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Glossary

For your convenience, this page contains an alphabetically organized list of terms, definitions and common acronyms used in the electric utility industry.

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Term/Acronym

Definition
AAA American Aribtration Association
ACE Area Control Error
ACH Automated Clearing House
ACL Available Credit Limit
ADR Alternative Dispute Resolution
AEIC Association of Edison Illuminating Companies
AGC Automatic Generation Control
AGR Aggregate Generation Resource
AIL Aggregate Incremental Liability
ALA Applicable Legal Authority
AML Adjusted Metered Load
AMS Advanced Metering System
ANSI ASC X12 American National Standards Institute Accredited Standards Committee X12
AREP Affiliated Retail Electric Provider
ARR Adjusted RPS Requirement
AVR Automatic Voltage Regulator
Adjusted Metered Load (AML) Retail Load usage data that has been adjusted for Unaccounted for Energy (UFE), Transmission Losses, Distribution Losses, and Direct Current Tie (DC Tie) exports (except for the Oklaunion Exemption).
Adjusted Static Models Load Profiles that are generated from statistical models that are based on static historical Load data, and adjusted for conditions of the day (e.g., weather, Season, etc.).
Adjustment Period For each Operating Hour, the time between 1800 in the Day-Ahead up to the start of the hour before that Operating Hour.
Advanced Meter Any new or appropriately retrofitted meter that functions as part of a system that includes such meters and the associated hardware, software, and communications devices, that collects time-differentiated energy usage, and that is deployed pursuant to P.U.C. SUBST. R. 25.130, Advanced Metering.
Advanced Metering System (AMS) A system, including Advanced Meters and the associated hardware, software, and communications devices, that collects time-differentiated energy usage and is deployed pursuant to P.U.C. SUBST. R. 25.130, Advanced Metering.
Advisory The second of four possible levels of communication issued by ERCOT in anticipation of a possible Emergency Condition, detailed in Section 6.5.9, Emergency Operations.
Affiliate
  1. An Entity that directly or indirectly owns or holds at least 5% of the voting securities of another Entity; or
  2. An Entity in a chain of successive ownership of at least 5% of the voting securities of another Entity; or
  3. An Entity that has at least 5% of its voting securities owned or controlled, directly or indirectly, by another Entity; or
  4. An Entity that has at least 5% of its voting securities owned or controlled, directly or indirectly, by an Entity who directly or indirectly owns or controls at least 5% of the voting securities of another Entity or an Entity in a chain of successive ownership of at least 5% of the voting securities of another Entity; or
  5. A person who is an officer or director of another Entity or of a corporation in a chain of successive ownership of at least 5% of the voting securities of an Entity; or
  6. Any other Entity determined by the Public Utility Commission of Texas (PUCT) to be an Affiliate.
Aggregate Generation Resource (AGR) A Generation Resource that is an aggregation of non-wind generators, each of which is less than 10 MW in output, which share identical operational characteristics and are interconnected at the same POI and located behind the same Generator Step-Up (GSU) transformer (with a high-side voltage greater than 60 kV).
Agreement A signed written agreement between ERCOT and a Market Participant using one of the standard form agreements in Section 22, Attachments, including those agreements containing changes to the standard form, which changes have been approved by the ERCOT Board.
All-Inclusive Generation Resource A term used to refer to both a Generation Resource and a Non-Modeled Generator.
All-Inclusive Resource A term used to refer to a Generation Resource, Load Resource and a Non-Modeled Generator.
Alternative Dispute Resolution (ADR) Procedures, outlined in Section 20, Alternative Dispute Resolution Procedure, for settling disputes by means other than litigation.
Ancillary Service A service necessary to support the transmission of energy to Loads while maintaining reliable operation of the Transmission Service Provider’s (TSP’s) transmission system using Good Utility Practice.
Ancillary Service Capacity Monitor A set of processes described in Section 8.1.1.3, Ancillary Service Capacity Compliance Criteria, to determine the Real-Time capability of Resources to provide Ancillary Service.
Ancillary Service Obligations For each Ancillary Service, a Qualified Scheduling Entity’s (QSE’s) ERCOT-allocated share of total ERCOT System needs for that Ancillary Service.
Ancillary Service Offer An offer to supply Ancillary Service capacity in the Day-Ahead Market (DAM) or a Supplemental Ancillary Service Market (SASM).
Ancillary Service Resource Responsibility The MW of an Ancillary Service that each Resource is obligated to provide in Real-Time rounded to the nearest MW.
Ancillary Service Schedule The MW of each Ancillary Service that each Resource is providing in Real-Time and the MW of each Ancillary Service for each Resource for each hour in the Current Operating Plan (COP).
Ancillary Service Supply Responsibility The net amount of Ancillary Service capacity that a QSE is obligated to deliver to ERCOT, by hour and service type, from Resources represented by the QSE.
Ancillary Service Trade A QSE-to-QSE transaction that transfers an obligation to provide Ancillary Service capacity between a buyer and a seller.
Area Control Error (ACE) A calculation of the MW correction needed to control the actual system frequency to the scheduled system frequency.
Authorized Representative The person(s) designated by an Entity during the registration process in Section 16, Registration and Qualification of Market Participants, who is responsible for authorizing all registration information required by ERCOT Protocols and ERCOT business processes, including any changes in the future, and will be the contact person(s) between the registered Entity and ERCOT for all business matters requiring authorization by ERCOT.
Automatic Voltage Regulator (AVR) A device on a Generation Resource or a control system at the Facility of a Generation Resource used to automatically control the voltage to an established voltage set point.
Availability Plan An hourly representation of availability of Reliability Must-Run (RMR) Units or Synchronous Condenser Units, or an hourly representation of the capability of Black Start Resources as submitted to ERCOT by 0600 in the Day-Ahead by QSEs representing RMR Units, Synchronous Condenser Units or Black Start Resources.