Home Energy Retrofit Priorities in Edmonton with a Decarbonizing Electricity Grid
Creators: Lartey, Elizabeth
Publisher: name: University of Alberta Library
Year: 2024

<p>In 2021, the City of Edmonton (CoE) released an Energy Transition Strategy and Action Plan (ETSAP) outlining how Edmonton can achieve ``net zero&quot; greenhouse gas (GHG) emissions by 2050. The plan indicated that 83\% of GHG emissions could be reduced between 2020 and 2050 through energy savings and emission reductions from fossil fuel combustion with the remaining 17% offset through carbon capture and sequestration along with nature based solutions. The ETSAP aligned with the Paris Agreement of limiting the overall global temperature from pre-industrial levels to 1.5C and Canada&#39;s goal of net zero by 2050. Historically, Alberta&#39;s electricity system has been GHG intensive however, Alberta is in the process of phasing out its coal fleet. Forecasts for Alberta&#39;s electricity grid anticipate a significant decrease in electricity emissions than previously modeled, potentially affecting the strategy outlined in the ETSAP. </p>

<p>This analysis examined how Alberta&#39;s decarbonizing electricity grid could affect the priorities and outcomes for the CoE&#39;s goal of achieving net zero by 2050 as it pertains to single family homes (SFHs) between 2024 and 2050. Edmonton&#39;s residential sector accounted for 18\% of GHG emissions in 2020 and the ETSAP focuses on reducing GHG emissions by a combination of rooftop solar PV systems, heat pumps, electric water heaters, building envelope, and lighting retrofits. To compare how this strategy is affected by the changes in the electricity system, a representative pre-2017 SFH in Edmonton was modeled using HOT2000 before and after installing a combination of the retrofits mentioned above. A diffusion of innovation (DOI) method was used to estimate the adoption of the various retrofits between 2024 and 2050. The analysis compared the GHG emissions and energy cost savings using forecasts from the Environment and Climate Change Canada (ECCC) in 2023 as well as a 2022 model from the Alberta Electricity System Operator (AESO), and compared the results to the ECCC 2021 forecast which was the forecast at the time the ETSAP was released. </p>

<p>Previously, the focus was on reducing electricity consumption to reduce GHG emissions however, more recent electricity forecasts showed that GHG reductions were 29-50% higher when installing electric water heaters and/or heat pumps using the 2022-2023 forecasts. This result indicates that reducing electricity consumption could no longer be a focus with lower emission factors. Homes could increase electricity consumption when natural gas consumption is reduced and see GHG reductions. Combining solar PV with heat pumps and electric water heaters resulted in the highest GHG reduction using all considered electricity emission factor forecast. However, when comparing the GHG reductions between the electricity emission factor forecasts, GHG reductions are 3-12% less on the 2022-2023 forecasts. The CoE would need to increase the target of homes completing retrofits by 4-14% or homes would need to further reduce natural gas consumption by 2-45%. </p>

<p>Lastly, the cost analysis included a low and high energy cost scenarios with and without the federal carbon tax in place, to determine the financial viability of each retrofit combination. Homeowners are more likely to recoup project costs before the end of the solar PV system useful lifetime within the high energy cost scenario with solar PV exports and the carbon tax. If the CoE intends to meet the targets within the ETSAP as electricity emissions decrease, the priority should be on targeting more homes to install electric space and water heating systems with solar PV to reduce the most GHG emissions and solar PV exports assisting with reducing project costs.</p>