What is Embodied Carbon?

The amount of carbon (CO2e) produced in the life cycle use of a product or material. Embodied carbon is concerned with the impact of construction materials through raw materials extraction, transport, processing, assembly, use and end of life. The RICS has created this useful lifecycle plan from EN 15978, highlighting the need to consider the product, construction, use, end of life and reuse/recycle/recovery stages.

Case studies

The ZCRI and FCB Studios are jointly developing an approach to assessing the embodied carbon impact of refurbishment in listed and historic buildings. This work will be focused on developing a new set of data and emissions factors for heritage buildings built within the last 100 years in the UK. This data will be used by architects to assist in considering the whole life carbon impact of re-use, recycling, demolition and refurbishment of heritage building for modern day use. OneClickLCA will be used for the analysis. Further details to follow.

The ZCRI is working in collaboration with the Everyman theatre to exploring the embodied carbon impact of construction materials used. We started by obtaining a full and comprehensive Stage 4 cost plan (consisting of over 1,000 components), provided by CharcoalBlue and created by the Quantity Surveyor (Gardiner and Theobald). This a comprehensive list of all the new and reclaimed items (from the previous theatre) used in the construction of the theatre (including Foundations, Frame and Floors, Internal Planning, External Walls, Engineering Services and the Roof). Next, it was necessary to generate emissions factors for every listed component to discover the embodied carbon impact. All emission factors collated are EN15804 verified and standardised Environmental Product Declarations (EPDs) given some confidence in the results. The list of components used in the study has independently been checked by the Architect (Haworth Tompkins), the Structural Engineers (Alan Baxter & Associates) and the Services Engineers (Waterman Group). Read out storyboard here.

SIPs construction – Bushra Al-Ali (PhD student) is testing the whole life impact of a new type of gas free, 100% electric, Structurally Insulated Panel System (SIPs) home. Simulating alternative renewable energy options using DesignBuilder software.This study will become increasingly crucial as the UK aims to find solution to reduce the overall carbon footprint in the construction industry and reach NZC standards. While most studies have focused on clean energy to reduce the carbon impact of Modern Methods of Construction (MMC), very few non attempted a holistic approach to include a whole life carbon impact of the this new method of construction using magnesium oxide SIPs. Click on this storyboard to find out more.

Sustainable energy technologies are frequently considered for use with buildings in order to reduce their environmental impact. However, each technology will come with its own associated embodied carbon, which might potentially represent a significant proportion of a building's total embodied carbon impact. There is a need for further studies on the embodied carbon or CO2 equivalent (CO2e) impact of sustainable energy technologies and it is important to understand how they contribute to the total CO2e budget of a building. Life Cycle Assessment (LCA) is used for the CO2e calculations and this paper has reviewed a significant number of existing studies. The results show that LCA methodologies can and do present information which has a significant degree of inaccuracy. Furthermore, the impact of some technologies can significantly increase the embodied CO2e impact of modern low to zero energy buildings. Considering the whole life CO2e impact of each aspect of a building is crucial for the successful creation of a truly low to zero carbon building. Many current studies omit the CO2e impact from sustainable energy technologies. This leads to results which are under representative and misleading.Read our open access journal paper on the embodied CO2e of sustainable energy technologies.

There is global emphasis on the creation of zero energy and therefore zero carbon buildings. The vast majority of work is focused on reducing the so called “operational” energy in buildings i.e. investigating methods to reduce energy consumption within the building, use more efficient equipment and source energy from zero carbon renewable energy sources.  There is less work undertaken on measuring the “embodied” energy of a building i.e. the life cycle impact of materials and products.  Moreover, there is even less research into the impact of new sustainable technologies that are used to replace existing systems. It is this latter point that is investigated in this chapter. The results show that the impact of new sustainable technologies is significantly less than conventional systems, when compared on a whole life basis.  However, each development and building is unique with a combination of technologies commonly used, therefore generalisations should be avoided.  It is recommended that it is mandatory for all sustainable technologies to have an Environmental Product Declaration (EPD) to enable the decision maker to make the best informed choice possible. Read our chapter in this book entitled Embodied Carbon in Buildings.

Mexican GovernmentRoberto Cruz (PhD student). The aim of the research, funded by the Mexican Government, is to produce a new framework and model for zero energy housing. The city of Puebla is the fourth largest metropolitan area in Mexico with over 2 million inhabitants, and it has the highest annual population growth rate in the country. This research is looking into how a regulated urban growth, together with alternative construction materials could positively impact fast-growing cities like Puebla. Roberto’s work aims to comprehensively analyse the embodied emissions in conventional construction materials used in central Mexico and compare them to a case study found in the area, a house made of adobe (mud bricks). We are also looking at how urbanization is affecting the heat island effect in the area and how climate change is expected to modify weather patterns. Climate change shows a tendency to increase temperatures in the area, which together with poor construction planning will add to the need for cooling in the city, boosting the stress the country’s fossil fuel driven energy generation has at the moment. By looking into alternative construction practices this research’s end goal is to reduce pollutant emissions coming from the urbanization of the space and to provide passive solutions in the face of climate change in the area.

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