Electricity Grid Emissions

In 2024, electricity emissions in the GTHA increased by 28%.

GTHA electricity emissions are influenced by two primary factors: overall electricity demand in the region and the carbon intensity of the provincial grid used to meet that demand. 

In 2024, total electricity demand in the GTHA region increased by 2.4%, from 58.8 to 60.3 terawatt hours. If the carbon intensity of the electricity grid had remained the same as in 2023, then electricity emissions would have risen by just 2.4%. However, the carbon intensity of the grid increased 25% in 2024, reaching 73.8 gCO₂eq/kWh.

This has led to an overall 28% increase in electricity emissions.

This is a direct consequence of the province’s increasing reliance on gas-fired electricity generation, which is forecast to continue to increase over the next 10 years, undermining electrification and carbon reduction efforts in other sectors.

Forecasted Ontario electricity grid emissions were estimated using the IESO's 2025 Annual Planning Outlook (APO) energy adequacy forecast scenario. This scenario is derived from Capacity Expansion model simulations, which identify the least-cost supply mix required to meet Ontario’s provincial resource adequacy needs. It represents an illustrative resource mix, one potential pathway for meeting future electricity demand, rather than actual procurement outcomes.

Across the GTHA, electricity emissions have more than doubled since 2020. And if they continue to increase at the current rate, they will again double well before 2030. While the IESO projects that provincial electricity emissions will start to decline in the long term, there is considerable uncertainty in this forecast, especially when predicting how much new gas capacity versus non-emitting supply will be procured.

To address the problem of rapidly rising electricity emissions, it is imperative to prohibit any new or expanded gas-fired electricity generation capacity and limit how often our existing gas plants are operated. Additionally, it is critical to scale energy efficiency and conservation efforts to reduce energy waste, scale up load flexibility to increase utilization of existing grid infrastructure, and invest in new local and utility-scale clean generation, including distributed solar and storage in transmission-constrained urban areas.

Spotlights

• Ontario is making significant investments in expanding its energy efficiency programs over the next twelve years. Over a dozen programs are planned providing financial incentives for homeowners and business targeting:
  • 18,000 GWh of electricity savings (equivalent to London + North Bay + two Ottawa-sized cities).
  • 3,000 MW of peak demand savings by 2036 (equivalent to 70% of City of Toronto's summer peak demand).
• IESO released the 2025-2027 demand-side management plan that is forecasted to achieve 900 MW of peak demand savings and 4.6 TWh of electricity savings by 2027. Program details, budget breakdowns, and expected targets are included in the report.