AESO Practices for System Access Service May 31, 2013
Table of Contents 1 Purpose... 3 2 Introduction... 3 3 Practices for System Access Service... 4 3.1 Conditions for System Access Service... 4 3.2 Rationale for Conditions for System Access Service... 5 4 Application of the Practices for System Access Service... 6 4.1 Constraints Managed Under Abnormal Operating Conditions... 7 4.2 Constraints Managed by a Connection Remedial Action Scheme... 7 4.3 Constraints Under Normal Operating Conditions... 8
1 Purpose This document describes the practices for system access service that the AESO uses when planning the transmission system and when providing a reasonable opportunity for system access to generation and load market participants ( Practices ). The AESO has incorporated these Practices within the AESO s Connection Process. The AESO may amend these Practices from time to time and will advise market participants of any amendments via the AESO Stakeholder Newsletter. The AESO will consistently apply these Practices to ensure that the AESO meets its legislative obligations and the intent of the Alberta government s policy documentation. 2 Introduction The Electric Utilities Act, Transmission Regulation and Alberta government policy documents, including the Transmission Development Policy, establish the Alberta transmission and market framework and impose obligations that the AESO fulfils through ISO rules, Alberta Reliability Standards, practices and processes. Relevant to these Practices are the following obligations: a) the AESO is the sole provider of system access service on the transmission system 1, and must provide such access in a timely 2, efficient, reliable and non-discriminatory manner 3 that gives all market participants wishing to exchange electrical energy and ancillary services a reasonable opportunity to do so 4 ; b) the AESO is required to manage transmission constraints 5 ( constraints ), and provides system access service in a manner that is consistent with section 15(1) of the Transmission Regulation; c) the AESO has the duty to: i) plan the capability of the transmission system to meet the needs of market participants 6, ii) direct the safe reliable and economic operation of the Alberta interconnected electric system 7, and iii) facilitate the operation of the market in a fair, efficient and openly competitive manner that gives all market participants a reasonable opportunity to participate 8. When a market participant requests system access service, the AESO seeks to determine and clearly communicate anticipated constraints. In order to resolve identified constraints, the AESO proposes transmission capacity enhancements when and where appropriate. All new and existing market participants need to be aware of and consider constraints and, in particular, the resulting conditions under which all market participants will be participating in the market. In Alberta's market and transmission framework, there are no explicit or implicit transmission rights. While an area may be unconstrained at the time a new market participant connects, conditions may change and new transmission system constraints on the system may arise. In such cases, these Practices and sections of the ISO rules related to transmission constraint management govern all market participants access to the transmission system and electricity market. 1 EUA s. 17(g) and s. 28 2 EUA s. 16. See also s. 28(2) of the Treg which requires the AESO to make reasonable efforts to ensure that the interconnection of a generating unit to the transmission system is undertaken in a timely manner 3 EUA s. 33 4 EUA s. 16, s. 17(b) and s. 29 5 EUA s. 34, TReg s. 17 6 EUA s. 17(i) 7 EUA s. 17(h) 8 EUA s. 17(b) Page 3
The current market and transmission framework relies on an uncongested transmission system, particularly under normal operating conditions 9. System studies may determine that a system access service request will result in constraints in an area. While the AESO plans the transmission system to accommodate all system access service requests, the AESO makes decisions related to the timing and specific conditions for connections in constrained areas. To that end, the AESO has considered, as part of this document, constraints under different system operating conditions related to requests for system access service, and the application of these Practices to the same. In applying the Practices, the AESO notes that all constraints that arise in real-time are treated in the same manner under section 302.1 of the ISO rules, Real Time Transmission Constraint Management, no matter what the cause of the constraint or if a remedial action scheme has been activated. 3 Practices for System Access Service 3.1 Conditions for System Access Service The following three (3) conditions must all be met before a market participant will be connected in a constrained area: 1. Where the AESO has determined that a single contingency event will result in a constraint that requires a connection remedial action scheme or that the constraint arises under normal operating conditions 10, the AESO must make publicly available a plan to remove the constraint 11. The Alberta reliability standards obligate the AESO to plan a system that avoids single contingency event constraints 12. 2. The AESO must have determined that new and existing market participants that are connected and that are affected by a constraint have the ability to utilize energy market offers and bids which can reasonably be used to determine competitive access to the market through the transmission system or have the operational flexibility to comply with directives. 3. The AESO must have determined that it will be able to operate the system in a safe, reliable and practical manner after the connection of the new market participant. The AESO is of the view that the first condition above is required to provide reasonable system access to existing connected market participants. Given the AESO s legislated duties, the AESO has determined that when it imposes system access service restrictions, such as a connection remedial action scheme for single contingency events, the AESO must also provide a plan to remove those restrictions in a timely manner. Such plans are made public before or at the same time as the AESO s submission of the connection need identification document to the Alberta Utilities Commission ( Commission ). The public documentation of a plan to remove a connection-related constraint may take several forms. The AESO currently provides information on transmission facility projects the AESO proposes to initiate, or has proposed, in: the AESO Long-term Transmission Plan, the AESO Long-term Transmission Plan Progress Report, and need identification documents 9 TReg s. 15(1)(e)(i) and (f) 10 Note that a publicly available plan is not required where constraints arise under abnormal conditions and the AESO can manage the constraint using procedures in real time, and where constraints arise under abnormal operating conditions that involve multiple contingencies where a connection remedial action scheme is required. 11 EUA s. 34(1), Transmission Regulation s 11 12 TPL-002-AB-0 System Performance Following Loss of a Single BES Element Page 4
All of these documents are public and specify the transmission facilities that are proposed to be built and the planned in-service date for those facilities. The AESO must ensure that the transmission facilities proposed in these documents are sufficient to remove any identified connection-related constraints. When the AESO determines that constraints will arise under normal operating conditions after a connection, the AESO may determine it is appropriate to file an exception, for approval by the Commission, under section 15(2) of the Transmission Regulation. In these circumstances, the AESO may document the plan to remove the constraint within an exception study, which will be filed with the Commission at the same time as the AESO s connection need identification document is submitted. The exception study will identify constraints, the transmission facilities that are needed to remove the constraints, and provide an estimate of the in-service date for those facilities. The AESO may also determine that a broader local area study is needed when there are several new connections proceeding in the same general time frame in an area. In these circumstances, the AESO will document the transmission development related to the group of connections within the local area capability study. The local area capability study examines the AESO s ability to provide system access under market dispatch conditions when certain abnormal operating conditions exist on the transmission system. The local area capability study identifies the constraints that arise and sets out an acceptable transmission facility solution with a proposed in-service date for that solution. The local area capability study results will be made publicly available and referenced in one or more of the need identification document filings related to the study. Exception studies and local area capability studies are documents used only to provide sufficient information to market participants to allow a system access service request to temporarily proceed through the connection process. When these studies are referenced as part of an AESO connection need identification document submission, then, in advance of energizing the connection, the AESO will identify the transmission facility enhancements required to remove the constraint in a Long-term Transmission Plan or a Long-term Transmission Plan Progress Report or a related system need identification document submitted to the Commission. 3.2 Rationale for Conditions for System Access Service The AESO provides the following commentary on the conditions set out above to aid market participants in understanding the high level rationale used by the AESO in developing these Practices. The rationale for the first condition is that it: (a) provides new investors with greater certainty around the approval process related to system access service requests; (b) grants investors and all market participants the ability to consider the potential curtailment risks related to future connections beyond their own project(s); and (c) gives existing market participants clarity regarding the impacts of new connections and the alignment of the AESO processes with the Transmission Regulation 13 requirements. The rationale for the second condition is that it: (a) ensures market participants have the ability to compete in the market; (b) provides exceptions for load based upon operational flexibility; and 13 TReg s 15 Page 5
(c) supports the efficient use of the transmission system and the timely provision of system access service. The second condition encourages new generation investment and avoids unreasonable market participant curtailment. The AESO is of the view that if a market participant s energy market offers or bids can be reasonably used to determine competitive system access, then it is also reasonable to allow a related connection to proceed even when constraints arise. If market participants offers represent their willingness to participate in the electricity market when there are no constraints, then it follows that it is also reasonable to use those same offers as a basis to curtail during a constraint. Load market participants, in particular, may not be able to bid or may not have the operational flexibility to significantly vary consumption to provide a competitive response to system changes. In those situations where market participants are restricted from providing offers or bids due to the nature of the constraint, or where the market participant does not have operational flexibility, the AESO will advise the market participant of the timing of planned transmission facilities, giving the market participant the opportunity to align their development plans with the planned transmission capability of the transmission system. The rationale for the third condition is that it: (a) outlines a practical approach which recognizes operational limitations; (b) enables the AESO to deal with complex transmission system issues that may arise over time; and (c) provides for safe, reliable and economic operation of the interconnected electric system to the benefit of both new and existing market participants in an area. The third condition reflects the AESO s legislated duties with regard to the safe, reliable and economic operation of the system, which includes a consideration of practicality of operation. When deciding whether a connection should proceed, the AESO is obligated to consider the impact of the connection on its ability to operate the system given existing constraints and potential other new constraints in the area or on the transmission system generally. An important consideration is the ability of a new market participant facility to comply with directives and, in particular, the ability to curtail. 14 When new connections impact the AESO s ability to operate the system in a safe, reliable and practical manner, the AESO provides a plan which aligns with the availability of transmission system enhancements or provides other solutions, where possible, that alleviate the concern. The affected market participant may consider staging the proposed connection in a way that utilizes the existing and planned transmission capacity. 4 Application of the Practices for System Access Service The AESO applies the Practices to all system access service requests. The AESO individually assesses each system access service request and develops a specific and appropriate connection proposal. System access service requests may lead to the AESO s determination that constraints will arise under one or more operating conditions, including (i) under normal operating conditions, (ii) under abnormal operating conditions and (iii) under operating conditions where a connection remedial action scheme is required. The application of the Practices to each of these operating conditions is discussed in the sections below. It is important to note that there are operating conditions where condition one of the Practices is not relevant. Specifically, condition one does not need to be met when constraints are anticipated to arise: under abnormal operating conditions and the AESO can manage the constraint using procedures in real time, and under abnormal operating conditions that involve multiple contingencies where a connection remedial action scheme is required 14 ISO Rules Section 301.2: ISO Directives Page 6
For clarity, conditions two and three of the Practices must be met in all circumstances where constraints are anticipated to arise. 4.1 Constraints Managed Under Abnormal Operating Conditions System studies related to a system access service request may indicate that constraints will exist under abnormal operating conditions. If the AESO can manage such constraints by following procedures aligned with the constraint management sections of the ISO rules and market participants energy market offers and bids can be reasonably used to determine competitive system access, the AESO allows the connection to proceed through the AESO Connection Process once it has determined that conditions 2 and 3 of the Practices are met. A plan under condition 1 of the Practices to relieve the constraint may not be required if the AESO expects the threshold set out in section 15 of the Transmission Regulation will be met. The AESO notifies affected market participants of the impact of the constraint as part of the Connection Process. 4.2 Constraints Managed by a Connection Remedial Action Scheme Connection remedial action schemes ensure the reliability of the transmission system under abnormal operating conditions where one or more transmission facilities are out of service and provides for effective and efficient use of the transmission system on a temporary basis until transmission facility enhancements can occur. System studies related to a system access request may indicate that constraints will exist under abnormal operating conditions and the constraint may be such that the system is not adequately protected through system controller action alone until system enhancements are in place. If the AESO can manage system reliability with the use of a connection remedial action scheme(s) and a plan to remove the constraint has been identified and made publicly available, then the AESO gives the market participant the option to connect using a temporary connection remedial action scheme while the permanent wires solutions are being built. The connection remedial action scheme automatically curtails system access when abnormal operating conditions occur. The connecting market participant can choose to accept connection with a temporary connection remedial action scheme or stage the proposed connection development in a way that utilizes the existing transmission capacity or align the project in-service date with the AESO planned transmission enhancements. The connection remedial action scheme is assigned to the connecting market participant only and is not shared with existing connected market participants who may also be effective in managing the constraint. The AESO is of the view that this is a necessary approach which is practical, fair and equitable for all market participants and is consistent with the AESO s legislative obligations 15. When a connection remedial action scheme is a reasonable alternative, the AESO will assign a temporary connection remedial action scheme to the last load or generator connecting to the system in a congested area. This is a practical solution to a temporary constraint condition, and allows the market participant some access to compete. The order of connection is determined by the AESO s connection queue management process in effect at the time. The pro rata assignment of a connection remedial action scheme to multiple generating units that are effective in relieving the constraint is not practical and will not be used. As mentioned above, the AESO will assign the connection remedial action scheme to the new generation market participant, who has the 15 Including the obligation as s. 18(1) of the EUA to operate the power pool in a manner that is fair, efficient and open to all market participants exchanging or wishing to exchange electric energy through the power pool and that gives all market participants a reasonable opportunity to do so. Page 7
option to accept the limited system access service conditions, stage the project development, or align the project timeline to when the required facilities are in place. Connection remedial action scheme assignment and the order of connection remedial action scheme activation in a constrained area is determined by the market participant project status in the connection queue that is maintained as part of the AESO Connection Process. For practical reasons, connection remedial action schemes are assigned and utilized on a last on first off basis using the project s relative position in the connection queue in the constrained area. Once the connection remedial action scheme is activated and the system stabilizes, then the normal constraints management protocol is utilized. The curtailment caused by the connection remedial action scheme is only temporary until normal procedures can be employed. If the AESO cannot practically operate the system in this manner, the use of a connection remedial action scheme solution may not be an acceptable solution for the AESO and the connecting market participant must either choose to stage the proposed connection development in a way that utilizes the existing transmission capacity or they must align the project in-service date with the AESO planned transmission enhancements. If a temporary single contingency connection remedial action scheme is required for a connection, the AESO may require the connection remedial action scheme to also have the functionality to manage low probability multiple contingency events on a permanent basis. These Practices provide for increased system access service in post-contingency situations and is permitted provided the AESO continues to meet its obligations under section 15 of the Transmission Regulation. Therefore, condition one of the Practices does not need to be met when constraints are anticipated to arise due to multiple contingencies and a connection remedial action scheme is required. 4.3 Constraints Under Normal Operating Conditions Constraints that are anticipated to arise under normal operating conditions are contemplated in regulation 16 and government policy but are only authorized in specific and limited circumstances when such exceptions are filed with the Commission for approval 17. Normal operating conditions occur when all transmission facilities in an area are in service and the system can be reliably operated without system controller action should any single transmission facility become unavailable. When it is determined that constraints are anticipated to arise under normal operating conditions, the AESO connects market participants and facilitates competition for system access for all market participants. From a system access service point of view, proceeding to connect market participants under normal operating conditions does not create transmission rights, explicit or implicit, for existing market participants and is aligned with government policy. The transmission system is also being used more efficiently and system access service is provided on a timelier basis when connections are advanced in this manner. 16 TReg s.15(1)(e)(i) 17 TReg s.15(2) Page 8