NEM Partner Profiles: IESO

Leading up to National Engineering Month Ontario 2023 events we are profiling our partners and the contributions they make to Ontario’s engineering community. This post features the Independent Electricity System Operator (IESO).

The Independent Electricity System Operator (IESO) works at the heart of Ontario’s power system to deliver key services across the electricity sector. These include managing the power system in real-time, planning for the province’s future energy needs, enabling conservation, and designing a more efficient electricity marketplace to support sector evolution.

We are a purpose-driven organization committed to ensuring Ontario electricity users enjoy a reliable, affordable, and sustainable supply of energy. Professional engineers play an important role in helping us deliver on our mandate and do mission-critical work in areas such as transmission planning, real-time operations, system integration, compliance and enforcement, and more.

In this exciting time of energy transition and electrification, the IESO is leading many initiatives, one of which is providing direction, expertise, and leadership to support the province’s shift away from fossil fuels to a more sustainable energy future. With one of the cleanest energy supply mixes in North America, Ontario has an advantage that will help drive broad emission reductions as other sectors of the economy decarbonize. The IESO has explored many elements involved in achieving Ontario’s decarbonization goals and published them in the Pathways to Decarbonization report. Some of the key findings from this report include:

  • By 2035, the system could be less reliant on the natural gas fleet, lowering emissions by 60 percent below the IESO‚Äôs original forecasts, provided sufficient non-emitting supply is in place when needed to meet electricity demand;
  • Attaining a decarbonized electricity sector by 2050, alongside aggressive electrification, would require a system more than double the size it is today at an estimated cost of around $400 billion;
  • Significant investments in capital, materials, and labour will be required, and emerging technologies will need to be developed;

Planning is essential to a reliable, sustainable electricity system. The IESO prepares for the future, whether it be through forecasting Ontario’s demand for electricity from near real-time to 20 years out, or by working with sector stakeholders to develop approaches to address reliability needs in a timely, cost-effective, and flexible manner. The IESO’s Annual Planning Outlook (APO) forecasts electricity demand, assesses the reliability of the electricity system, identifies capacity and energy needs, and explores the province’s ability to meet them. This outlook helps to inform decisions that will lay the foundation for a reliable and affordable electricity future. Some key findings include:

  • Ontario‚Äôs supply mix will undergo significant change over the next two decades;
  • Energy requirements for new resources continue to emerge around 2029 ‚Äď existing resources will need to operate differently than today to meet increased capacity and energy requirements;
  • Multiple factors are expected to impact the daily demand profile over the next 20 years, including year-round battery electric vehicle charging, increased electric space heating, the connection of more industrial facilities to the grid, and increased agricultural greenhouse consumption.

In the coming years, we will continue to see an unprecedented transformation of Ontario’s power grid. Our reliance on electricity will increase, driven by economic growth, decarbonization, and consumer preferences. As the province’s system planner, the IESO is taking action today to prepare for our near- and long-term energy needs.

The IESO is expanding our capacity to manage a larger and more complex power system. In this exciting time of energy transition, we are seeking a variety of skills and experience to join our team. The IESO has been awarded the 2023 Greater Toronto’s Top Employer award for our benefits, employee wellness, and professional development opportunities. Please visit to explore some of our current vacancies.

To learn more about the IESO‚Äôs role in Operating Ontario‚Äôs Power System Today and Tomorrow, we will be hosting a virtual event on Thursday, March 9th, 10-11 am. We encourage you to join us ‚Äď Ontario‚Äôs energy future is bright.

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