2025 Edition
TAF has published Ontario emissions factors since 2017 to support best practices in carbon quantification. Accurate emissions factors reveal how various interventions impact carbon reductions.
Planning for decarbonization and electrification is becoming more complex as more natural gas is used to generate electricity in Ontario. These numbers and guidelines allow practitioners to quantify carbon emissions and plan climate strategies as accurately as possible. We update the factors annually with available data, developed in consultation with other experts and stakeholders.
Get to know the updated factors and guidelines.
Regulatory Recommendations
To address data gaps and growing emissions from the electricity grid, TAF recommends the following:
- That the IESO publish historical marginal resource data and future projections to enable better understanding of the carbon impacts of load shifting.
- That the Ontario Ministry of Energy and Electrification direct the IESO to accelerate the procurement and development of new non-emitting generation.
Decision Aids
The following table can assist in determining which specific emissions factors should be used in common scenarios. The factors presented in this guideline account only for direct (combustion) emissions and thus can underestimate the global impact of interventions.
Annual AEF
- Historical or forecasted inventory analysis.
Hourly AEF
-
Historical inventory analysis, specifically where more precision is needed.
1- Evaluating long-term changes in demand
Annual AEF (Proxy for annual long-run MEF)
- Historical or forecasted analysis.
- For the majority of scenarios, including fuel switching, energy efficiency, and compliance with standards and/or building portfolio targets.
2- Evaluating short-term changes in demand
Annual MEF and Monthly/Seasonal MEF
- Historical or Forecasted analysis.
- For specific use cases like load shifting (e.g., smart appliances, smart heating systems, electric vehicle charging), and energy/ battery storage.
3- Evaluating short-term changes in demand
Combination of Annual MEF and Annual AEF (Proxy for annual long-run MEF)
- Historical or Forecasted analysis.
- For projects involving new electricity generation, such as solar installations