SOG: settlement-only generator
SOI: show of interest
SOL: system operating limit
SPD: scheduling, pricing, and dispatching
SPS: special protection system
STATCOM: static synchronous compensator
SVC: static VAR compensator
SVD: static VAR device
SWCT: Southwest Area of the Connecticut Load Zone
TADO: Total Amount Due and Owing
TCA: Transmission Cost Allocation
TMNSR: Ten-Minute Non-Spinning Reserve
TMOR: Thirty-Minute Operating Reserve
TMSR: Ten-Minute Spinning Reserve
TO: Transmission Owner
TOA: Transmission Operating Agreement
PAC: Planning Advisory Committee
TP: transmission planner
TRAGO: Transmission Related Abnormal Generation
TSA: Transmission Service Agreement or Transmission Security Analysis
TSO: Tariffs, Schedules, and OASIS
TTC: Total Transfer Capacity
UDG: Unit Desired Generation
UDS: Unit Dispatch System
UI: User Interface
VAR: Voltage Amperes Reactive
VOC: volatile organic compound
VT: Vermont Load Zone
WCMA: West Central Massachusetts Load Zone
WEM: Wholesale Electric Market
WSCC: winter seasonal claimed capability
VT: Vermont Load Zone
ME: Maine Load Zone
NH: New Hampshire Load Zone
WCMA: West Central Massachusetts Load Zone
SEMA: South East Massachusetts Load Zone
CT: Connecticut Load Zone
RI: Rhode Island Load Zone
NEMA: North East Massachusetts and Boston Load Zone