My interest in Direct Air Capture (DAC) applied to buildings came in two ways. The most philosophical reason, if you may, is about our relationship with carbon, meaning greenhouse gas emissions converted into its CO₂ equivalent. I see the whole industry in this race to net zero carbon. Don't get me wrong; I am 10,000% supportive and, in fact, active in our effort to carve out the greenhouse gas emissions associated with our designs and buildings, but zero carbon, really? Besides thinking that zero as a target isn't sexy and appealing, it demonizes carbon. Carbon is a good thing. We are made of carbon; it is essential to sustain life and the universe in general. Our relationship with carbon is messed up; that's what I think, and we should work on that.
Reversing our approach to carbon and considering it as a resource all around us in the air is appealing. Oceans, trees, and plants use carbon to grow and thrive (but don't forget that trees reject CO₂ like us at night); why couldn't we imagine buildings that do the same? Transform buildings into living systems—the ultimate goal of an architect-engineer.
The second reason is more associated with my inner critical sense (very French of me, I reckon). In the last year, DAC has become a buzzword, the solution that heavy polluters such as the cement or the oil industry are waving around as the one that will solve everything. The Infrastructure Investment and Jobs Act bill passed in the US announced a significant investment in such technologies in the coming years. Even the respected International Energy Agency (IEA) tells us that carbon capture will play a role in meeting our energy and climate targets.
But when I look at the Orca plant in Iceland, for instance, I see a vast amount of resources (primarily metals that are hard to extract and process) and a tremendous amount of energy required to function. So, is it really the next go-to when looking at the bigger picture? Isn't it another way to rely blindly on technology and create unintended consequences?
This explains why it caught my attention when architects from Gensler's London team contacted me about a relatively small technology (3x3x3m) compared to current DAC plants that could be plugged into buildings existing ventilation systems to capture carbon. Does this new baby save carbon over its whole service life? At what cost? (Because, let's face it, cost is currently the main "C" that rules our world.) What would be the right conditions for such technology? How does this compare against other renewables? We contacted a Finnish manufacturer, Soletaire Power, who had already developed and installed the technology in some buildings and was happy to share their data with us.
We secured some funding through the Impact Fund, to explore how the technology captures carbon within a building (Part 1—Inhale). The question of what happens to the carbon next will be explored by Gensler as the next step (Part II—Exhale). To look at the whole-life carbon impact of this unit, we had to calculate the operational carbon associated with energy use, the amount of carbon it could capture, and the embodied carbon impact associated with making, installing, maintaining, and dealing with the end of life of the unit. We did the study in a UK context over the next twenty years. For embodied carbon calculations, the manufacturer worked on detailing the material composition breakdown of the unit for us to do CIBSE TM65 calculations. I am the co-primary author of this methodology. We experimented with a similar process when looking at the whole-life carbon impact of rooftop UK solar photovoltaic installations. So, we felt confident in our method. The aim was to be as holistic as possible regarding carbon and correctly map out the emissions and removals in the next twenty years.
The technology is not exactly there but looks promising in the coming years. It can save net carbon if the grid is decarbonized enough. Therefore, it is essential to focus first on decarbonizing our grids and investing in renewables such as photovoltaics. It will give us time to reduce the cost (the unit today costs half a million euros—ouch!) and the equipment's embodied carbon (by making it leaner).
To be clear, there is no competition between renewable technologies; they are, in fact, complementary. Where and when renewables become less beneficial with a decarbonizing grid, carbon capture within buildings will be more beneficial to cover the rest of the carbon emissions we need to carve out to meet our climate targets. In the case of buildings where photovoltaics can't be used because of limited roof area or shading context, carbon capture technology could be interesting sooner. The fact that the technology can be widely scalable, as it only requires space provision in a plant room and most buildings have ventilation systems, also scores a point.
The technology also reduces the parts per million concentration of CO₂ within the building. This might have some cognitive health benefit—although we didn't lean too much on this point as the literature is currently unclear (five papers say yes, five say no).
Another benefit of this technology is that it could offer an alternative to current offset frameworks. More scandals appear every day in newspapers about fraudulent offsets or at least inefficient ones. If people want to pay off their impact (after doing all they can to reduce it, let's be crystal clear), this technology could be a more useful investment, in my view—something to chew on.
The last thought, which is not minor, is, what do you do with the carbon you captured? If it is to bounce it back into the air, what's the point? This would be the next phase of the exploration. We have some leads: use it as a refrigerant as an alternative to the high Global Warming Potential (GWP) options typically used (learn more about this in the paper I co-authored here), use it to make fertilizer, or even use it as an aggregate to make furniture or other materials. Sounds promising, doesn't it? Yes, but all of these options require an infrastructure and logistics aspect that need to be studied in detail before concluding this technology is, indeed, a viable one.
So, is this only half a conclusion, then? Yes, but that doesn't mean we should stop exploring it.
This technical review explores building-integrated carbon capture technology from a whole-life carbon and cost perspective over the next twenty years in the United Kingdom.
Developed in partnership with architects at Gensler and Soletair Power, a manufacturer who produces and installs carbon capture technology, this paper explores this technology's potential now and in the next five years.
Will building-integrated carbon capture be a solution in our design toolkit to help meet our 1.5 °C climate targets?
Louise Hamot is in charge of Introba’s global research and development and thought leadership program around sustainability. She is in charge of the Impact Fund for sustainability, supervising the projects as well as being actively involved. In parallel to this, she has been leading the life cycle practice, supporting global teams in low carbon assessment, and advising architects and clients on design strategies to minimize their environmental impact.
Louise is well known for her work around the whole life carbon of building services/MEP. She is the primary author of different industry standards such as CIBSE TM65, a co-author of the upcoming RICS Whole Life Carbon Professional Statement, and is involved in several international industry collaboration working groups, for instance: Low Energy Transformation Initiative (LETI) and WLCN (UK), ASHRAE decarbonization taskforce (US) and MEP 2040 challenge (CLF).
Louise brings an international vision and, as both an architect and an engineer, a holistic understanding of the built environment.
Oct 20, 2023
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