- Alectra Utilities Corp.
- Algoma Power Inc.
- Atikokan Hydro Inc.
- Bluewater Power Distribution Corp.
- Burlington Hydro Inc.
- Canadian Niagara Power Inc.
- Centre Wellington Hydro Ltd.
- Chapleau Public Utilities Corp.
- Cornwall Street Railway Light & Power Co.
- Elexicon Energy Inc.
- E.L.K. Energy Inc.
- Entegrus Powerlines Inc.
- EnWin Utilities Ltd.
- Enova Power Corp.
- EPCOR Electricity Distribution Ontario Inc.
- ERTH Powerlines Corp.
- Essex Powerlines Corp.
- Festival Hydro Inc.
- Fort Frances Power Corporation
- GrandBridge Energy Inc.
- Greater Sudbury Utilities Inc.
- Grimsby Power Inc.
- Halton Hills Hydro Inc.
- Hearst Power Dist. Company Ltd.
- Hydro Hawkesbury Inc.
- Hydro One Networks Inc.
- Hydro Ottawa Ltd.
- InnPower Corp.
- Kingston Hydro Corp.
- Lakefront Utilities Inc.
- Lakeland Power Distribution Ltd.
- Milton Hydro Distribution Inc.
- Newmarket-Tay Power Distribution Ltd.
- Niagara Peninsula Energy Inc.
- Niagara-On-The-Lake Hydro Inc.
- North Bay Hydro Distribution Ltd.
- Northern Ontario Wires Inc.
- Oakville Hydro Electricity Distribution Inc.
- Orangeville Hydro Ltd.
- Oshawa PUC Networks Inc.
- Ottawa River Power Corp.
- PUC Distribution Inc.
- Renfrew Hydro Inc.
- Sioux Lookout Hydro Inc.
- Synergy North Corp.
- Tillsonburg Hydro Inc.
- Toronto Hydro Electric Systems Ltd.
- Wasaga Distribution Inc.
- Welland Hydro Electric System Corp.
- Wellington North Power Inc.
- Westario Power Inc.