Material use and its impact on Carbon Neutrality

Our industry is engaged in an important dialogue to improve sustainability through ESG transparency and industry collaboration. This article is a contribution to this larger conversation and does not necessarily reflect GRESB’s position. Please refer to official GRESB documents for assessment related guidance.

The Intergovernmental Panel for Climate Change (IPCC), the United Nations body for assessing the  science related to climate change, just published the first part of its Sixth Assessment Report on climate  change, disclosing major and inevitable future climate-related risks due to global warming. The report urges politicians and industrialists to take measures towards limiting the impact of climate change. The  real estate sector plays a major role in climate change. According to the European Academies Science  Advisory Council (EASAC), in 2021, buildings will be responsible for 25% of the European greenhouse  emissions and for 40% of the European energy consumption. We must roll up our sleeves and work together to ensure a liveable future.  

The overall carbon emission of a building can be divided into embodied carbon and operational carbon (see also Figure 1). Embodied carbon is stored in the materials and has an impact mainly during the  construction and end-of-life phase of a building, while operational carbon is mainly of importance  during the use phase. Operational carbon is typically the energy consumption of a building. A strong focus on increasing the energy efficiency in the construction sector has been put forward in recent years. Therefore, the carbon emitted in the operational phase decreased drastically. When it comes to  material efficiency, regulations are less strict. At SuReal, we approach the carbon emission of a project  as a combination of both operational and embodied carbon. A focus on also reducing the embodied  carbon reinforces energy neutral ambitions and leads to lower carbon buildings over their lifespan.  

Figure 1 Embodied and operational carbon (© SuReal) 

To help reduce the embodied carbon, SuReal developed a specific method, focussing on  interventions during the (early) design stage and a thorough collaboration with the entire team  (architects, engineers, contractor, client,etc). The aim is to bring together all the input of the different  team members in order to choose the most appropriate material and this at a stage in which the cost  and planning implications are as low as possible.  

Life Cycle Assessment (LCA) studies are done to quantify the environmental impact of a material throughout different stages, including the raw materials extraction, the production and manufacturing  process, the use and end-of-life scenario. These studies are used on a building level to identify hotspots  materials which have the highest impact and on material level to compare different solutions. This  approach is in line with the GRESB credits DMA2.1 “Life cycle assessments” and DMA2.2 “Embodied  carbon disclosure”. 

The LCA results are brought together in a material matrix that facilitates a comparison on different  levels. The LCA result is an important indicator in this, but doesn’t include everything. For example, it  doesn’t show the circularity of a product. What happens when the building reaches its end of life or  modifications are needed? Can the material be easily dismantled and re-used elsewhere? Or can it be  recycled? Other indicators that are included in the decision making process are the health and  wellbeing of the building users (VOC’s, thermal comfort, biophilia), technical requirements (fire  resistance, stability, thermal insulation, weight, acoustical performance), architectural and  esthetical implications, economic feasibility and practical implications (planning). Bringing together all  these different aspects from the beginning increases the chance that alternatives with a lower  environmental impact will be chosen. This approach is directly in line with GRESB credit DRE1 “ESG  strategy during development”.  

Alternatives that have a lower embodied carbon footprint compared to building as usual:  

1. Preservation of the existing reduces the need for new materials. As the production of a  building material is responsible for most of its carbon emission, preserving existing (parts of)  buildings can decrease emission of GreenHouse Gases significantly. 

2. Urban mining is the action of extracting materials from existing products and waste instead  of having to extract the raw materials from natural reserves.  

3. Wooden materials normally have a lower environmental impact compared to cement based  materials. Biogenic storage is another advantage.  

4. Optimising the recycled content of materials can save significant amounts of carbon.  However, it’s important to keep in mind that recycling processes sometimes also have a high  environmental impact.  

5. Dismountable materials will reduce the need for new materials in the future, when  adaptations will be needed.  

Figure 2 Optimize preserved, reused, recycled and dismountable materials (© SuReal) 

These elements are examples of possible ways to lower the embodied carbon of materials, but they  are always examined case by case and considering all aspects as discussed above. Sometimes, a  recycling process has a very high impact, or a reusable material has big health disadvantages, or  much more wood would be needed for a specific element resulting in a higher impact.

By balancing LCA results and the circularity of a material with other indicators in an early stage,  SuReal allows projects to reduce their embodied carbon emissions drastically. In combination with  thorough measures for energy efficiency, this can result in nearly carbon neutral buildings. We  strongly believe that this approach of considering both embodied and operational carbon emissions  can mitigate the buildings’ environmental impact on the long term, over their entire lifespan. A  carbon neutral building is ambitious, but feasible with the right approach and tools. Aiming for  carbon neutrality will become the norm for real estate projects. 

For more information contact SuReal at info@sureal.be

This article was written by Sunita Van Heers – Managing Director SuReal

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