ACHL - Average Coincident Host Load - In calculating the amount of capacity a BTM:NG resource can sell in the wholesale market, the NYISO nets out the facility’s host load (the BTM:NG ACHL) to account for the capacity it provides to its own load. ACHL is a single megawatt value for each BTM:NG Resource for each Capability Year. Calculated as the average of the top twenty (20) Load hours of the BTM:NG Resource that occur within the top forty (40) Load hours for the NYCA, accounting for load growth and weather normalization. The ACHL value describes average BTM:NG Resource Load during NYCA peak load conditions.

AMP - Automated Mitigation Process - AMP is a selective bid mitigation mechanism that is automatically activated when conditions are not workably competitive.

AMS - Automated Market System - The NYISO ICAP AMS is a secure, web-enabled, electronic application that replaced the manual legacy market process. The AMS includes features that support all of the traditional auction participation requirements with respect to submitting bids, offers, and relevant auction data, and also supports the datamanagement, retrieval, and general information requirements for participating in the ICAP market. Finally, the AMS operates the auction and supports the NYISO internal administration functions required to administer the market.

ATBA - Annual Transmission Baseline Assessment - An assessment conducted by the NYISO staff in cooperation with Market Participants, to identify the System Upgrade Facilities that Transmission Owners are expected to need during the time period covered by the Assessment to comply with Applicable Reliability Requirements, and reliably meet the load growth and changes in load pattern projected for the New York Control Area.


BACT - Best Available Control Technology - The emissions control method that achieves the greatest emission reduction within a pre-determined criterion for cost per ton of emissions reduction.

Balance of Period - Remaining months of a capabiltiy period.

BES - Bulk Electric System - All Transmission Elements operated at 100 kV or higher and Real Power and Reactive Power resources connected at 100 kV or higher.

BIC - Business Issue Committee - The BIC is a standing committee of the NYISO which establishes rules related to business issues and provides a forum for discussion of those rules and issues.

BMS - Business Management System - The BMS is the suite of applications that comprise the SCUC, RTC and RTD software. This software is used to develop schedules and prices for the NYISO's Energy and Ancillary Services markets.

BPCG - Bid Production Cost Guarantee - A BPCG is available to ensure a resource is able to recover its operating costs when instructed to operate by the NYISO. A BPCG provides an incentive for resources to offer marginal costs and to allow the NYISO market software to make scheduling determinations. A supplier is eligible for a BPCG payment if it will not recover its offered costs for scheduled Ancillary Services, Minimum Generation, Start-Up Bid Costs and Incremental Energy through market revenues, including energy and ancillary services payments. The guarantee is separately available for DAM and RT schedules. The need for a payment is assessed over the entire Market Day. General Application: Suppliers that are economically scheduled by the NYISO markets and/or following NYISO dispatch instructions.

BSM - Buyer-Side Mitigation - Buyer-Side Mitigation measures are designed to prevent "uneconomic entry" of capacity that would artificially suppress capacity prices. All new capacity entering Zone J or Zone G-J is subjected to two different tests to determine if they are exempt under either. If the new capacity is not exempt, it is subject to a capacity offer floor. The offer floor for is set at the lower of the provider's own cost of the price calculated based on the ICAP Demand Curve (default offer floor). Establishing an offer floor for new market entrants helps to avoid situations where capacity providers might use out-of-market revenues to reduce their bids, establishing an artificial pricing signal that could ultimately force other capacity providers out of the market or obscure the possible need for additional capacity in order to preserve reliabilty.

BTM - Behind the Meter - A  renewable energy generating system that produces power intended for on-site use in a home, office building, or other commercial facility.

BTM:NG - Behind the Meter Net Generation - A facility within a defined electrical boundary comprised of a Generator and a Host Load located at a single point identifier , where the Generator routinely serves, and is assigned to, the Host Load and has excess generation capability after serving that Host Load. A BMT:NG resource is eligible to participate in the Energy, Ancillary Service, and Capacity Markets.

BTU - British Thermal Unit - A measurement of energy, BTU is commonly used to measure the energy content of various fuels and steam. One BTU is the amount of heat required to raise the temperature of one pound of water one degree Fahrenheit.


Capacity Market -  Capacity markets can be viewed in several ways. First, in order to ensure that sufficient generation capacity (i.e., the ability to produce electric energy) exists within a region, LSEs are generally required to purchase enough capacity to meet their projected peak load plus a certain level of reserve. To that end, a capacity payment is viewed as a reservation payment to ensure that a generator will be available to provide energy over a specified period of time. Second, to the extent that the revenues generators receive from selling energy and ancillary services do not fully cover their fixed and variable costs, capacity revenues can be viewed as a way of providing generators with that missing money. Finally, capacity payments provide an incentive for new entrants to locate in regions where there is a need for additional resources.

CARIS - Congestion Assessment and Resource Integration Study - CARIS is a biennial study that provides information to market participants, policy makers, and other interested parties for their consideration in evaluating projects designed to address congestion costs identified in the study. The report presents an assessment of historic and projected congestion on the New York State bulk power transmission system and provides an analysis of the potential costs and benefits of relieving that congestion using generic transmission, generation, demand response, and energy efficiency solutions to mitigate the identified congestion.

CEE - Competitive Entry Exemption - A new supplier that is willing to forego contractual support from governmental entities and the incumbent utilities may qualify for a CEE and be exempt from evaluation under the NYISO's BSM measures.

CES - Clean Energy Standard - New York State's plan for reducing greenhouse gas emissions and transitioning to renewable energy. The CES calls for 70 percent of New York's electricity to come from renewable generation sources by 2030. The CES requires load serving entities to help New York meet its clean energy and climate goals by requiring the purchase of renewable energy credits and zero emissions credits.

CONE - Cost of New Entry - The localized levelized embedded costs of a peaking unit, net of the likely projected annual Energy and Ancillary Services revenues of such unit, as determined in connection with establishing the Demand Curve.

CRIS - Capacity Resource Interconnection Service - CRIS is required to be eligible to sell into ICAP markets. Class Year Deliverability Studies are conducted to determine the amount of capacity resources can deliver to any point in its capacity zone.

CRM - Constraint Reliability Margin - The CRM is the "cushion" applied to a transmission line between the lines thermal rating (point at which line becomes to hot/overloads), ie: a 100MW thermal rating with a CRM of 20MW has an 80MW limit. The CRM (usually 20 MW) margin that separates: (a) the actual physical limit of a facility and (b) the limit that is used in the market software. A CRM is used to accountfor differences between physical flows and actual flows that result from loop flows and other un-modeled factors. “Zero-CRM” constraints are constraints for which no CRM is used because there is little or no uncertainty regarding un-modeled factors. A zero-CRM is typically used for facilities that connect generation pockets to the grid because overloads on such facilities can be addressed by small output reductions from the generation facility.

CSPP - Comprehensive System Planning Process - The CRPP adequacy and transmission security of the New York Bulk Power Transmission Facilities once every two years. The CSPP has four components—the local transmission planning process, the reliability planning process, the economic planning process (primarily consisting of CARIS, and the public policy transmission planning process. The CSPP originally took form with the NYISO’s reliability planning process, first approved by the FERC in 2004, and, thereafter, went through several revisions primarily in response to FERC Order No. 890 (adding local transmission and economic planning) and Order No. 1000 (adding public policy planning and a competitive selection process to reliability planning).

CTS - Coordinated Transaction Scheduling - CTS is the market process whereby two neighboring RTOs exchange and use real-time market info to clear market participant's intra-hour external transacations more frequently. As part of the CTS process, when constraints occur at the NY-New England AC Interface, the congestion associated with those constraints may be shared with ISO-NE. Depending on the type and cause of the constraint, the congestion may be allocated to the NYISO Proxy LBMP either 100%, 50%, or 0%. Any congestion not included in the NYISO Proxy LBMP is included in the ISONE Proxy LMP.

CY - Class Year - The NYISO's grouping of projects at similar milestones.


DADRP - Day Ahead Demand Response Program - The NYISO’s DADRP allows NYCA Loads to offer their demand reduction in the Day-Ahead Market to supply Energy. This enables flexible Loads to effectively increase the amount of supply in the market and moderate Energy prices.

DAM - Day-Ahead Market - The ISO Administered Market in which Capacity, Energy and/or Ancillary Services are scheduled and sold Day-Ahead consisting of the Day-Ahead scheduling process, price calculations and Settlements. The Day-Ahead market is a forward market in which hourly Locational Based Marginal Prices (LBMP) are calculated for the next operating day based on generation offers, demand bids, and scheduled bilateral transactions.

DAMAP - Day-Ahead Margin Assurance Payments - A supplemental payment made to an eligible Supplier that buys out of a Day-Ahead Energy, Regulation Service, or Operating Reserves schedule such that an hourly balancing payment obligation offsets its Day-Ahead Margin. Rules for calculating these payments, and for determining Suppliers’ eligibility to receive them, are set forth in Attachment J to this ISO Services Tariff. A DAMAP is available to provide incentives for resources to offer flexibly in the RTM by ensuring the resource will not incur a reduction in their their earned DAM margin when following NYISO instructions. Guarantee the difference between an eligible resource's DAM bid cost and the RTM price when the resource is adversely affected financially by the NYISO dispatch instructions to deviate from their DAM schedule.

DARU - Day-Ahead Reliability Unit - A Day-Ahead committed Resource which would not have been committed but for the request by a Transmission Owner in order to meet the reliability needs of the Transmission Owner’s local system which request was made known to the ISO prior to the close of the Day-Ahead Market.

DCE - DER Coordinator Entity - Aggregator of DER.

DCEA - DCE Aggregation - Aggregation of resources under the DER Coordinator Entity.

DEC - Department of Environmental Conservation - The Department of Environmental Conservation adminsters New York's environmental policies, enforces environmental laws and regulations, performs research, and provides information of environmental subjects. The state agency also serves as the chief advisor to the Governor on state environmental policy and issues.

DER - Distributed Energy Resource - DER is a resource or set of resources -- typically located on an end-use customer’s premises and operated for the purpose of supplying customer electric load -- that seeks to provide NYISO wholesale market services.

DMGC - Dependable Maximum Gross Capability - If DMGC higher than CRIS rights, cap out at CRIS rights. DMGC is a variation of the DMNC and is specific to BTM:NG resources.

DMNC - Dependable Maximum Net Capability Test - The sustained maximum net output of a Generator, as demonstrated by the performance of a test or through actual operation, averaged over a continuous time period as defined in the ISO Procedures. Used to determine ICAP and UCAP ratings.

DPS - Department of Public Service - The Department of Public Service is tasked with affordable, safe, secure, and reliable access access to utility service at just and reasonable rates for New York consumers and businesses. The DPS is the staff of the Public Service Commission.

DSASP - Demand Side Ancillary Services Program - An ISO program that allows qualified DSASP Resources to participate in the ISO’s Day-Ahead and Real-Time Markets for Operating Reserves and Regulation Service in accordance with the ISO Services Tariff and ISO Procedures.


EAS/E&AS - Energy & Ancillary Services - Ancillary Services are services necessary to support the transmission of capacity and energy from generation resources to consumers, while maintaining the reliable operation of New York's transmission system. These services include Regulation and Operating Reserve, Energy Imbalance (using market-based pricing), and the cost-based services of Scheduling, System Control and Dispatch, Voltage Control and Black Start.

EDRP - Emergency Demand Response Program - This is a program designed to reduce load during a declared NYISO emergency, thereby helping to maintain the reliability of the bulk power system. Participation by NYISO customers is voluntary and no penalties are assessed if a customer is not able to respond to the NYISO's call to reduce load. Customers must register for this program and meet minimum qualifications to be accepted into the program. For example, customers must be able to disconnect from the distribution network or reduce load by a measurable and verifiable amount. They must reduce a minimum of 100 kV/Zone and be able to respond within 2 hours of the notice from the NYISO. How do the participants benefit? For an emergency lasting 4 or more hours, participants will receive the higher of $500/MWh or the Real-Time Zonal LBMP during the emergency state. For an emergency lasting less than 4 hours, participants will be paid the prices above for a minimum of 2 hours up to the duration of the event (4 hours).

EFORd - Equivalent Forced Outage Rate on Demand - Represents the portion of time a unit is in demand, but is unavailable due to foced outages. NYISO calculates EFORd for applicable generators based on GADS Data. Forced Outages and derates represent the time when a unit was not in a scheduled outage and not available in whole or in part.

EMS - Energy Management System - The EMS is used by the system operators to monitor the reliable operation of the grid and for situational awareness. It includes applications that monitor load flows and perform contingency analyses, such as security monitor, state estimator, outage monitoring, and automatic generation control.

ERIS - Energy Resource Interconnection Service - Interconnection service study required before resources can provide energy and ancillary services.

ESCO - Energy Service Company - A commercial or non-profit business providing a broad range of energy solutions including designs and implementation of energy savings projects, retrofitting, energy conservation, energy infrastructure outsourcing, power generation and energy supply, and risk management. 

ESPWG - Electric System Planning Working Group - The planning stakeholder forum that provides Market Participant input on the NYISO’s comprehensive planning processes (study assumptions, scenario development, etc.).

ESR - Energy Storage Resources - ESRs are pumped hydroelectric generators, flywheels, and batteries, which can supply electricity to the grid to meet demand, and can withdraw electricity from the grid to alleviate excess supply.


FCA - Fuel Cost Adjustments - FCAs allow generators to submit a fuel type and/or price along with their energy offers. If the FCAs are validated using posted thresholds, the generator’s Incremental Energy and Min Gen Reference Levels are updated to reflect the submitted fuel type and/or price. MMA reviews all FCAs in accordance with the Services Tariff.

FERC - Federal Energy Regulatory Commission - The federal agency that regulates the transmission and wholesale sale of electricity and natural gas in interstate commerce and regulates the transportation of oil by pipeline in interstate commerce.


GADS - Generating Availability Data System - GADS is recognized as a valuable source of reliability information for total unit and major equipment groups and is widely used by industry analysts in a variety of applications. Through GADS, NERC collects information about the performance of electric generating equipment and provides assistance to those researching information on power plant outages. GADS also supports equipment availability analyses and other decision-making processes in the industry. GADS data is also used in conducting assessments of generation resources and improving their performance. GADS is a mandatory industry program for conventional generating units that are 20 MW and larger.

GDA - Generator Deactivation Assessment - Study conducted when a generator announces retirement or mothball status to determine if a Reliability Need will result from the retirement.

GDFC - Generator Deactivation Facilities Charge – The facilities charge for the recovery of the costs of a regulated transmission Generator Deactivation Solution in connection with a Generator Deactivation Reliability Need arising in the Generator Deactivation Process.

GT - Gas Turbine - A turbine driven by expanding hot gases produced by burning fuel.

GW - Gigawatt - 1,000 MW.


HAM - Hour Ahead Market - Market in which bids are submitted at least seventy-five (75) minutes before the dispatch hour to which it applies.


ICAP - Installed Capacity - The NYISO uses an Unforced Capacity (UCAP) methodology to determine the amount of Capacity that each Resource is qualified to supply to the NYCA, and to determine the amount of Capacity that LSEs must procure. The Unforced Capacity methodology estimates the probability that a Resource will be available to serve Load, taking into account forced outages. The term ICAP describes the market as opposed to the product, which is UCAP.

IIFO - ICAP Ineligible Forced Outage - A resource in an IIFO is not qualified to participate in the NYISO Installed Capacity Market and shall be retired if either the CRIS rights for the unit have expired or if the unit has been in an ICAP Ineligible Forced Outage or Mothball Outage for 36 consecutive months.

IPFSWG - Interconnection Projects Facility Studies Working Group - The IPFSWG is a working group for Class Year developers and interested parties that reviews and provides input on a Class Year facilities study.

IRM - Installed Reserve Margin - Capacity above firm system demand required to provide for equipment forced and scheduled outages and transmission capability limitations


JOA - Joint Operating Agreement - Operating agreement between NYISO and neighboring operating region.


kW - Kilowatt - A measurement of electric power equal to one thousand watts. Electric power capacity of one kW is sufficient to power 10 100-watt light bulbs, or about one average home.

kWh - Kilowatt Hour - A measurement of energy and is equal to the energy produced by a one kilowatt plant in one hour. (Note: A typical electric consumer in New York State uses 500 kWh per month of electricity.)


LBMP - Locational Based Marginal Price - A methodology where the price of energy at each location in the NYS Transmission System/NYCA is equivalent to the cost to supply the next increment of Load at that location. Energy + Loss + Congestion = LBMP.

LCR - Locational Minimum Installed Capacity Requirements - The LCR analysis is an optimization process for the NYCA system to meet the LOLE reliability criteria by setting minimum requirements for each of the defined localities.

LDC - Local Distribution Company - A legal entity engaged primarily in the retail sale and/or delivery of natural gas through a distribution system .

LOLE - Loss of Load Expectation - The probability of disconnecting firm load not more than once in 10 years. The NYSRC establishes the IRM requirement for the NYCA such that the probability (or risk) of disconnecting any firm load due to resource deficiencies shall be, on average, not more than once in ten years. Compliance with this criterion is evaluated probabilistically, such that the LOLE of disconnecting firm load due to resource deficiencies shall be, on average, no more than 0.1 days per year.

LSE - Load Serving Entity - Most often a utility or electric company. LSEs are market participants that are required to satisfy capacity requirements through self-supply, bilateral transactions, or through purchased capacity in the ICAP auctions to meet load plus any excess capacity determined by the ICAP Spot Market Auction.

LTP - Local Transmission Plan - Plan and timeline by local Transmission Owner for upgrading system.


MARS - Multi-Area Reliability Simulation - General Electric computer program used for calculating the probabilities of generator unit outages, in conjunction with load and transmission representations, to determine the days per year of expected resource capacity shortages. MARS is used to set the IRM and LCRs.

MC - Management Committee - The MC is a standing committee of the NYISO which recommends tariff changes to the Board of Directors, reviews the NYISO’s annual budget, recommends candidates to fill vacancies on the Board of Directors, and supervises the activity of all other committees.

MMA - Market Mitigation & Analysis - Internal NYISO department responsible for administering market mitigation measures, responding to data requests, developing Reference Levels and Load Pocket Thresholds.

MST - Market Administration and Control Area Services Tariff - The NYISO MST sets forth the provisions applicable to the services provided by the ISO related to its administration of competitive markets for the sale and purchase of Energy and Capacity and for the payments to Suppliers who provide Ancillary Services to the ISO in the ISO Administered Markets (Market Services) and the ISO’s provision of Control Area Services, including services related to ensuring the reliable operation of the NYS Power System. The Tariff addresses the Market Services and the Control Area Services provided by the ISO, and the terms and conditions under which those services are provided. Market Services are addressed in Article 4 of the Tariff, and Control Area Services are addressed in Article 5 of the Tariff.

MW - Megawatt - A megawatt is a unit for measuring power that is equivalent to one million watts, or 1,000 kilowatts.

MWh - Megawatt Hour - A megawatt hour is equal to 1,000 kilowatt hours (Kwh). It is equal to 1,000 kilowatts of electricity used continuously for one hour.


NAAQS - National Ambient Air Quality Standards - Established under the Clean Air Act, NAAQS have been set for six principal pollutants known as criteria pollutants. These are carbon monoxide, lead, nitrogen dioxide, particulate matter (airborne suspensions of extremely small solid or liquid particles), sulfur oxides, and ground-level ozone. Established in 1979 as a 1-hour standard at 0.12 parts per million (ppm); Revised in 1997, changing from a 1-hour to 8-hour standard at 0.08 ppm; Revised in 2008, lowering to 0.075 ppm; and Revised in 2015, lowering to 0.070 ppm.

NERC - North American Electric Reliability Council - NERC is a not-for-profit international regulatory authority whose mission is to assure the reliability and security of the bulk power system in North America. NERC develops and enforces Reliability Standards; annually assesses seasonal and long‐term reliability; monitors the bulk power system through system awareness; and educates, trains, and certifies industry personnel. NERC’s area of responsibility spans the continental United States, Canada, and the northern portion of Baja California, Mexico. NERC is the electric reliability organization (ERO) for North America, subject to oversight by the Federal Energy Regulatory Commission (FERC) and governmental authorities in Canada. NERC's jurisdiction includes users, owners, and operators of the bulk power system, which serves more than 334 million people.

NYISO - New York Independent System Operator - An independent non-profit that is federally regulated. The NYISO is charged with operating New York's bulk electricity grid, administering the state's wholesale electricity markets, and providing comprehensive reliability planning for the state's bulk electricity system.

NYSERDA - New York State Energy Research and Development Authority - A New York State agency promoting energy efficiency and the use of renewable energy sources. NYSERDA works with stakeholders including residents, business owners, developers, community leaders, local governments, utilities, and investors.

NYSRC - New York State Reliability Council - A not-for-profit entity whose mission is to promote and preserve the reliability of electric service on the New York State Power System by developing, maintaining, and, from time-to-time, updating the Reliability Rules which shall be complied with by the NYISO and all entities engaging in electric transmission, ancillary services, energy and power transactions on the New York State Power System. 


OATT - Open Access Transmission Tariff - Sets forth the provisions applicable for transmission service.

OC - Operating Committee - The OC is a standing committee of the NYISO created pursuant to the ISO Agreement, which coordinates operations, develops procedures, evaluates proposed system expansions and acts as a liaison to the NYSRC.

OFO - Operational Flow Order - Order from the NYISO/LDC for generators to stick to their schedule for gas supply purposes. Does not limit generator gas use, just what generators can purchase.

OOM Dispatch – Out-of-Merit Dispatch - The designation of Resources committed and/or dispatched by the ISO at specified output limits for specified time periods to meet Load and/or reliability requirements that differ from or supplement the ISO’s security constrained economic commitment and/or dispatch.

OOM Generation - Out-of-Merit Generation - Generators producing at a different level of output than they would produce in a dispatch to meet Load which was not security constrained. Out-of-Merit Generation occurs to maintain system reliability or to provide Ancillary Services.

OSW - Offshore Wind Standard - Established by the PSC to maximize the value potential of new offshore wind resources by jumpstarting the industry in New York State. The OSW Standard includes an initial procurement of solicitations and an obligations on LSEs to obtain ORECs.

ORECs - Offshore Wind Renewable Energy Credits - An OREC represents one MWh of electricity generated from offshore wind resources and consumed by retail customers in New York State. LSEs will purchase ORECs from NYSERDA. ORECs are intended to provide financial support for investments in offshore wind energy.


PAR - Phase Angle Regulator - A specialized form of transformer used to control the flow of real power on three-phase electricity transmission networks. Where parallel circuits with different capacity exist between two points in a transmission grid (for example, an overhead line and an underground cable), direct manipulation of the phase angle allows control of the division of power flow between the paths, preventing overload. Provide a means of relieving overloads on heavily laden circuits and re-routing power via more favorable paths.

PPA - Power Purchase Agreement - The contract entered into by an independent power producer and an electric utility. The power purchase agreement specifies the terms and conditions under which electric power will be generated and purchased. Power purchase agreements require the independent power producer to supply power at a specified price for the life of the agreement.

PPTPP - Public Policy Transmission Planning Process - As part of each PPTPP cycle, the NYISO solicits and submits to the New York Public Service Commission proposed transmission needs being driven by Public Policy Requirements for review and potential adoption. Projects evaluated and selected by the NYISO as the most efficient and cost effective are eligible for cost recovery under the NYISO's tariff, in compliance with FERC Order 1000.

PSC - Public Service Commission - The PSC regulates New York State's electric, gas, steam, telecommunications, and water utilities. The Commission is bipartisan and is charged by law with the responsibility for setting rates and ensuring that adequate service is provided by New York's utilities. In addition, the Commission exercises jurisdiction over the siting of major gas and electric transmission facilities and has responsibility for ensuring the safety of natural gas and liquid petroleum pipelines. The Commission consists of up to five members, each appointed by the Governor and confirmed by the State Senate for a term of six years or to complete an unexpired term of a former Commissioner.




RECs - Renewable Energy Credits - RECs are purchased by New York State utilities to invest in new renewable generation resources to serve their retail customers as part of the Clean Energy Standard.

RGGI - Regional Greenhouse Gas Initiative - The first mandatory market-based program in the United States to reduce greenhouse gas emissions, RGGI is a cooperative effort among the states of Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New York, Rhode Island, and Vermont to cap and reduce carbon dioxide emissions from the power sector.

RNA - Reliability Needs Assessment - A biennial study that assesses the resource adequacy, and transmission security, of the NYCA Bulk Power Transmission Facilities for a defined study period consisting of 10 years forward.

ROFR - Right of First Refusal - Under ROFR, utilities have the right to build, maintain, and own transmission lines within their service territory. The project would go into competitive bidding if the utility declines it.

ROR Hydro - Run of River Hydro

ROS - Rest of State - For purposes of the ICAP market, all areas of the NYCA excluding Load Zones G-J and K.

ROW - Right of Way - Legal right of way, established by usage or grant, to pass along a specific route. In this context, ROW is the routes, usually under the control of a Utility, used for HV transmission lines.

RTC - Real-Time Commitment - After the day-ahead schedule is published and no later than 75 minutes before each hour, customers may submit real-time bids into the RTC program for real-time evaluation. RTC will: make binding unit commitment and de-commitment decisions for the periods beginning 15 minutes (in the case of resources that can respond in ten minutes) and 30 minutes (in the case of resources that can respond in thirty minutes) after the scheduled posting time of each RTC run; provide advisory commitment information for the remainder of the two-and-a-half hour optimization period; and produce binding schedules for external transactions. RTC co-optimizes to solve simultaneously for all load, operating reserves and regulation service requirements and to minimize the total as-bid production costs over its optimization timeframe.

RTM - Real-Time Market - The Real-Time market is a spot market in which current LBMPs are calculated at five-minute intervals based on actual grid operating conditions.


SCED - Security Constrained Economic Dispatch - Optimally dispatches resources to meet load while respecting transmission constraints every five minutes.

SCR - Special Case Resource - The NYISO's SCR program provides an opportunity for Local Generators and demand resources with interruptible load to receive payments for Capacity and Energy.

SCR - Selective Catalytic Reduction - Selective Catalytic Reduction (SCR) is an advanced active emissions control technology system that injects a liquid-reductant agent through a special catalyst into the exhaust stream of a diesel engine. The reductant source is usually automotive-grade urea, otherwise known as Diesel Exhaust Fluid (DEF). The DEF sets off a chemical reaction that converts nitrogen oxides into nitrogen, water and tiny amounts of carbon dioxide (CO2), natural components of the air we breathe, which is then expelled through the vehicle tailpipe. SCR technology is designed to permit nitrogen oxide (NOx) reduction reactions to take place in an oxidizing atmosphere. It is called "selective" because it reduces levels of NOx using ammonia as a reductant within a catalyst system. The chemical reaction is known as "reduction" where the DEF is the reducing agent that reacts with NOx to convert the pollutants into nitrogen, water and tiny amounts of CO2. The DEF can be rapidly broken down to produce the oxidizing ammonia in the exhaust stream. SCR technology alone can achieve NOx reductions up to 90 percent.

SCUC - Security Constrained Unit Commitment - The NYISO’s SCUC software is a multi-period, security constrained unit commitment process that co-optimizes to solve simultaneously for Load, Operating Reserves, and Regulation Service on a least as-bid production cost basis over a twenty-four hour optimization period. Evaluates day-ahead offers, identifies unit commitments & financially binding schedules for generators and bilateral transactions for twenty-four, one hour intervals.

SDU - System Delivery Upgrade - Upgrades to make modifcations or additions to the existing transmisison sytem that are required for a proposed project to connect reliably to the system in a manner that meets NYISO standards.

SGIP - Small Generator Interconnection Procedures - New York State SIR govern the interconnection of resources when: (1) the developer is interconnecting to portions of the distribution system other than “FERC-jurisdictional distribution” and (2) the resource is less than or equal to 5 MW.

SRE - Supplemental Resource Evaluation - A determination of the least cost selection of additional Generators, which are to be committed, to meet: (i) changed or local system conditions for the Dispatch Day that may cause the Day-Ahead schedules for the Dispatch Day to be inadequate to meet the reliability requirements of the Transmission Owner’s local system or to meet Load or reliability requirements of the ISO; or (ii) forecast Load and reserve requirements over the six-day period that follows the Dispatch Day. Called whenever there are not enough generation bids provided to serve the forecasted load or if system conditions change that would cause the original dispatch to be insufficient to serve load. This does not necessarily translate to an emergency state. SRE's may be called for the DAM or HAM market. Bids are selected based upon the lowest cost solution and payments are made via the calculated LBMP's at the appropriate gen bus. In an emergency state an SRE may be called as well as a call to participants in the EDRP program.

SRP - System Restoration Plan - Plan to restore electric system in event of blackout.

SSM - Supplier-Side Mitigation - Supplier-side Mitigation measures are placed on any capacity provider in Zones J and G-J deemed to be a "Pivotal Supplier." Any entity deemed a Pivotal Supplier is required to offer all capacity under its control at the time of the Spot auction at the identified Reference Price. This measure is designed to prevent that entity from witholding capacity in order to raise prices by creasting an artificial scarcity.


TCC -Transmission Congestion Contracts - A TCC is a financial instrument obtained through a NYISO auction or other source that represents the right to collect or obligation to pay DAM congestion rents going forward in time.

TO - Transmission Owner - Market Participants that are required to satisfy capacity requirements through self-supply, bilateral transactions, or through purchased capacity in the ICAP auctions to meet load plus any excess capacity determined by the ICAP Spot Market Auction.

TOP - Transmission Operator Planner - Develops a plan (generally one year and beyond) for the resource adequacy of its specific loads.

TPAS - Transmission Planning Advisory Subcommittee - The TPAS advises the OC and provides support to the NYISO staff in regard to transmission planning matters including transmission system reliability, expansion and interconnection.

TOTS - Transmission Owners Transmission Solutions - Transmission solutions identified and implemented by TOs as part of the Indian Point Contingency Plan proceedings conducted by the State in anticipation for the potential future closing of the Indian Point Energy Center.


UCAP - Unforced Capacity - The measure by which Installed Capacity Suppliers will be rated, in accordance with formulae set forth in the NYISO Procedures, to quantify the extent of their contribution to satisfy the NYCA Minimum Installed Capacity Requirement, and which will be used to measure the portion of that NYCA Minimum Installed Capacity Requirement for which each LSE is responsible. UCAP is ICAP adjusted for performance through GADS data to account for the historic availability of suppliers. It is calculated every Capability Period for the NYCA and Localities.

UDRs - Unforced Capacity Deliverability Rights - Rights, as measured in MWs, associated with (i) new incremental controllable transmission projects, and (ii) new projects to increase the capability of existing controllable transmission projects that have UDRs, that provide a transmission inteface to a Locality. When combined with UCAP which is located in an External Control Area or non-constrained NYCA region either by contract or ownership, and which is deliverable to the NYCA interface in the Locality in which the UDR transmission facility is electrically located, UDRs allow such UCAP to be treated as if it were located in the Localitym thereby contributing to an LSE's LCR.

UOL - Upper Operating Limit - The upper operating limit that a Generator, except for the Generator of a BTM:NG Resource, indicates it expects to be able to reach, the upper operating limit that a BTM:NG Resource indicates it expects to be able to inject into the grid after serving its Host Load and subject to its Injection Limit, or the maximum amount of demand that a Demand Side Resource expects to be able to reduce, at the request of the ISO during extraordinary conditions. Each Resource shall specify a UOL in its bids that shall be equal to or greater than its stated Normal Upper Operating Limit.




Wheeling - transmission or movement of power over transmission lines. Electric power can be wheeled from a generating plant directly to a wholesale or retail consumer, or it can be wheeled to the consumer through the interconnected transmission facilities of one or more intermediate utilities.






ZECs - Zero-Emissions Credits - ZECs are purchased by New York State utilities for the generation by a nuclear electric generating facility as part of the Clean Energy Standard.