Electricity Transmission Rates Filing Requirements Review

The OEB has released updated Filing Requirements for Electricity Transmission Applications (Chapters 1 and 2), effective for 2027 rate applications and beyond. These changes aim to improve regulatory clarity, reduce administrative burden, and reflect evolving sector needs.

The most significant update is the introduction of a new revenue requirement setting option under Custom IR, specifically designed for transmitters with a declining rate base. (All update documents (including track change versions) are available in the Consultation Documents section on the right-hand side of this page.)

Other key updates include:

• Higher materiality thresholds to account for inflation since 2016. These apply to both the provision of evidence and the establishment of deferral and variance accounts, helping to reduce regulatory burden and focus adjudication on material issues.
• Clarifications regarding application filing deadlines to better coordinate the annual transmission rate-setting process.
• Minor technical and structural updates to align the Filing Requirements with other OEB relevant guidance documents.

The updates were shaped by stakeholder feedback from consultations held in mid-2025.

Fourteen organizations, including transmitters and consumer groups, participated in the consultation process. The OEB thanks all stakeholders for their valuable input, which helped shape the updated Filing Requirements and accompanying guidance.

Rate Framework for Single-Asset Transmitters

A key focus of the update is to provide guidance on the revenue requirement framework for the growing number of single-asset transmitters now operating in Ontario. Specifically, it aims to clarify the expectations for Custom Incentive Rate-setting (Custom IR) applications required to support filings under this approach.

Effective Date and Future Developments

The updated Filing Requirements are proposed to apply to transmission rebasing applications for 2027 rates.

These updates reflect current legislative and OEB policy frameworks, as well as general regulatory practices. The OEB also recognizes that the transmission sector is evolving. Accordingly, future changes such as the introduction of a Transmission Selection Framework by the Independent Electricity System Operator may necessitate further revisions.

The OEB intends to review these Filing Requirements every five years to ensure they remain fit for purpose.