New Transmission Recommendations to Enable Growth Across Ontario
August 21, 2026
As electricity demand continues to grow and new supply resources connect to the grid across Ontario, bulk transmission planning plays a critical role in supporting long-term growth, enabling new and expanding industries and ensuring the province remains competitive in an increasingly electrified economy.
In response to rising demand and evolving reliability needs, the IESO has developed three bulk transmission plans that outline recommendations for a phased approach to new and reinforced transmission infrastructure. The plans identify prudent investments needed in the near term while preserving flexibility to advance additional projects as demand materializes, ensuring infrastructure is developed when it is needed and supported by system requirements.
North of Sudbury Bulk Plan
In the area north of Sudbury, increasing demand from industrial and mining projects, electrification initiatives, and potential future resource development triggered an assessment of the bulk transmission system. The IESO evaluated transmission needs across the northern network, balancing broader system requirements with regional constraints and interface limitations while facilitating the timely connection of new demand to support growth and economic development. For more information please visit:
North of Sudbury Bulk Plan Backgrounder
South and Central Bulk Plan
The IESO initiated bulk transmission planning for the southern and central regions of Ontario to identify near-term actions and longer-term options to ensure the transmission system can meet forecast demand growth. The IESO also evaluated the grid’s ability to enable the connection of potential future generation resources — including new nuclear — and to reliably supply emerging demand across the Greater Toronto Area and Windsor–Hamilton corridor. As a result, the IESO is recommending a series of investments that will strengthen system resilience and improve reliability — allowing more electricity to flow across the high-voltage grid. To learn more please click:
South and Central Bulk Plan Backgrounder
Eastern Ontario Bulk Plan
With accelerating electricity demand driven by electrification and industrial development, the IESO initiated the Eastern Ontario Bulk Plan to identify near-term actions and longer-term options and ensure the transmission system can reliably support forecasted growth. The recommended transmission upgrades increase the overall transfer capability in eastern Ontario to reliably meet growing needs while creating additional optionality for expanded interties and future exports. For more details please visit: