Sep 8, 2021
Climate change is a hot button issue in every industry – tackling this global crisis within the built environment means focusing on a practice called Decarbonization. Simply put, decarbonization the reduction of carbon. It also means strategically converting a system in a way that sustainably reduces the emissions of carbon dioxide (CO2).
Lately, decarbonization has taken center stage as one of the top strategies for combating climate change. On the tails of the newly released Intergovernmental Panel on Climate Change (IPCC) Report and the U.S. Infrastructure Bill, decarbonization within residential and commercial buildings has been getting more attention. Globally, the built environment accounts for 11% of annual embodied carbon emissions. As a positive, there are many forms of eliminating carbon dioxide emissions within the built environment.
As most of the building-related carbon emissions are tied to energy-use, reducing energy consumption through energy efficient design techniques is a critical step. Additionally, construction practices and material selection can further reduce carbon in the building.
The California Energy Commission (CEC) recently adopted one of the most stringent statewide energy efficiency standards currently up for approval in the U.S. Once approved by the California Building Standards Commission, the new code will incentivize all-electric new construction and renovations, as electric heat pumps and electric appliances drastically reduce greenhouse gas emissions.
Space heating, plug loads and domestic hot water consume significant pieces of energy consumption in buildings. By using Energy Management Systems (EMS) and Building Management Systems (BMS), those loads can all be measured, monitored, and shifted to reduce over-consumption, resulting in reduced carbon emissions and costs.
Another step to embrace carbon reduction within the building design is the use of renewable energy both on-site and off-site. Additionally, (while not the preferred method) another option is to purchase carbon offsets where the purchase facilitates someone else to remove greenhouse gas emissions from the atmosphere to compensate for the emissions occurring due to the operations of the building.
Once the building’s demand for primary resources have been reduced via the design and optimization process, the decarbonization focus turns to construction practices. Through construction optimization and material decarbonization, the built environment can chip away at the carbon footprint.
Utilizing alternative heavy equipment like electric instead of diesel, selecting more sustainable materials, and a shift toward prefabrication of buildings can optimize construction practices. Prefabrication allows standard components of a structure to be created off-site in a manufacturing facility then transported to the final building site. It reduces labor time on site, material waste, transportation impacts, and optimizes the use of primary resources for construction. All of these factors contribute to a reduction in the life-cycle embodied energy and carbon in the building.
Material decarbonization is the final strategy in reducing carbon emissions in construction. Below are some of the top materials being utilized in this process.
Surprisingly, the steel industry is one of the top three contributors to CO2 emissions. Despite steelmakers almost perfecting the use of recycled materials in steel production, this material is still energy intensive and high in embodied carbon. With the continued pressure of decarbonizing building materials, steelmakers are looking at innovative strategies such as carbon capture and heightened reuse of construction steel using a circular economy method.
The most progressive of the decarbonization strategies is a hydrogen-based steel production process that would eliminate almost all reliance on coal (which can be attributed to 70% of the greenhouse-gas emissions in the steel industry). The hydrogen-based production model would make producing steel almost carbon-neutral.
Like steel, the concrete production industry is one of the top three contributors to CO2 emissions. But, unlike steel, emissions from the production of cement and concrete result from chemical reactions in the manufacturing process, not fuel combustion. That key difference makes decarbonizing concrete more challenging. New technology has emerged that captures and utilizes CO2 across multiple manufacturing phases. Another strategy, carbon mineralization, captures the CO2, and injects it into the concrete – permanently locking away the emissions. The concrete industry is also exploring carbon storage. This means CO2 is captured and stored securely in long-term geologic reservoirs (and not used for enhanced oil recovery).
The use of mass timber as an alternative to concrete and steel is a trending topic in the built environment. Not only does mass timber encompass prefabrication techniques reducing carbon through avoided materials and primary recourses uses, but the material itself serves as a carbon sink, reducing the amount of carbon in the construction process.
If the built environment wants to assist in mitigating climate impacts, stakeholder collaboration for decarbonization strategies is a top priority. With all the disruptions in the construction industry right now, sustainability is still pressing ahead, with systematic change rapidly approaching. Every part of the design and construction process will face transformative changes to decarbonize the spaces where we live, work and play.