Glossary - M

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


Term/Acronym Definition
MCPC Market Clearing Price for Capacity
MDAS Meter Data Acquisition System
MIS Market Information System
MMBTU Million British Thermal Units
MOU Municipally Owned Utility
MPC Maximum Power Consumption
MRA Must-Run Alternative
MRE Meter Reading Entity
MTLF Mid-Term Load Forecast
MVA Megavolt Ampere
MVAR Mega Volt-Amperes reactive
MW Megawatt
MWH Megawatt Hour
Maintenance Outage See Outage
Make-Whole Charge A charge made by ERCOT to a QSE for a Resource to recapture all or part of the revenues received by a QSE that exceed the Make-Whole Payment for a Resource.

Make-Whole Payment

A payment made by ERCOT to a Qualified Scheduling Entity (QSE) for a Resource to reimburse a QSE for allowable startup and minimum energy costs of a Resource not recovered in energy revenue when a Resource is committed by Reliability Unit Commitment (RUC) and the QSE has not elected to opt out of RUC Settlement, or when a Resource is committed by the Day-Ahead Market (DAM).

Mandatory Installation Threshold A peak demand greater than 700 kW (or 700 kVA).
Market Clearing Price for Capacity (MCPC) The hourly price for Ancillary Service capacity awarded in the DAM or a SASM.

Market Information System (MIS)

An electronic communications interface established and maintained by ERCOT that provides a communications link to the public and to Market Participants, as a group or individually.

Market Information System (MIS) Certified Area
The portion of the MIS that is available only to a specific Market Participant.

Market Information System (MIS) Public Area
The portion of the MIS that is available to the public.

Market Information System (MIS) Secure Area
The portion of the MIS that is available only to registered Market Participants.

Market Notice A notice required by the Protocols or any Other Binding Document, or at ERCOT’s discretion, regarding market-relevant information that shall be communicated through ERCOT publicly-subscribed electronic distribution channels.
Market Participant An Entity, other than ERCOT, that engages in any activity that is in whole or in part the subject of these Protocols, regardless of whether that Entity has signed an Agreement with ERCOT. Examples of such an Entity include but are not limited to the following: LSE, QSE, TDSP, CRR Account Holder, Resource Entity, IMRE and REC Account Holder.
Market Segment The segments defined in Article 2 of the ERCOT Bylaws.
Mass Transition The transition of ESI IDs from one CR to a Provider of Last Resort (POLR) or designated CR, or from one TDSP to another TDSP, in a quantity or within a timeframe identified by Applicable Legal Authority.
Master Qualified Scheduling Entity (QSE) see Qualified Scheduling Entity (QSE)
Maximum Power Consumption (MPC) For a Load Resource, the limit established by the QSE, continuously updated in Real-Time, that describes the maximum sustained power consumption of a Load Resource. The MPC shall be a positive number in MW.

Messaging System

The ERCOT-to-QSE communications system used to send Real-Time notices and Dispatch Instructions to QSEs.

Meter Data Acquisition System (MDAS) The system used to obtain revenue quality meter data from EPS meters and Settlement Quality Meter Data from TSPs and DSPs for Settlement and to populate the DAS and Data Archive.
Meter Reading Entity (MRE) A TSP or DSP that is responsible for providing ERCOT with ESI ID level consumption data as defined in Section 19, Texas Standard Electronic Transaction. In the case of an EPS Meter or ERCOT-populated ESI ID data (such as Generation Resource site Load), ERCOT will be identified as the MRE in ERCOT systems.
Metering Facilities Revenue Quality Meters, instrument transformers, secondary circuitry, secondary devices, meter data servers, related communication Facilities and other related local equipment intended to supply ERCOT settlement quality data.
Minimum Point-to-Point (PTP) Option Bid Price

A value of $0.010 representing the minimum price that can be submitted into the CRR Auction for a PTP Option bid.

Minimum Reservation Price The lowest price that a seller is willing to accept.
Minimum-Energy Offer An offer for the costs incurred by a Resource in producing energy at the Resource’s LSL expressed in $/MWh.
Mitigated Offer Cap An upper limit on the price of an offer as detailed in Section, Mitigated Offer Cap.
Mitigated Offer Floor A lower limit on the price of an offer as detailed in Section, Mitigated Offer Floor.

Mitigation Plan

A set of pre-defined manual actions to execute post-contingency to address voltage issues or reduce overloading on one or more given, monitored Transmission Facilities to below their Emergency Rating with restoration of normal operating conditions within two hours. A Mitigation Plan must be implementable and may include transmission switching and Load shedding. Mitigation Plans shall not be used to manage constraints in Security-Constrained Economic Dispatch (SCED).

Mothballed Generation Resource

A Generation Resource for which a Resource Entity has submitted a Notification of Suspension of Operations, for which ERCOT has declined to execute an RMR Agreement, and which has not been decommissioned and retired.

Move-In Request A request submitted by a CR on behalf of a Customer to initiate service at a Premise with the requesting CR.
Move-Out Request A request submitted by a CR on behalf of a Customer to terminate service at a Premise with the requesting CR.
Municipally Owned Utility (MOU) A utility owned, operated, and controlled by a nonprofit corporation, the directors of which are appointed by one or more municipalities, or a utility owned, operated, or controlled by a municipality.