Transmission Must Run Services (TMR)
TMR is generation that is required to be online and operating at specific levels in particular parts of the Alberta Integrated Electrical System (AIES) to compensate for insufficient local transmission infrastructure relative to local demand. TMR is in place to ensure system reliability until adequate transmission infrastructure is built. In the long-term the requirement for TMR will diminish and eventually be eliminated as the AIES is enhanced and upgraded with new transmission lines.
The AESO currently has contracts in place with various generators to provide this service. Given the location-specific nature of TMR, only specific units in Alberta are needed to provide TMR. The AESO contracts with these units when long-term requirements for TMR are identified.
TMR Resources
AESO Ancillary Services Procurement Process
This document outlines the AESO’s procedure for the procurement of ancillary services
Operating Policies & Procedures (OPP’s) for TMR
The following OPPs make reference to TMR – a brief description of each OPP is listed below. To access each specific OPP please view the OPP table of contents. You will be able navigate from the table of contents to the specific OPPs listed below.
OPP 501: Northwest Area Operation
This OPP defines the policies and procedures required to operate the northwestern area of the AIES, including transmission must-run (TMR) generation and voltage management.
OPP 510: Calgary Area Operation
This OPP defines the policies and procedures for managing Calgary area dynamic reactive reserve including the dispatching of Calgary area TMR contracted generators and the directing of Calgary area generators that do not have TMR contracts.
Compensation for Unforeseeable Transmission Must Run Services - Article 11 of the AESO Tariff
This document explains how a generator that is directed to provide TMR that does not have a TMR contract is compensated.
Dispatch Down Service (DDS)
In order to compensate for the effect that TMR generators may have on pool price, the AESO uses a service called Dispatch Down Service (DDS) whereby eligible generators receive a payment for reducing generation levels or dispatching off in proportion to the amount of TMR online when the system marginal price is less than a TMR “reference price”. ISO Rule 6.3.6 provides a detailed description of DDS and can be found here.