Climate change is one of the preeminent issues facing society. As a result, construction companies and building owners have made efforts to reduce the impact that buildings have on the environment. To date, the main focus has been on reducing carbon emissions once the building is up and running. More and more, though, we’re shifting to reducing carbon emissions during construction.

The construction industry emits more carbon than meets the eye. Much of that is embodied carbon — carbon dioxide emitted into the atmosphere as a result of manufacturing, transporting and using construction material on a job site. One construction material that emits large amounts of carbon dioxide is Portland cement, the main ingredient in concrete and an integral part of almost every building project. This cement is produced by burning limestone in kilns. Bringing those kilns to between 2,300 and 3,000 degrees Fahrenheit requires a massive amount of energy, and the combustion and chemical reactions involved release a large amount of carbon dioxide.

Concrete is a significant source of embodied carbon in construction projects. Our construction and design experts have researched several ways to lower carbon. Some alternatives replace a portion of Portland cement in the concrete mix with other materials that produce less carbon during manufacturing. Others have carbon dioxide injected into the mix, permanently sequestering it while also increasing the concrete’s strength. For the new east deicing apron at YYC Calgary International Airport, we used concrete with injected carbon and offset total carbon by 160 tons.

We’re also keeping a close eye on the steel industry. Although the options for low-carbon steel are limited at this point, some steel manufacturers are altering their manufacturing processes to lower their carbon emissions through offsets and renewable energy. As more low-carbon steel options become available, our teams will be eager to implement this exciting development.

Across North America, regulations and building codes are changing to address embodied carbon emissions. In Vancouver, the local government enacted legislation aimed at reducing embodied carbon associated with new builds by 40% by 2030. The Buy Clean California Act establishes limits on carbon emissions associated with the production of structural steel, concrete reinforcing steel, flat glass and mineral wool board insulation for new public works projects in the state.

Meanwhile, the Canada Green Building Council, the U.S. Green Building Council and the International Living Future Institute offer net-zero certifications. And the World Green Building Council’s Net Zero Carbon Buildings Commitment calls on the construction industry to decarbonize the built environment by discontinuing the use of fossil fuels as quickly as practicable and to ensure that “new developments and major renovations are built to be highly efficient, powered by renewables, with a maximum reduction in embodied carbon and compensation of all residual upfront emissions.”

As targets evolve, we continue to work with clients to determine the most effective ways to decrease embodied carbon and operational emissions. We work with our partners to build projects that exemplify our innovative carbon reduction strategies and highlight the power of collaboration. These include the following:

• Ken Soble Tower at 500 MacNab (Hamilton, Ontario) underwent a deep retrofit that reduced greenhouse gas emissions by 94%.
• Roam Transit Operations and Training Centre (Banff, Alberta), a Gold-certified LEED project became one of the first transit storage and maintenance buildings to achieve Zero Carbon Building Standard Design certification from the Canada Green Building Council.
• Burwell Center for Career Achievement (Denver, Colorado), the first 100% mass timber structure in the state, provides a lighter environmental footprint due to its ability to sequester carbon and its exceptional thermal performance.
• Lakeside Branch Library (San Diego, California), the library is designed to meet Zero Net Energy building standards and is targeting LEED Gold certification and Living Building Challenge Zero Net Energy petal certification.  

The ultimate goal for new building projects is to reach net zero carbon. This means that carbon dioxide emissions will be eliminated or offset in other ways during the construction and operation phases. The World Economic Forum identifies four key trends leading the charge toward net zero carbon buildings:

• Decarbonization of the electric power grid
• Electrification of building space and water heating
• Efficiency improvements to reduce energy demand
• Digitalization to provide flexibility in meeting the needs of both building occupants and the energy grid

Of course, cost is always a major concern for our clients, and some of these sustainable options are more expensive up front. But these strategic capital investments will often result in long-term savings. The World Economic Forum notes that “every dollar spent on energy efficiency returns $3 over time and saves $2 in energy supply investment.” So, for example, if we can reduce the carbon intensity in concrete by 25% to 50%, we can reduce the overall embodied carbon emissions of a project by 12% to 25%, while adding only 0.1% to 0.5% to the project budget.

Embodied carbon is the next step along the path to net zero carbon buildings, and it’s the next big frontier for the construction industry. Our experienced teams of innovative thinkers are here to help clients reach their net zero goals.