Embodied and Operational Carbon of the Built Environment

By Gayaneh Giragol

As a result of attending Greenbuild 2022 and participating in the decarbonization of the built environment, I gained insight into the embodied carbon and operational carbon of the built environment.

The average American spends 90% of their time inside a building. The built environment contributes to 50% of annual global CO2 emissions and 41% of U.S energy output. These emissions are labeled operational carbon and embodied carbon.

Operational carbon refers to the total from all energy sources used to keep our buildings warm, cool, ventilated, lighted and powered. Typical energy sources for this purpose are electricity and natural gas, with occasional contributions from fuel oil, propane and wood. Embodied carbon consists of all the GHG emissions associated with building construction, including those that arise from extracting, transporting, manufacturing, and installing building materials on site, as well as the operational and end-of-life emissions associated with those materials.

At present, the building sector CO2 emissions are 72% operational and 28% embodied carbon. It is projected that by 2050, operational carbon will reduce to 51%, however embodied carbon will increase to 49%.

Not only emissions are from operational and embodied carbon, but transportation of building occupants also contributes to emissions.

To achieve zero embodied emissions requires strategies such as renovating new buildings instead of building new ones or using recycled materials and thinking about the end of life of a building and how it will be demolished.

There are also opportunities to include material optimization as LEED Material and Resources credits are intended for and using carbon sequestering materials. Other possible opportunities are to use low carbon concrete mixes and limit carbon intensive materials. Lastly, the industry can use fewer finish materials and maximize structural and operational efficiencies.

Decarbonizing the built environment is now a critical agenda and it is possible to achieve the 2030 challenge with efficiency, electrification, decarbonization and renewable energy.