Hello friends,
We are embarking on calculations to quantify avoided embodied carbon from converting an old school building into a multifamily project and I wanted to vet our methodology with you.
Our idea is to first establish a benchmark for a new replacement multifamily building based on published studies. We have found a few studies, including one published by Athena that evaluates the embodied carbon in 10 multifamily projects.
We then plan to quantify materials used in the renovation of our project at hand and use OneClick LCA to quantify the associated embodied carbon in those materials.
By subtracting this value from the benchmarked replacement building, we think we can estimate the avoided embodied carbon from repurposing an existing structure.
Does this sound like a reasonable approach? Have you followed a similar approach when calculating avoided carbon for building reuse? Other ideas on approaches?
Other notes:
- We don’t have a portfolio of multifamily buildings that we can model in-house to establish a benchmark, so are looking to whatever we can find
- I don’t believe we need to calculate the existing school building structure given that the alternative would be a new contemporary structure. In addition, the existing base school building is well over 100 years old and has what would be considered a heavy structure by today’s standards. While we have a decent sense of how it was constructed, there are elements such as the foundation details that are unknown.
- Any other LCA benchmarks for multifamily projects that you may have and are willing to share would be appreciated
Thanks in advance, John M
- If the goal of the study is to calculate the avoided emissions of the renovation versus replacement, you have the right idea to use the embodied carbon of the hypothetical new construction alternative as the baseline rather than the embodied carbon of the original building.
- One catch with hypothetical replacements based on benchmark data (Athena studies or CLF benchmarks) is that the scope of the LCA used to develop the benchmark may not align exaclty with your LCA. For example, they may not have included interior partitions or finishes, and you may want to include them in your study. Same goes for scope boundary around life cycle stages. Just something to keep an eye on to make sure you're comparing apples to apples.
- One thing you might miss using this methodology are end-of-life impacts of materials you demolish in the course of the renovation (or with a hypothetical tear down).
Feel free to reach out directly if you'd like to talk more! -Lori