Our industry is engaged in an important dialogue to improve sustainability through ESG transparency and industry collaboration. This article is a contribution to this larger conversation and does not necessarily reflect GRESB’s position.
The climate crisis is now more pronounced than ever. This summer’s widespread droughts contributing to agricultural decline and the growing intensity and frequency of severe weather are evidence that climate change is no longer a future problem. The present climate crisis is prompting business leaders to reduce their environmental impact. One of the most effective ways businesses are accomplishing this is through the reduction of their carbon footprint.
Buildings are responsible for approximately 40% of greenhouse gas (GHG) emissions globally. This includes both operational emissions from building use and embodied carbon from construction, renovation, and demolition of buildings. In order to slow global climate change, the built environment needs to achieve both net-zero operational carbon by 2030 and net-zero embodied carbon by 2050. Businesses are now investing in aggressive decarbonization strategies in order to meet the net-zero operational carbon by 2030 goal. In general, the roadmap to achieving net-zero carbon in buildings is outlined in a five-step approach as shown in Figure 1.
Collecting complete and accurate building consumption data represents the foundation of developing a net-zero strategy. Building details and consumption data are used to measure Scope 1 emissions and site operational efficiency. This can be done by conducting energy audits, which measure buildings’ baseline energy use and outline energy conservation measures that can be used to develop an optimization strategy.
Physical upgrades and onsite generation of renewable energy can then be implemented to optimize building efficiency and significantly reduce carbon emissions. Carrying this out across entire portfolios can drastically reduce a business’s carbon footprint and produce considerable ROIs from the application of energy efficiency measures, which in turn enhance asset and portfolio value through reduced operational expenses.
Once carbon emissions have been reduced through onsite upgrades, remaining emissions can then be estimated and offset through the purchase of off-site renewable energy and carbon offsets. Businesses can opt in to Power Purchase Agreements (PPAs) and/or enroll assets in Community Choice Aggregate (CCA) programs to receive off-site renewable energy and offset any residual carbon emissions.
Operational carbon is just one piece of the net-zero carbon puzzle. Embodied carbon – or the greenhouse gas emissions arising from the manufacturing, transportation, installation, maintenance, and disposal of building materials – represents the majority. While operational carbon can be continually reduced through on-site energy efficiency upgrades, embodied carbon is locked in once the building is constructed. It is estimated that embodied carbon will be responsible for 90% of resulting CO2 emissions from new construction between now and 2050. Materials are the main culprit. Unless sufficient action is taken to reduce the emissions associated with material manufacturing, the relative proportion of embodied carbon to operational carbon in buildings will continue to increase as building energy efficiencies improve.
Though all materials have a hand in contributing to a building’s embodied carbon, the structural systems have been shown to have the greatest impact. This is due to the high embodied carbon associated with concrete and steel – two materials that make up the structural foundation of nearly every building. Manufacturing of these materials requires large amounts of combustion, and the necessary energy to power the manufacturing processes often comes from dirty or fossil-fuel intensive grids. Reducing embodied carbon in buildings must start with action in the industrial sector. According to the Global Carbon Project, emissions from the global cement and concrete industries have doubled since 2002.
This can be attributed to a number of factors – including but not limited to increased global demand for construction materials to accommodate population growth, the replacement of aging infrastructure, and the cleanliness (or dirtiness) of grids in manufacturing hotspots like China, where coal remains the main energy source.
Accelerating the transition to a low-carbon industry requires new technologies, processes, and improved efficiencies in energy and materials. The Global Cement and Concrete Association (GCCA) anticipates carbon capture, use, and storage (CCUS) as a solution that could reduce 36% of global sector emissions in 2050.
Though the industrial sector will drive the transition towards reducing embodied carbon emissions in buildings, the construction and real estate industries as a whole can play a significant role in creating a demand for low-carbon solutions. Incorporating embodied carbon as a metric in procurement policies – on a project-, portfolio-, or organization-wide scale – is a good place to start.
This article was written by Carson Smith, Sustainability & Energy Consultant, and Courtney McCracken, Sustainability & Energy Analyst, at Longevity Partners.