Author/Contributor: Builders for Climate Action, NRCAN
Alberta Context:
Although Alberta was not specifically mentioned in the report, many of the findings and information were applicable to Alberta. For example, the report mentioned Prince Albert, Saskatchewan, which is in climate zone 7A (the same as Edmonton and Calgary). Given that Saskatchewan’s grid intensity was similar to Alberta’s, the report’s analysis regarding Operational Carbon Emissions (OCE) and the relationship between energy efficiency and fuel source was relevant to Alberta. The report’s conclusions on the influence of Material Carbon Emissions (MCE), energy efficiency, and the viability of low-carbon materials were relevant in Alberta and across Canada.
Summary:
The study by Builders for Climate Action shows that Material Carbon Emissions (MCE) are a major, and often overlooked, contributor to the climate impact of Canadian housing. The findings make it clear that Canada can’t meet its 2050 net-zero targets without reducing Material Carbon Emissions.
Some key findings from the report:
- Material Carbon Emissions are a huge and major source of emissions. Newly constructed low-rise homes in Canada generate an estimated 14.1 Mt CO₂e annually (equal to the emissions of 3.1 million vehicles) – pg. 4 (Achieving Real Net-Zero Emission Home Report).
- Material choice can have the largest impact. “A Canadian home can have a high Material Carbon Intensity of 758 kg CO2e/m2 or a low of -84 kg CO2e/m2 (representing net carbon storage, rather than emissions). The very wide range of results indicates that material selection can impact the total emissions of a new home by as much as 842 kg CO2e/m2 without changing the design or performance of the home.” – pg. 2 (Achieving Real Net-Zero Emission Home Report)
- Energy efficiency can unintentionally increase emissions. Moving up a tier in the National Building Code (NBC) often requires more insulation, and when high-carbon materials are used, this increases MCE (sometimes outweighing operational energy savings).
- Net zero Material Carbon Emissions are achievable today. Using widely available (and code-compliant) products, builders can reach net-zero or even net-negative MCE. With carbon storing materials such as cellulose, wood fibre, straw bale, or hempcrete, homes can act as carbon sinks.
- Reducing the material carbon footprint (MCE) doesn’t necessarily increase project costs. In fact, many low-carbon materials (such as cellulose) are inexpensive, while some high-carbon options (such as brick and XPS) are costly. Therefore, builders can significantly reduce MCE without raising their project budgets.
- The report recommends introducing a combined metric – Carbon Use Intensity (CUI). This metric combines Material Carbon Emissions and Operational Carbon Emissions over a set timeframe. CUI would provide a measure of total climate impact, prevent trade-offs that increase MCE, and allow regions to tailor compliance strategies to their needs. In cleaner-grid regions, reducing MCE yields the largest benefits. In carbon-intensive regions (such as Alberta and Saskatchewan), improving operational performance remains essential.
This study shows that choosing materials is a powerful and important choice for the climate and is essential to achieving net-zero buildings in Canada. Read the full report here.
