Implementing Carbon Budgets in New and Existing Buildings

Over the last two decades, the building industry has been developing new ways of decreasing energy use and related carbon emissions in new buildings – be it through the use of a range of rating systems or improved building codes such as BC’s Step Code – but programs and policies to drive reductions in the existing building stock have proved more challenging.   

In early 2022, the City of Montreal rolled out a new requirement for large, existing buildings to measure and disclose their fossil fuel usage on an annual basis. Tracking and disclosing energy usage will be followed by mandatory reduction targets. This comes on the heels of legislation implemented by the Province of Quebec that will prohibit new oil-based heating systems and limit new natural gas systems, beginning in 2024. These are bold moves, and so watching how these policies roll out in Montreal will be helpful for informing similar policies across the country. 

I recently spoke with Philippe Dunsky, President of Dunsky Energy + Climate Advisors as part of SvN Architects & Planners LinkedIn Live Series – SvN Speaks. Based in Montreal, Dunsky brings over 30 years of experience supporting governments, utility companies, businesses, and non-profits across North America to accelerate the transition to clean energy through policies, strategies and investment decisions.  

Dunsky’s firm played a key role in Montreal’s climate bylaws, first by mapping Montreal’s Greenhouse Gas (GHG) footprint, and then assessing reduction opportunities and costs. This initial work found that the Greater Montreal Area has the potential to realistically achieve 55-60% GHG reductions by 2030 and – 100% — or “net zero” emissions — by 2050. The City of Montreal adopted those targets, and proceeded to develop a plan, with Dunsky’s support, to achieve them.   

The plan’s focus on emissions from buildings is noteworthy. At a high level, owners must measure and disclose their buildings’ emissions to the City by 2024, a reasonably simple requirement because measuring the fossil fuels required to heat buildings doesn’t include measuring embodied carbon. The disclosure process begins with buildings over 15,000 sq. m., followed by buildings above 5,000 sq. m. and 2,000 sq. m. in 2025 and 2026, respectively. After this initial “information” period, mandatory GHG performance requirements take effect, starting in 2028, when the largest buildings have to satisfy the first level of mandatory emissions reductions.  

As Dunsky noted, “What’s critical is that the emissions caps are going to be laid out in advance so that everyone knows where they need to be at each milestone leading up to 2040, when every building will have to be at net zero.”