With the beginning of 2023, the world is getting one year closer to the 2030 Agenda of Sustainable Development Goals. Many of these targets are to some extent related with the construction sector. Buildings have a significant impact on the environment and are responsible for a large part of global carbon emissions. In the following article, you will find out exactly what embodied carbon is and why it should not be disregarded when getting to net zero.
What is Embodied Carbon in Buildings?
Embodied carbon is all the carbon that is emitted during the production of materials and the construction period of a building. This includes the entire lifecycle, from extracting raw materials, transportation, manufacturing and installation, to the demolition of buildings and disposal of the remains. Consequently, the name comes from the CO2 that is stored within all of these materials.
Why is Embodied Carbon Important in 2023?
As mentioned earlier, the real estate industry is a major contributor to global carbon emissions – buildings are responsible for about 39% of it. In order to assess their footprint more accurately it is important to not only consider the operational carbon emissions but also the embodied ones.
Often, only operational carbon is used for estimating a building’s impact on the environment. This would lead to a large portion being ignored when evaluating the global consequences. Out of the total 39% of emissions, operational ones are making up 28% and embodied ones 11%.
With an increasing population, more buildings are required to house them. This would lead to an expansion of construction activities and a higher proportion of embodied carbon. To improve this issue, more accurate estimation methods are necessary.
Operational emissions are emitted during the use phase of a building and include factors such as heating, air-conditioning, appliances, and more. Thanks to devices like smart metres, it is easy to measure and estimate the amount of carbon that is emitted by these technologies. On the other hand, for embodied carbon, it is much more complicated.
How to Estimate Embodied Carbon in Buildings?
Researchers, architects, engineers, and specialised consultants are usually responsible to estimate this amount and have developed strategies to do so with accuracy. There is no international standard on how to assess embodied carbon in buildings, but some methodologies have been provided by the Royal Institution of Chartered Surveyors (RICS) and the Institution of Structural Engineers.
In general, these types of emissions are calculated by taking the quantity of a specific construction material and multiplying it by a factor. This factor is called the “carbon factor” and presents the amount of embedded carbon for a wide variety of resources and products. Its unit is kgCO2e/kg, or in other words: the carbon emissions in kilogram, per weight of a material in kg.
Let’s take a look at an example of how to calculate the embodied carbon for a material. A structure uses 10 tons of steel reinforcement bars, these have a carbon factor of 1.99 kgCO2e/kg. If we now multiply 1.99 by the 10.000 kg of steel, we get total carbon emissions equalling about 19,900 kg or 19.9 tons.
In some cases, a material can actually store more carbon than it produces. This results in a negative carbon factor. Therefore, by using natural materials with negative emissions, other parts of the building can be offset which helps to reach a net zero status.
What can be Done to Reduce Embodied Carbon?
There are a number of ways to reduce the amount of embodied carbon in a structure or building. As explained before, the CO2 is generated by extracting raw materials, transportation, manufacturing, installation, and other processes.
Therefore, these factors must be made more environmentally friendly. If more and more real estate developers or investors are following these guidelines, a significant amount of stored emissions can be removed from the planet.
1 | Refurbishing Instead of Replacing
One of the best methods to reduce embodied carbon is by refurbishing buildings instead of demolishing and replacing them. This is due to the high amount of energy that is needed to deconstruct the property. Furthermore, many of the materials cannot be recycled efficiently which leads to tremendous waste in materials that store carbon.
When an office or multifamily residence gets demolished it often makes room for a new building. This means that construction materials are needed and that an increase in emissions is inevitable. On average, refurbishments can save between 50-75% of embodied carbon over a new development.
2 | Using Recycled Materials
Another strategy is to use recycled materials for construction projects. These materials have been manufactured already and therefore store a significant amount of carbon within them. By reusing them, no new materials must be produced which will have a positive environmental impact. Some commonly recycled construction materials are steel, concrete, metals, glass, wood and bricks.
3 | Minimising Transportation Emissions
While extracting raw materials and manufacturing finished products make up most of the embodied carbon, the transportation of these to their desired location is also an important factor. To minimise these emissions, one step can be to use low-emission modes of transportation such as trains. A second way of minimising this type of CO2 is to use locally produced materials. This ensures that the distance between the construction site and the manufacturer is as small as possible.
4 | Using Low-Carbon Materials
When estimating the embodied carbon in buildings we have already mentioned that there are also some materials that can have a negative carbon factor. If new developments utilize these more often, it will be possible to offset other products to a great extent. Low-carbon materials include, for example, wood, bioplastic, mycelium products, or concrete that is carbon-cured.
5 | Creating Buildings with a Long Lifespan
Our last tip on how to reduce embodied carbon is to create buildings that have a longer lifespan. This means prioritizing solutions and technologies that can enhance the life of a property, such as finding a location that is desired by tenants for many upcoming decades or using smart technology to reduce maintenance issues. Furthermore, it is important to design the interior of a building in a way that it allows to be changed for different purposes over time.
Conclusion
Embodied carbon plays an important role in our global goal of getting to net zero. These types of emissions are often ignored when talking about the environmental impact of a building. While they are difficult to calculate, there are some methods of estimating embodied carbon. This is usually done by multiplying the weight of a material by a defined carbon factor. Real estate companies can take a number of actions to lower the amount of emissions stored in buildings. Most importantly, it is necessary to refurbish properties instead of replacing them.
If you want to learn more about the future of commercial real estate, including topics such as sustainability & ESG, PropTech, architecture, development and investment, feel free to take a look at our other articles on Smart CRE. Here you will also find insights into the job market and how to start a career in real estate.
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