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Glossary - e

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
EAF Equivalent Availability Factor
EAL Estimated Aggregate Liability
EC Electric Cooperative
ECI Element Competitiveness Index
EDI Electronic Data Interchange
EEA Energy Emergency Alert
EFT Electronic Funds Transfer
EILS Emergency Interruptible Load Service
EMMS Energy and Market Management System
EMS Energy Management System
EPRI Electric Power Research Institute
EPS ERCOT Polled Settlement
ERCOT

Electric Reliability Council of Texas
ERCOT Board The Board of Directors of the Electric Reliability Council of Texas, Inc.
ESI ID Electric Service Identifier
Electric Cooperative (EC)
  1. A corporation organized under the Electric Cooperative Corporation Act, TEX. UTIL. CODE ANN. ch 161 (Vernon 1998 & Supp. 2007);
  2. A corporation organized as an electric cooperative in a state other than Texas that has obtained a certificate of authority to conduct business in Texas; or
  3. A successor to an electric cooperative created before June 1, 1999 under a conversion plan approved by a vote of the members of the electric cooperative, regardless of whether the successor later purchases, acquires, merges with, or consolidates with other electric cooperatives.
Electric Reliability Council of Texas, Inc. (ERCOT) The organization approved by the Federal Energy Regulatory Commission (FERC) to perform the electric reliability organization functions described in the Electricity Modernization Act of 2005, 16 U.S.C. § 824o (2005).
Electric Reliability Organization The organization approved by the Federal Energy Regulatory Commission (FERC) to perform the electric reliability organization functions described in the Electricity Modernization Act of 2005, 16 U.S.C. § 824o (2005).
Electric Service Identifier (ESI ID) The basic identifier assigned to each Service Delivery Point used in the registration and settlement systems managed by ERCOT or another Independent Organization.
Electrical Bus
  1. A physical transmission element defined in the Network Operations Model that connects, using breakers and switches, one or more:

    1. Loads;
    2. Lines;
    3. Transformers;
    4. Generators;
    5. Capacitors;
    6. Reactors;
    7. Phase shifters; or
    8. Other reactive control devices to the ERCOT Transmission Grid where there is negligible impedance between the connected Transmission Elements.

  2. All Electrical Buses are designated by ERCOT and TSPs for modeling the electrical topology of the ERCOT Transmission Grid.
Electrically Similar Settlement Points

Two or more distinct Settlement Points that are either mapped to the same electrical location in a market model or are mapped to locations that are connected by a transmission element with a reactance of less than 0.0005 per unit and a rating of more than 9000 MVA.Two or more distinct Settlement Points that are either mapped to the same electrical location in a market model or are mapped to locations that are connected by a transmission element with a reactance of less than 0.0005 per unit and a rating of more than 9000 MVA.
Eligible Transmission Service Customer A Transmission and/or Distribution Service Provider (TDSP) (for all uses of its transmission system), or any electric utility, MOU, EC, power generation company, CR, REP, federal power marketing agency, exempt wholesale generator, Qualifying Facility (QF), Independent Power Marketer, or other Entity that the PUCT has determined to be an Eligible Transmission Service Customer.
Emergency Base Point The target MW output level for a Resource that is selected by ERCOT during an Emergency Condition.
Emergency Condition An operating condition in which the safety or reliability of the ERCOT System is compromised or threatened, as determined by ERCOT, or that is the result of a failure of the SCED process.
Emergency Interruptible Load Service (EILS) A special emergency service consistent with subsection (a) of P.U.C. SUBST. R. 25.507, Electric Reliability Council of Texas (ERCOT) Emergency Interruptible Load Service (EILS), used during an Energy Emergency Alert (EEA) Level 2 to reduce Load and assist in maintaining or restoring ERCOT System frequency. EILS is not an Ancillary Service.
Emergency Interruptible Load Service (EILS) Contract Period A time frame during which ERCOT may procure EILS in an amount no greater than 1,000 MW.
Emergency Interruptible Load Service (EILS) Load A Load or aggregation of Loads that is contracted to provide EILS.
Emergency Interruptible Load Service (EILS) Self-Provision The act by a QSE to meet its Load Ratio Share (LRS) of the total EILS procurement by designating Load to act as an EILS Load. A QSE self-providing EILS shall submit EILS offers at a price of zero dollars.
Emergency Interruptible Load Service (EILS) Time Period Blocks of hours in an EILS Contract Period in which EILS Loads are contractually committed to provide EILS. EILS Time Periods are specific to an EILS Contract Period and shall be defined by ERCOT in the Request for Proposal for that EILS Contract Period.
Emergency Notice The fourth of four possible levels of communication issued by ERCOT in anticipation of a possible Emergency Condition, detailed in Section 6.5.9, Emergency Operations.
Emergency Ramp Rate

The maximum rate of change in MW per minute of a Resource to provide Responsive Reserve (RRS) that is deployed by ERCOT and that is provided to ERCOT in up to ten segments, each represented by a single MW per minute value (across the capacity of the Resource), which describes the available rate of change in output for the given range (between High Sustained Limit (HSL) and Low Sustained Limit (LSL)) of the output of a Resource. In Real-Time SCED Dispatch, the Emergency Ramp Rate is telemetered by the QSE to ERCOT and represents the total capacity (in MW) that the Resource can change from its current actual generation within the next five minutes divided by five.
Emergency Rating See Rating
Emergency Short Supply The condition wherein ERCOT experiences an insufficient amount of bids in any Ancillary Services market, as described in Section 6.
Energy Emergency Alert (EEA) An orderly, predetermined procedure for maximizing use of available Resources and, only if necessary, curtailing load during an Emergency Condition while providing for the maximum possible continuity of service and maintaining the integrity of the ERCOT System.
Energy Imbalance Service An Ancillary Service that is provided when a difference occurs between the scheduled and the actual delivery of energy in Real-Time.
Energy Offer Curve A proposal to sell energy at a Settlement Point at a monotonically increasing price with increasing quantity.
Energy Trade A QSE-to-QSE financial transaction that transfers responsibility for energy between a buyer and a seller at a Settlement Point.
Entity Any natural person, partnership, municipal corporation, cooperative corporation, association, governmental subdivision, or public or private organization.
ERCOT Polled Settlement (EPS) Meter Any meter polled directly by ERCOT for use in the Settlement of the market.
ERCOT Region The power region, as defined in P.U.C. SUBST. R. 25.5, Definitions, represented by the ERCOT Control Area.
ERCOT System The interconnected power system that is under the jurisdiction of the PUCT and that is not synchronously interconnected with either the Eastern Interconnection or the Western Electricity Coordinating Council.
ERCOT System Demand The sum of all power flows, in MW, on the DC Ties and from Generation Resources metered at the points of their interconnections with the ERCOT System at any given time.
ERCOT Transmission Grid All Transmission Facilities that are part of the ERCOT System.