FAQ

The city of Toronto is growing, with new housing, businesses, electric vehicles, and transit projects across the city increasing its electricity demand significantly. By 2044, Toronto is expected to double its electricity use. Given the pace of growth in the city, it is important that we accelerate the development of new infrastructure to ensure the electricity system can continue to support the city and enable new economic investment.

Toronto’s electricity needs are mainly served by high-voltage transmission lines carrying electricity from across the province as well as Portlands Energy Centre (PEC) which is strategically embedded within the city to power homes and businesses.

As part of the planning process, the IESO has evaluated transmission options and complementary solutions such as energy efficiency, demand response, and local energy generation and storage to bring more electricity into the city core.

The IESO’s draft recommendations involve a suite of solutions including new and upgraded transmission infrastructure across the city, two battery storage projects in western and eastern Toronto, and targeted incremental energy efficiency, demand response, and customer-sited solar and energy storage, to best meet each part of the city’s unique and growing needs.

As part of the draft recommendations, the IESO has also evaluated a new transmission line to bring in power from the east GTA into downtown Toronto. After balancing the merits of the three potential transmission options, the IESO’s preferred option is a new underwater transmission line from Bowmanville TS to Port Lands in downtown Toronto via Lake Ontario, to be in place by 2034.

For more information on the analysis of options and draft recommendations see the presentation posted on September 25.

Ontario’s bulk electricity system comprises transmission lines that crisscross the province, connecting a diversified supply mix including nuclear, gas, hydro, solar, wind and energy storage, to where the electricity is needed.

Similarly, the third transmission line into downtown Toronto could bring power from these various types of supply.

Yes, energy efficiency will be recommended as part of an integrated solution in the Toronto regional plan.

For more than 15 years, the IESO and utility partners have delivered electricity Save on Energy programs (including energy efficiency, demand response and local generation) in Toronto, generating more than 800 MW of peak demand savings (more than the equivalent of London’s entire peak demand).

In the Toronto regional plan, the demand forecasts assume the continued delivery of Save on Energy program savings, with expected summer savings of 847 MW and winter savings of 757 MW by 2045. Additionally, the Toronto plan considers the potential for even more savings over and above current programs informed by the results of the Local Achievable Potential Study (L-APS) Draft Report. Draft findings show an additional opportunity of 219 MW in the summer and 50 MW in the winter. Draft findings are available online and final results will be shared.

While alternative solutions such as energy efficiency will be part of the recommendation, to meet Toronto’s quickly growing needs, the IESO’s analysis has also identified upgrades to existing and new transmission as part of the solution. For all solutions, the IESO carefully considers technical criteria, cost, timing, and community preferences. For more information on the analysis of options and draft recommendations see the presentation posted on September 25.

As part of the regional planning process, offshore wind generation will not be considered to address regional electricity needs as there is a moratorium on off-shore wind in Ontario. The Ministry of Energy and Mines provides policy direction on this matter.

Renewables such as wind and solar can contribute as part of a cost-effective, diversified mix of solutions. Indeed, the IESO provides incentives for solar panels for residents and businesses through its Save on Energy programs.

Large renewable generation, however, as a sole solution cannot meet peak summer and winter electricity needs in Toronto. This is because their ability to generate is dependent on the availability of sunlight and wind which may be limited during peaks (i.e., limited solar during the winter months). It would also require a significant amount of land that is just not available within the densely built city of Toronto.

The IESO and Toronto Hydro have delivered energy efficiency programs in the Toronto region for over 15 years, generating more than 800 MW of peak demand savings, enough to power a city the size of London, Ontario. But there’s so much more we can do. The IESO has expanded its Save on Energy programs including home upgrades, heat pumps, and more energy efficiency incentives for businesses to help Ontarians reduce even more energy use from the grid, manage their energy costs and help businesses remain competitive.

The new 12-year electricity demand side management framework in Ontario demonstrates the province’s long-term commitment to conserving energy as an energy resource.

In addition to transmission solutions that are being further evaluated to meet the needs for Toronto, complementary solutions including battery storage, energy efficiency, and demand response savings are being studied.

While the Toronto IRRP demand forecasts already assume significant quantities of expected peak demand savings, 847 MW of summer savings and 757 MW of winter savings between 2025 and 2045. Draft results of an IESO study show additional 219 MW of potential summer savings and 50 MW of potential winter savings by 2045 on top of the savings that will be achieved through Save on Energy programs. For context, this summer incremental potential is approaching the peak demand of the City of Oshawa (250 MW).

The IESO’s Electricity Demand Side Management Framework is a $10.9 billion, 12-year funding commitment from the Ontario government beginning January 2025. In addition to achieving energy savings, the new framework is designed to promote the use of electricity to improve energy affordability, expand customer choice and reduce emissions in Ontario, while minimizing impacts to the electricity system.

For more information visit Save on Energy.

The IESO will consider how to best pursue the additional savings opportunities identified in the Local Achievable Potential Study beyond the planned Save on Energy program savings. These additional opportunities could be realized through targeted incentives and other approaches. More information will become available on these additional opportunities.

The IESO’s final recommendations report in October will address the city’s needs in the short, medium and long term. New programs, or infrastructure projects will be actioned by the responsible organization - either IESO, Toronto Hydro or the transmitter, to develop more specific project plans to procure it, including for further analysis and public engagement.

In the case of the third supply line, the IESO will continue to work with government for direction on next steps. All transmission projects will be required to comply with federal, provincial and municipal approvals, permits or requirements, including an Environmental Assessment.

Regional planning is completed in regular intervals with updates every five years or sooner. The Technical Working Group meets annually to review demand forecast projections and potentially initiate regional planning earlier if needed.

Future electricity demand is driven by community growth and intensification, housing targets, economic development, and the electrification of buildings and vehicles; and takes into consideration municipal growth plans, community energy plans, and climate action initiatives.

In 2025, the IESO is forecasting electricity demand in York Region could double by summer 2044 and triple by winter 2044 — reaching approximately 3,000 MW of peak demand — a rate that exceeds the provincial demand growth.

The IESO is recommending a series of near-term solutions that include new transmission infrastructure, upgrades to existing assets, and energy efficiency measures that align with local preferences, policies, and priorities to alleviate transmission congestion and improve reliability. By incorporating several non-wire alternatives to support reliability and growing communities, the need for larger infrastructure to meet long-term needs can be deferred and further studied. Over the long term, the IESO will continue to monitor and evaluate system needs and community preferences in collaboration with local utilities to support local priorities and continued growth, which may include new and upgraded transmission lines and transformer stations.

Based on final recommendations, the transmitter will lead the development of a Regional Infrastructure Plan on how wire options can be implemented, or new resources will be procured through the IESO’s competitive process alongside energy efficiency programs and incentives. The IESO will also have annual Technical Working Group meetings with local utilities to monitor how demand is materializing and determine if the next planning cycle should be initiated earlier than its normal five-year cycle.

Feedback from community leaders, businesses and residents is necessary to inform our recommendations.

The IESO holds webinars for anyone interested in learning more and participating in the process. We are here to answer questions and solicit feedback. We also post your feedback and our responses to it.

You can visit ieso.ca to learn more details about the engagement process and subscribe to be notified of future meetings.