Marguerite Lake Compressed Air Energy Storage Project Connection (2845)

Cache Power Corp. (Cache Power) has applied to the AESO for transmission system access to its approved Marguerite Lake Compressed Air Energy Storage Project (Facility) in the Bonnyville area. Cache Power’s request can be met by the following solution:

• Add one 240 kilovolt (kV) transmission line to connect the Facility to the existing Marguerite Lake 826S substation in a radial configuration.
• Modify the existing Marguerite Lake 826S substation, including adding one 240 kV circuit breaker.
• Add or modify associated equipment as required for the above transmission developments.

Abbreviated Needs Approval Process: Notice of Consideration

The AESO intends to consider the need for the Marguerite Lake Compressed Air Energy Storage Project Connection for approval under Section 501.3 of the ISO rules, Abbreviated Needs Approval Process, (ANAP Rule) on or after October 1, 2026. If stakeholders have any questions or concerns, please contact the AESO before this date.

The AESO has determined that the Project is eligible for consideration under the ANAP Rule because the following eligibility criteria have been met:

• Project costs are estimated to be $13M and were classified as participant-related in accordance with the ISO tariff. Additionally, in accordance with the ISO tariff, the AESO has determined that the Market Participant is eligible for approximately $1M of local investment.
• the AESO has completed a participant involvement program (PIP) in accordance with the guidelines in Alberta Utilities Commission Rule 007;
• the Project is not anticipated to result in significant environmental effects; and
• No concerns or objections with the need for the Project have been raised. Prior to making its approval decision, the AESO will address additional stakeholder concerns that arise, if any.

Supporting information about this Project is available in the following documents:

• AESO Project Connection Assessment
• Central Cluster Region Detailed Assessment Report
• TFO Cost Estimate
• AESO PIP Summary

Need Overview

• Need for the Marguerite Lake Compressed Air Energy Storage Project Connection [Posted: January 21, 2026]