AIES (Alberta Interconnect Electric System ) Event Log Info


The phrase 'Energy Emergency Alerts' is standard terminology defined by the North American Electric Reliability Council (NERC) for communication among coordinating agencies and control centres. It is used throughout the Western Electricity Coordinating Council (WECC), of which the Alberta Electric System Operator (AESO) is a member.

We provide energy alert notices in the Alberta Interconnected Electric System (AIES) Event Log on our Web site.

The AIES Event Log is a real-time report that is maintained by the system controllers in the AESO's System Coordination Centre (SCC).

The procedure describing how and when the AESO uses the alert messages and their definitions is documented in our operating policies and procedures OPP 802.

As part of our role to plan and operate the Alberta Interconnected Electric System reliably, safely and economically, the AESO works with industry to coordinate planned generation maintenance schedules so that we can manage the system requirements.

At the AESO, it's our job to anticipate and plan for demands on the system and we have operating policies and procedures in place to manage contingencies and worst-case scenarios.

The OPPs are available on our Web site at Rules & Procedures / ISO Rules / ISO Operating Policies & Procedures.

Operating Policy and Procedure (OPP) 802 defines four levels of energy emergency alerts.

Energy Emergency Alert 1

 This alert is declared after all available resources in the energy market have been used to meet AIES firm load.
 Sufficient operating reserves are intact - which means we still have about 500 MW in reserves available.
 Energy is imported through the interconnections with BC and Saskatchewan as per schedules.
 At this point we would also ask customers who have Demand Opportunity Service (DOS) contracts to lower their demand on the system. These are generally customers who have flexible operations to respond to changes in their demand or supply quickly.

Energy Emergency Alert 2

 All steps under Alert 1 have been taken.
 Operating reserves are being used to supply energy requirements.
 Power service is maintained for all firm load customers.
 Load management procedures have been implemented, which may include the voluntary load curtailment program (VLCP), voltage reduction and reduction in non-essential loads.
 Customers who are part of the VLCP have agreed to comply with directives to reduce or stop their power consumption during this type of energy shortfall situation.
 A public communication may have been issued to request customers to voluntarily reduce demand.
 Ancillary service directives have been issued to supplemental and spinning reserves to increase energy supply and firm load is now relied upon for reserve.
 Emergency energy has been requested of neighbouring control areas.
 Regulating reserve is maintained.

Energy Emergency Alert 3

 All steps under Alerts 1 and 2 have been taken.
 Some firm load is curtailed, which means that power service to some customers is temporarily interrupted to maintain the minimum required regulating reserve and the integrity of the overall system. After receiving directives from the AESO system controllers, the distribution facility owners decide which customers are to be temporarily without power at this point in the process.

Energy Emergency Alert 0

 Termination of previous energy emergency alerts.
 Energy supply is sufficient to meet AIES load and reserve requirements.