Operating Reserves
Operating reserves are used by the AESO to maintain system reliability and to ensure power is available when we need it. Because electricity can not be stored (and saved for when it is required), power supplied must always be equal to power being consumed. To achieve this balance our system controllers constantly monitor the demand in the province and match it with available supply. Operating reserve is used by the system controller to ensure that this supply-demand balance is achieved seamlessly.
In Alberta, operating reserves are categorized as regulating reserves, spinning reserves and supplemental reserves, where each type of reserve performs a unique function.
Due to the size and complexity of the AIES, the balance between generation (supply) and consumption (demand) is not instantaneous – often there is a lag while generation is catching up to supply or while generation is decreasing in response to lower demand. Regulating reserves instantaneously provide the power difference between supply and demand required during that lag period.
Spinning and supplemental reserves (collectively referred to as contingency reserves) are used to maintain the balance of supply and demand when an unexpected system event occurs. These reserves provide capacity the system controller can call on with short notice to correct any imbalance. These reserves can come from the supply side (generators) or from the demand side (load curtailment by turning off large electrical consumers to reduce demand immediately – note load can only provide supplemental reserve). Spinning reserves are the fastest acting contingency reserve. Generators providing spinning reserves are synchronized to the grid (the turbine is “spinning” but not generating power), this unique feature allows the reserve to be provided very quickly. In addition to the ability to respond very quickly, spinning reserves also provide frequency support to the AIES. Supplemental reserves on the other hand are not required to be synchronized to the grid and are slower to respond when called upon.
The amount of operating reserve the AESO procures is determined by reliability standards set by the Western Electricity Coordinating Council (WECC) of which the AESO is a member.
Everyday the AESO procures operating reserves from generators and loads through an on-line exchange called Watt-Ex. Prices for operating reserves are determined on a daily basis through this competitive market.
The AESO procures both active and standby operating reserve. The purpose of active reserves is to meet the requirements of the AIES under normal operating conditions. Assets in this portfolio will normally be dispatched. The purpose of standby reserves is to provide additional reserves for use when the resources available under the active portfolio are insufficient. Generally, before any resources will be dispatched from the standby portfolio, all resources have been dispatched from the active portfolio.
Operating Reserve Resources
Technical Requirements for OR Market Participants
These documents provides the technical requirements for participation in the operating reserve market.
Operating Practices & Procedures (OPPs) for Operating Reserves
The following OPPs make reference to operating reserves – 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 401: Regulating Reserve Service
This OPP defines the policy and procedures for the System Controller in dispatching generators for regulating reserve service to manage regulation range levels in the Alberta control area.
OPP 402: Supplemental and Spinning Reserve Service
This OPP defines the contingency reserve criteria for the Alberta Interconnected Electrical System (AIES) and provide guidelines and procedures for the System Controller in dispatching assets for supplemental and spinning reserves and in issuing an ancillary service directive for the delivery of supplemental and spinning reserve energy.
OPP 403: External Spinning & Supplemental Reserves from B.C.
This OPP defines the guidelines for participants and the System Controller, and the procedures for the SC, in using external spinning reserve and external supplemental reserve from BC.
OPP 404: Ancillary Service Dispatches and Directives
This OPP provides policies for the System Controller and participants, and procedures for the System Controller, in the exchange of ancillary service dispatch and directive messages and responses.
OPP 406: Firm Load Responsibility
This OPP outlines the process and calculations to be used by the ISO for determining firm load responsibility (FLR) used in the contingency reserve calculations.
Reliability Standards
View Alberta’s reliability standards.
Operating Reserve Statistics
Access various reports on the operating reserve market including stand-by activations, daily OTC transactions, regulating reserve range, and reserve volume forecasts
Operating Reserve Market Re-design
These documents provide information on the proposed operating reserve market re-design. Documents include discussion papers, recommendation papers, stakeholder presentations and stakeholder feedback, as well as additional information relating to the topic.
Alberta Watt Exchange Limited (Watt-Ex)
Official website of Watt-Ex (The on-line electronic exchange for the procurement of operating reserves).
Western Electricity Coordinating Council (WECC)
Official website off WECC
Market Surveillance Administrator (MSA)
Official website of MSA