Whole Life Carbon
It is urgent changing the approach
Operational Carbon vs Embodied Carbon
The construction, use and demolition processes of buildings are responsible for around 39% of global emissions of Greenhouse Gases (GHG) or simply Carbon, since CO2 is the main component of these gases, which are the main cause of global warming.
These emissions begin at the moment we extract the raw materials that will become construction materials and continue during the manufacturing processes of these materials, their transportation to the site and their installation during the construction of the buildings. These emissions already emitted into the atmosphere before a building begins to be occupied are called upfront carbon, and if we also take into account the emissions that will be produced during the maintenance or repair activities of the building, as well as during the demolition of the building and the transportation of its waste we will be talking about embodied carbon.
The emissions that occur during the use phase of the building, mostly to heat or cool it, are called operational carbon.
The EN 15978 standard structures this complete life cycle of the building, which includes from the extraction of materials to their demolition and recycling, into phases A, B, C, D and we can see in the following figure how they are distributed in each of them. upfront, emodied and operational emissions.
Traditionally, the effort to reduce these emissions has focused on operational carbon. In recent years, we have managed to design and build more efficient buildings that require less energy to heat or cool, and we have also increased the percentage of emission-free energy used in buildings.
However, this effort will not be enough to reduce global emissions to zero by 2050 and achieve the objectives of the Paris Agreement, which aim to limit the increase in global temperature to 1.5°C.”
There is a need to adopt a “Whole life carbon” approach that considers both embodied and operational carbon throughout the entire life cycle of buildings.
Today’s buildings are becoming more efficient and increasingly reliant on renewable energy generated either on-site or from the grid. We can anticipate that these trends will persist in the future, leading to a decrease in the relative contribution of operational carbon emissions.
However, once construction of a building is completed and before it is occupied and utilized, significant amounts of CO2e have already been emitted into the atmosphere during the extraction, manufacturing, transportation, and installation of the materials comprising the building.
Regardless of the energy efficiency measures implemented, such as insulation, solar control, efficient air conditioning systems, and photovoltaic panels, the emitted CO2 already contributes to the greenhouse effect in the atmosphere, thereby exacerbating global warming.
By 2050, embodied emissions will represent nearly half of the total climate impact generated by the new buildings we are currently designing. Therefore, reducing these emissions is imperative to achieve the decarbonization goals necessary for limiting global warming.
It is necessary for developers, designers and policy-makers to modify the current objective focused on the creation of Zero Energy buildings to a more comprehensive concept of Zero Whole Life carbon buildings, where the focus is on reducing global GHG emissions and not only energy consumption.
This Whole Life Carbon approach must also be reflected in the regulatory framework. Current regulations covering environmental aspects are based solely on operational carbon and lack references to the assessment and mitigation of embodied carbon emissions. Exceptions can be found in countries such as France, Denmark and the Netherlands.
The EPBD directive (Energy Performance of Buildings Directive) is the most important regulation aiming at the sustainable performance of buildings in the EU. It should serve as the basis for the legislation of all EU member countries regarding the reduction of GHG emissions.
A new modification of this directive has been approved in March 2024 and for the first time incorporates this whole life carbon approach, including deadlines for its implementation.
1. Full life cycle declaration for new buildings (from 2028): the EPBD requires assessing and reporting through the Energy Performance Certificate the carbon emissions throughout the life cycle in new buildings, using established standards such as EN 15978 and Level(s).
2. National roadmaps and decarbonisation targets: The EPBD requires Member States to develop national roadmaps for full life cycle carbon limits by 2027. It further mandates that a roadmap for decarbonization of the entire building stock.
The EPBD establishes minimum requirements, states can opt for a more ambitious approach by accelerating its implementation and establishing emissions limits for buildings including embodied emissions before 2030, as France or Denmark already do.
What should be the GHG emissions limits throughout the life cycle of buildings built in Spain in the coming years?
While waiting for Spanish Goverment to develop a policy that establishes emissions limits throughout the life cycle of buildings, as established by the new EPBD, we have carried out the exercise of estimating what could be a reduction route that meets the objectives of the Paris and IPCC agreement, keeping global warming at a maximum of 1.5ºC in 2050.
For this, we have used the SBTi initiative (Science Based Targets Initiative).
The Science Based Targets Initiative (SBTi) is a corporate climate action organization that enables companies and financial institutions around the world to play their part in the fight against the climate crisis.
SBTi develops standards, tools, and guidance that enable companies to set greenhouse gas (GHG) emissions reduction targets in line with what is needed to keep global warming below catastrophic levels and reach net zero by 2050.
In collaboration with Ramboll, CRREM, PDw, and DSS+, SBTi has developed specific strategies and tools for the construction sector that allow establishing limits on embodied and operational carbon emissions depending on the location and type of building.
In the figure, we have represented the curves that establish emission limits for the residential, office, and commercial sectors for construction in Spain, according to SBTi. The data for 2025, 2030, 2040, and 2050 are in the following table:”
Is construction in Spain far from meeting these objectives?
There are still no accurate data on CO2e emissions from buildings in Spain by sector and differentiating embodied and operational carbon, the INDICATE project led by GBCE is currently in the process of obtaining these metrics.
We can take as reference the data offered by OneClickLCA in its Carbon Heroes Benchmark program. This establishes an average of 769 kg CO2/m2 of embodied carbon for all types of buildings in Spain in 2023.
Assuming little variation in this value for 2024 or even 2025 and if we compare it with the limits proposed by SBTi, we will see that already in 2025 the limit for residential construction would be exceeded by 90%, 30% for offices and 22% for construction. commercial building.
If the real estate and construction industries do not urgently apply embodied carbon reduction strategies and current emissions levels are maintained, in 5 years the residential, office and commercial sectors will be emitting 300% and 90% more of the limits established by science to avoid global warming above 1.5ºC. by 2050.
Visita our Guide to reducing embodied carbon
If you want to know more:
SBTI: Building sector Guidance
INDICATE: Indicate España por GBCE
BPIE : Reducing carbon emissions over the life of a building: opportunities in the 2022 EPBD recast
Carbon Leadership Forum: Time-Value-of-Carbon
