BUILDING INTEGRATED CARBON CAPTURE TECHNOLOGY: A SOLUTION TO MEET OUR 1.5 ° C CLIMATE TARGET?
This research study explores the net carbon saving potential of a building integrated carbon capture technology and its financial implications.
The building industry is in a race? global greenhouse gas (GHG) emissions need to peak before 2025 and be reduced by 43% by the end of this decade to stay under the 1.5 ° C threshold (IPCC, 2022). We need to rethink the way we design and build to tackle our carbon emissions in a holistic way, we need to focus on whole life carbon emissions (both operational and embodied). What if our buildings could become carbon absorbers? There are natural ways to remove carbon dioxide from the atmosphere, like forests and oceans. But we also have technological means of carbon removal, including direct-air carbon capture (DAC). Innovators are already developing carbon removal technologies that are integrated into building systems. What if we could piggyback on existing building HVAC systems to capture carbon?
To explore this question, we partnered with a Helsinki-based start-up Soletair Power, along with the UK architect team at Gensler to test one of these emergent technologies in a UK context applied to commercial buildings.
We split the study in 2 parts; Part I (Inhale) which explores the carbon captured part within the building and Part II (Exhale) which looks at the carbon usage once captured. For Part I, we were interested in the following questions: Does it save carbon over its lifetime (over the 20 years) when looking at the CO2 captured, the embodied carbon and its operational carbon impact (the unit requires electricity to function)? Where is the technology viable? At what cost (over the 20 years) ? This technology is not cheap currently but is likely to be reduced by 50% in the next 5 years. How does it do compare against standard DAC plants and renewable options such as PV and wind energy? We did not attempt however to quantify the effect on internal air quality. .
This first part of the study was based on manufacturer data (the unit is installed on various sites). We used the CIBSE TM65 methodology for embodied carbon calculations. Net carbon balance as well as net cost balance over the whole lifecycle were calculated.
When looking at part I only, we found out that the technology can reduce carbon emissions when the grid is decarbonised. Net carbon savings can only occur if it is installed in a place with a grid carbon factor below 0.11 kgCO2e/kWh (p.21).
The technology has the potential to improve significantly from both a cost and carbon perspective in the next 5 years (p.26 - 29). It will require the manufacturer to downsize the equipment and improve the energy efficiency. The fact that the technology can be widely scalable (only requiring space provision in the plant room) and reliable (clear visibility on the amount of carbon captured) makes it all the more interesting. Factoring potential revenues of this technology (via selling carbon or improving productivity) could make it more financially viable in the future, but this wasn't explored as part of this study.
This first part of the study also builds on our previous work done about whole life carbon implications of rooftop solar photovoltaics (PV) installations in the UK. This enabled us to compare the two technologies on the same commercial building (p.31). We also included other comparisons against wind energy and standard DAC plants (p.32).
Although net carbon savings from PV appear less significant for this technology, both technologies are needed and complementary. To get to the technology’s full potential, we need renewables first. Installing PVs widely, which are more financially viable currently, also gives us time to reduce cost and embodied carbon of the carbon capture equipment. We think this technology could be explored in high-ambition projects where onsite PV isn’t an option and in regions where clean grids allow a beneficial carbon balance.
To conclude this first part of the study, the technology is not mature yet but shows promise. It seems likely that it will enable us to reduce carbon emissions once current renewable energy options are no longer making a carbon impact on a clean grid. The next phase of the project is to explore applications of captured CO2, to understand if the technology is indeed a solution to meet our 1.5°C target.
Context
Approach
Technology Review Now and in 5 Years
Comparison Against Other Renewables
Conclusion
Limitations & Assumptions
Acknowledgments
Global greenhouse gas (GHG) emissions need to peak before 2025 and be reduced by 43% by the end of this decade to stay under the 1.5°C threshold [1].
Buildings are responsible for 40% of global carbon emissions [2]. Designers have a responsibility to design low-carbon buildings.
This work explores what else we can have in our designer toolkit to ensure 1.5°C design proof buildings.
NORTHERN HEMISPHERE SUMMER TEMPERATURES (750 TO 2020)
In our effort to fight climate change, we need to approach our designs’ carbon footprint holistically: we need a whole-life carbon approach. We need to understand the carbon impact across the building’s whole life cycle, meaning the embodied and operational carbon impact to make sure we are specifying the right low-carbon design solutions and technologies.
In 2021, Introba explored the whole-life carbon implications of rooftop solar PV in the UK [3]. This year we wanted to explore other technologies.
According to the International Energy Agency (IEA), Direct Air Carbon (DAC) capture will play a key role in the decarbonisation of the global energy system. In their 2050 Net Zero Scenario, DAC technologies capture more than 85 Mt of CO2 in 2030 and around 980 MtCO2 in 2050 [4].
There is a broad scientific consensus that the target of the Paris Agreement of the 2015 Climate Conference (COP21) requires not only a massive reduction in GHG emissions but even up to 30Gt per year of negative emissions [5].
Some manufacturers like Soletair Power are working on a technology that captures carbon from the air in your building.
The Soletair Power Building Integrated Direct Air Capture of CO₂ technology, currently manufactured in Finland, is a unit you place in the building’s plant room, connected to the ventilation system that absorbs CO2 from the air through a sorbent. It requires energy to function.
We explored the maturity of this technology at present.
Does this kind of technology save carbon? At what cost?
Now and/or in 5 years?
Where is the technology viable? What are the thresholds to make it viable?
How does it compare against photovoltaics, standard Direct Air Capture (DAC), and wind energy?
To be viable against climate change, we should aim to be in the green zone, capturing more carbon than the carbon emissions resulting from operating, building, and recycling/disposing of the unit.
Ideally, the technology should be in the top right quadrant, to pay back both in cost and carbon.
We looked at the technology now versus in 5 years from now versus putting photovoltaics on the roof of our fictional office building now. In Part I of this study (Inhale), we have only explored the question of viability until the carbon is captured.
Carbon captured (B1)
– Operational Carbon (B6)
– Embodied carbon (A1-A4, B3-B4, C2-C4)
Carbon offset
– Capex – Opex
?
The scope and boundary of the net cost and carbon calculations are:
• Scope: Soletair Power patented Technology (3x3x3m)
• Where: in a 2,000m2 office building in the UK
• Study period: over the next 20 years (2022-2041)
• Embodied carbon scope: upfront carbon (A1-A4), repair (B3), replacement (B4), end of life (C2-C4), as well as refrigerant leakage (B1 & C1). CIBSE TM65 methodology [6] was used. The amount of carbon captured was given by the manufacturer and is accounted in B1.
• Operational carbon scope: energy (B6) based on manufacturer data from actual projects.
More information on limitations and assumptions here.
Soletair Power’s patented ‘Building-HVAC-Integrated CO2 Capture Technology’ operates inside a building’s plant room. It is connected to the HVAC system. The ventilation air goes through the unit where CO2 is captured by a sorbent. The process requires electricity. The output is water and pure CO2 which can the be liquefied. The unit might require additional infrastructure such as storage, depending on the use of the CO2, but this is outside our study scope.
The unit explored has a capacity of 3m³/s, which equates to the typical outside air ventilation rate for 2000m² of office floorplate. The unit has a self- contained fan which overcomes the internal pressure drop of the equipment. It can be installed on both existing and new buildings if there is enough space.
As the technology consumes electricity to capture carbon, results depend on the grid decarbonisation scenario.
Based on current grid carbon factor and assuming no decarbonisation scenario over the next 20 years, this is what it looks like: the technology is not making net carbon savings.
CURRENT TECHNOLOGY:
• CAPTURE 50 kg CO2 /DAY
• 93% EFFICIENCY – 20 YEARS
• WEIGHT 11 tonnes
• CAPEX £ 500K
*: no inflation (0.28 £/kWh energy price)
• OPEX £ 623K – 20 YEARS*
• ENERGY USE 5kWH/ kg CO2e CAPTURED
• HEAT PUMP WITH R410A
If you are optimistic: the technology does save net carbon over the next 20 years.
Using BEIS average carbon factor over the next 20 years 0.055 kgCO2e/kWh (Greenbook 2022)
The decarbonisation of the grid makes a huge difference. For this study we are using BEIS values from the Greenbook 2022, using a predicted average over 20 years.
CURRENT TECHNOLOGY:
• CAPTURE 50 kg CO2 /DAY
• 93% EFFICIENCY – 20 YEARS
• WEIGHT 11 tonnes
• CAPEX £ 500K
*: no inflation (0.28 £/kWh energy price)
• OPEX £ 623K – 20 YEARS*
• ENERGY USE 5kWH/ kg CO2e CAPTURED
• HEAT PUMP WITH R410A
The tipping point is 0.11 kgCO2e/kWh.
ELECTRICITY CARBON FACTOR (KGCO2E/KWH)
If over the next 20 years, the grid carbon factor is on average below, the technology will save net carbon over its life cycle.
EXAMPLE OF COUNTRIES WITH AN ELECTRICITY CARBON FACTOR <0.11kg CO2e/kWh [ source 8 ]
• ICELAND 0.027
• SWEDEN 0.039
• COSTA RICA 0.04
• FINLAND 0.058
• ONTARIO (CANADA) 0.057
• FRANCE 0.064
• YUKON (CANADA) 0.071
Current Soletair Power Technology carbon impact over the next 20 years in a UK office building
New sorbent and some parts are repaired/replaced
The operational carbon decreases as the grid decarbonises
Total net carbon savings in 20 years: 104 tCO2e
The amount of carbon capture decreases a little over time due to the decrease in efficiency of the sorbent
Starts saving carbon
years
Embodied carbon (A1-A4, B3-B4, C2-C4 + refrigerant leakage) Operational carbon (B6) Carbon captured (B1) Net carbon
The average carbon emissions per head for Europe is about 10 tCO2e per year [9].
Currently, the CAPEX + OPEX cost represent:
• Per tCO2 captured: £3k
• Per tCO2 net savings: £11k
• Per m2 per year cost: £28
CURRENT TECHNOLOGY:
• CAPTURE 50 kg CO2 /DAY
• 93% EFFICIENCY – 20 YEARS
• WEIGHT 11 tonnes
• CAPEX £ 500K
*: no inflation (0.28 £/kWh energy price)
• OPEX £ 623K – 20 YEARS*
• ENERGY USE 5kWH/ kg CO2e CAPTURED
• HEAT PUMP WITH R410A
UK/2000 m² office building/ Over 20 years/ Static calculations*
If electricity price was at £0
As electricity prices are currently very uncertain, we assumed a static cost of £0.28/kWh over 20 years.
But even if the price of electricity was £0, the CAPEX and OPEX cost would still be too substantial compared to carbon offset benefits (assuming £90/ tCO2 - GLA).
CURRENT TECHNOLOGY:
• CAPTURE 50 kg CO2 /DAY
• 93% EFFICIENCY – 20 YEARS
• WEIGHT 11 tonnes
• CAPEX £ 500K
*: no inflation (0.28 £/kWh energy price)
• OPEX £ 623K – 20 YEARS*
• ENERGY USE 5kWH/ kg CO2e CAPTURED
• HEAT PUMP WITH R410A
UK/2000 m² office building/ Over 20 years/ Static calculations*
OPEX need to be reduced and potential revenues could be accounted for
Cost uplift could be reduced by a potential increase in staff productivity (by lowering the CO2 concentration of the internal air) and revenue from the sale of carbon captured. These haven’t been quantified as part of this study.
CURRENT TECHNOLOGY:
• CAPTURE 50 kg CO2 /DAY
• 93% EFFICIENCY – 20 YEARS
• WEIGHT 11 tonnes
• CAPEX £ 500K
*: no inflation (0.28 £/kWh energy price)
• OPEX £ 623K – 20 YEARS*
• ENERGY USE 5kWH/ kg CO2e CAPTURED
• HEAT PUMP WITH R410A
OK, IT MAY SAVE CARBON, BUT HOW DO WE MAKE IT FINANCIALLY VIABLE?
• CAPTURE 50 kg CO2 /DAY
• 93% efficiency – 20 years
• Weight 11 tonnes
• CAPEX £ 500K
• OPEX £ 623K – 20 years*
• Energy use 5kWh/kg CO2e captured
• Heat pump with R410a
• CAPTURE 50 kg CO2/DAY
• 93% efficiency – 20 years
• Weight 5 tonnes
• CAPEX £ 130K
• OPEX £ 376k – 20 years
• Energy use 2.5kWh/kg CO2e captured
• Heat pump with R32
The technology is likely to evolve quite rapidly, managing to reduce cost, overall weight and material used for better efficiency.
With the following assumptions and UK predicted grid in 5 years** the technology is assumed to be able to save net carbon.
TECHNOLOGY IN 5 YEARS:
• CAPTURE 50 kg CO2 /DAY
• 93% EFFICIENCY – 20 YEARS
• WEIGHT 5 tonnes
• CAPEX £ 130K
• OPEX £ 376k – 20 years
50% 75% 40%
• ENERGY USE 2.5kWh/kg CO2
• Heat pump with R32 50% GWP
Starts saving carbon
When it is saving carbon with the technology currently
Total net savings in 20 years:
208 tonnes CO2e
years
Embodied carbon (A1-A4, B3-B4, C2-C4 + refrigerant leakage) Operational carbon (B6) Net carbon Net carbon
UK/2000 m² office building/ Over 20 years/ Static calculations*
In 5 years, the CAPEX and OPEX could drop to:
Per tCO2 captured: £1,5k
Per tCO2 net savings: £2,4k
Per m2 per year cost : £13
TECHNOLOGY IN 5 YEARS:
• CAPTURE 50 kg CO2 /DAY
• 93% EFFICIENCY – 20 YEARS
• WEIGHT 5 tonnes
• CAPEX £ 130K
• OPEX £ 376k – 20 years
compared to now
• ENERGY USE 2.5kWh/kg CO2
• Heat pump with R32a
For a 2000m2 office building, it is unlikely you would be able to put 2000m2 of PV – we explored 2 scenarios: 1-storey and 3-storey building
We compared the technology now and in 5 years against current photovoltaics (PV) options for the same project. It shows PV is currently more financially viable over the next 20 years than this technology but saves less carbon overall.
The PV comparison is based on the Whole Life Carbon impacts of UK rooftop solar photovoltaics installations – studied in this report.
However, revenues from selling carbon for fertiliser or refrigerant purposes as well as potential work efficiency improvement (by reducing CO2 ppm level) could bring this technology above the cost-neutral line and bring in revenues, making it a competitive and relevant technology.
*: no inflation (0.28 £/kWh energy price)
*Over 20 years
**Wouldn’t be able to fit this on the roof or would need to be put it offsite
***Includes civil engineering, enclosures and plant unit overall
This carbon capture technology has the potential in the future to reduce carbon emissions when the grid is sufficiently decarbonised and when adding more renewables will no longer benefit the grid. However, the scale of the carbon savings will be dictated by how the carbon captured will be then repurposed, which we haven’t explored as part of this study.
However, it’s important to highlight we need renewables first. The grid should first be decarbonised with renewables before installing these technologies, which gives time to reduce the cost and embodied carbon of the equipment.
We think this technology could be explored in buildings where PV is not a viable option.
This technology is likely to be relevant in the future in our effort to fight climate change if it manages to reduce energy consumption and material use. The fact that the technology can be widely scalable makes it all the more interesting, it could be explored on both existing and new buildings.
The financial impacts also need to be carefully considered. When photovoltaic panels become more financially viable if, as expected, utility costs increase, carbon capture will become more expensive to operate. This is a reversal of the carbon impact, when photovoltaics will become less beneficial with a decarbonising grid (although PV is essential to achieve this) carbon capture will become more beneficial.
The final implications of potential productivity gain due to lowering CO 2 ppm concentration haven’t been factored in in this study, but could be if thoroughly quantified.
Part I of this study therefore concludes that the technology is not mature yet but shows good promise.
The next phase of this project, led by Gensler, will explore how to use the carbon captured and how it can potentially change the office experience.
The captured CO2 could serve as a carbon feedstock for fuels, fertiliser, low GWP refrigerant, and other value-added products like concrete aggregates (through carbonation). The logistic and manufacturing steps would need to be quantified from a carbon perspective as well to get the full picture.
Imagine a building that harvests carbon to enhance the user experience...
Imagine a building that connects us to our impact...
Imagine buildings harvested from thin air...
The calculations are static. No energy price inflation was factored in as too uncertain, though it is very likely prices will rise.
Only based on one technology and information available from one manufacturer.
Grid decarbonisation predictions are uncertain.
Embodied carbon calculations were carried out using TM65 CIBSE basic calculation methodology (no mid-level method) and don’t rely on an environmental product declaration (EPD).
Comparison against wind and DAC were made using available publications, so there may be discrepancies in the method.
No strategies have been scrutinised on what to do with the carbon once captured yet (Part II of the study will focus on this question).
Context Section
[1] IPCC, 2022, website - link
[2] WGBC, 2019, website - link
[3] Hamot L. et al., 2022, Whole Life Carbon of Photovoltaic UK rooftop solar Installations, Elementa Consulting whitepaper - link
[4] IEA, 2022, Direct Air Capture Executive summary - link
[5] Smouchka E. et al., 2016, Life Cycle Analysis of the Embodied Carbon Emissions from 14 Wind Turbines with Rated Powers between 50 Kw and 3.4 MW, ResearchGate article– link
[6] CIBSE, 2021, TM65 Embodied carbon in building services: calculation methodology – link
Technology review Section - Grid carbon Factor
BEIS UK conversion factors 2022 - link
Electricity Maps | Live 24/7 CO₂ emissions of electricity consumption (used for other countries than the UK) – link
Comparison against renewables Section – PV
Hamot L. et al., 2022, Whole Life Carbon of Photovoltaic UK rooftop solar Installations, Elementa Consulting whitepaper – link
Comparison against renewables Section – Wind energy
A: Website Wind energy the facts – link
B: Smouchka E. et al., 2016, Life Cycle Analysis of the Embodied Carbon Emissions from 14 Wind Turbines with Rated Powers between 50 Kw and 3.4 MW, ResearchGate article– link
Comparison against renewables Section - DAC
A: Deutz S. et al., 2021, Life-cycle assessment of an industrial direct air capture process based on temperature–vacuum swing adsorption, NatureEnergy article - link
B: IEA, Website Direct Air Capture – Analysis – IEA - link
C: Terlouw T. et al., 2021, Life Cycle Assessment of Direct Air Carbon Capture and Storage with Low-Carbon Energy Sources, Environmental Science & Technology - link
Gensler
Thank you as well to :
Nick Jones – Gensler
Richard Palmer – Introba
Rhiannon Laurie – Gensler
Juliette Shobo – Gensler
Andy Stanton – Introba
Soletair Power
Soletair Power
This work was done thanks to the Impact Fund, an internal program at Introba aimed at supporting thought leadership initiatives around sustainability and digital innovations for the built environment. It runs on an annual basis and funds projects, studies, essays and advisory pieces that provide new insights on how we perceive, design and build our human environment. It is an opportunity to reflect, question, think big and offer solutions to make our world more resilient, just, and regenerative.
Click here for more information about the Impact Fund: Impact Fund | Introba
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