I’m developing the reduction target for scope 3 emissions for our company, and especially in setting a target related to embodied carbon intensity (which is a key item in our plan). However, we have encountered some challenges and I’m trying to work our way through the following questions:
How to choose the format of the embodied carbon intensity baseline - should it be on a project basis or portfolio basis? Our company has developing projects in different areas, so there are pros and cons either way.
If we choose a project-based embodied carbon intensity target, how should we decide on the baseline and comparison stages (e.g., design in tendering stage, schematic design stage, detail design stage, or even construction stage)? For now, we are thinking of comparing the building information in tendering stage with detail design stage, but we are not sure if there is a recent standard or practice addressing this issue, or if CLF has guidance on this matter.
If we choose a portfolio-based target, I understand CLF and RICS have study on embodied carbon benchmarks for different project types. However, the benchmarks are normally shown in a range instead of a specific number. Is it possible to set a specific number for the whole portfolio baseline? Does anyone know if there is are recent studies or discussions on this topic?
Thank you all and I’d be grateful if anyone would have some recommendations or thoughts.
Hi Viki - we at the Port Authority are also thinking our way through baselining embodied carbon and seeing if we can align it with our climate ambitions. I have been looking at the CLF’s low baseline (20th percentile) as a start for embodied carbon for concrete, knowing we’d have excursions for high early strength mixes.
I have seen baselines set by studying a handful of existing projects in a company’s portfolio and arriving at a carbon intensity per SF. I’ve seen this in cases where a dominant building type is considered (all commercial, residential, or offices). If your portfolio is diversified, then I’d suggest getting those average intensities for each use type (similar to how CLF categorizes their benchmarks).
Hi Dorian - thanks for sharing your approach for concrete, we are also thinking similar approach to set material specification for key building materials such as steel, rebar and concrete. That’s a very good suggestion and really appreciate it!
Hi Andres - many thanks for the suggestion for baseline! LETI also has a similar benchmark with different bands for dominant building types. Please see embodied carbon target for more information. I just wonder if we use the average carbon intensities as baseline, given our building design (like building geometry and mixture of material) is different and our own data is not as comprehensive as CLF or LETI’s database, could those figures be representative? Thanks.
That’s a very good point. A concern of mine is whether all these benchmark studies included consistent material categories as part of the scope. For instance, it could be the case that some of the projects included excluded certain categories, such as finishes or building systems. That adds a layer of complexity to the data which makes it hard to compare
I really like @andres 's suggestion to perform a whole building or embodied carbon LCA on a few typical existing assets your company owns.
This will give you a true baseline for your actual building portfolio. As Andre’s mentioned, all the benchmarks out there include different scope boundaries, so you may end up comparing apples to oranges by accident.
LMN is using this format to compare projects for our internal EC db and assess where we are and where we are going. It is customized to each project based on the boundary of the analysis and the level of detail we are at. There is a more detailed list of what is included in each category and scope level as well if anyone is interested. We are hoping this kind of thing could become an industry norm so we can legitimately compare projects and establish more relevant baselines with a simple-ish graphic. We also think that ‘empty’ categories can be backfilled with industry average data so our embodied carbon reductions are comparable to one another. For example, a 50% reduction in structure and envelope is very different than a 50% reduction across all categories. 2021-11-18 Embodied Carbon Scope Levels.pdf (53.6 KB)
I think that is a great approach – it’s critical to identify those boundaries to facilitate comparable data. I also agree with your approach of incorporating an average value to the empty categories for a more robust understanding of the project’s true carbon footprint.
I’d be interested in seeing the more detailed breakdown of each category’s scope if you are open to sharing that here.
Hi Andres, the attached graphic key is not fully baked, but I’d love to get feedback on it. Any and all comments are welcome, feel free to email me directly at kanderson@lmnarchitects.com or let me know if there is already and industry way of comparing model scope. I’d love it if there was some comparability among industry models. 2022-02-02 Embodied Carbon Scope Levels.pdf (57.8 KB)
Thank you for sharing! I am not aware of any existing frameworks that determine the levels of scope in embodied carbon calculations. I will take some time to think through the document you sent and we can sync on feedback. I really like your idea of backfilling gaps with industry data. That will really allow for fair comparisons across different building typologies given variability of how LCAs are carried out.
Hi all - this is a helpful conversation. Kjell - I think it would be incredibly useful to have an upcoming CLF talk on determining scope and setting targets. It’s a very useful framework that you provide, especially backfilling with industry data and other data. The model helps to provide a ramping scope for companies that don’t want to track Scope 3 because there isn’t sufficient data or verification.