Applying life cycle assessment and other tools to advance the rapid decarbonization of buildings.

Status: Current

Funding Sources: ClimateWorks Foundation, Landscape Architecture Foundation, CBE Industry Members

Project Objective

This project provides design guidance, tools, and new insights to building industry stakeholders and policymakers to support the rapid and wide adoption of strategies to reduce embodied carbon in the building sector.

Significance to Industry

Embodied carbon refers to the greenhouse gas (GHG) emissions associated with designing, constructing, maintaining and decommissioning buildings. Embodied carbon differs from operational GHG emissions, which come from the electricity, natural gas and refrigerants consumed while operating the building. While operational GHG emissions can vary year to year due to changes in energy supplies and building use, embodied carbon is highly dependent upon decisions made at the earliest phases of building design and construction. Historically, operational energy has been the primary focus for research and policy efforts. However, the carbon embodied in buildings and infrastructure has become a critical concern for rapidly reducing GHG emissions. A wide variety of tools and methods are being applied to this challenge, including life cycle assessment (LCA). This work is being done by a wide range of industry stakeholders, from engineering and design professionals, ESG consultants, real estate developers and academic institutions.

Research Approach

In 2022 CBE launched a new research program focused on embodied carbon. This work builds on the center’s record of successfully launching and growing new research areas, often to fill information gaps identified by CBE Industry Partners, occasionally starting with constrained initial funding yet leading to external grants that support multi-year, multi-project efforts.

This program was started with support from the ClimateWorks Foundation, working in collaboration with the Carbon Leadership Forum (CLF). It is envisioned as an ongoing multi-project effort, with a goal of investigating multiple facets of embodied carbon in buildings, for example material selection for building systems and innovative construction methods for multi-family residential development. The program serves to advance the use of LCA within industry by improving the base level of knowledge within industry, assessing aspects of the built environment that have been largely overlooked to date, and addressing complex issues that are fundamental to LCA methodology and net-zero carbon claims and reporting practices. Below we describe noteworthy projects, both completed and ongoing:

The California Carbon Report: Analysis of Embodied and Operational Carbon Impacts of 30 Buildings

This report documents the use of whole life carbon assessment (WLCA) for 30 new construction projects in California. The authors address the balance between embodied carbon (EC) and operational carbon (OC) over the life cycle of a building, and identify the most significant contributors to EC impacts. The report also describes trends within the building industry that can be used to propose tangible means of reducing the environmental impacts of the North American building stock, and was published in coordination with a separate policy document. CBE’s Matt Roberts was one of the lead authors for this milestone work, done in collaboration with the Carbon Leadership Forum (CLF).

Embodied Carbon Impacts of MEP Systems

Robust information on the embodied carbon of mechanical, electrical, and plumbing (MEP) systems in buildings is greatly lacking, especially when compared to what is known about EC for building structures, foundations and enclosures. To address this information gap, CBE is using LCA to determine the product and transportation global warming potential (GWP) impacts for variable air volume (VAV) and radiant systems in a case study building. The study serves as an initial step in developing benchmarks and impact reduction strategies for building services. The study compares the material substitution from standard piping design practice to PEX pipe throughout for a four-story office building. Preliminary results show that implementing a like-for-like material substitution to PEX leads to significant reduction of GWP impacts compared to the VAV system. This work is complete with a paper in press.

Beyond the Building Footprint: Life Cycle Impacts of Landscape Architecture

California Academy of Sciences green roof

Berkeley researchers and collaborators tour the green roof at the California Academy of Sciences at the project launch.

In partnership with SWA Group’s XL Lab, CBE is performing an evaluation of green roofs, using the California Academy of Sciences in San Francisco as a case study. The research is intended to serve as an initial exploration into sustainability challenges that exist beyond the building envelope, and to identify additional research areas for future collaboration and research. The work is funded by the Landscape Architecture Foundation case study investigation program, and we expect results to be published in the fall of 2024.

CBE is also collaborating with JLG Architects and Atelier Ten on a new study that looks at the inclusion of soil carbon sequestration in whole building life cycle assessments by bridging gaps between the fields of agriculture, soil carbon mechanics, carbon offset principles and LCA methodologies. Preliminary work on this project will be presented at the World Sustainable Built Environment Conference.

Participation on IEA Annex 89

CBE is a participant in an international effort to focusing on the ‘pathways and actions needed by various stakeholders and decision-makers to implement whole life cycle based net-zero greenhouse gas (GHG) emissions from buildings in policy and practice.’ This work is supported by an international association of governments, industry and researchers. This work is scheduled to continue until 2027. (CBE faculty and researchers have participated in previous annexes as noted in this previous post. )

Events and Outreach

As this topic is of great industry to industry, CBE is organizing and participating in many conference and webinar sessions. Some past examples are listed here, and more will be added soon.

Publications and Reports

  • Benke, B., Roberts, M., Shen, Y., Carlisle, S., Chafart, M., & Simonen, K. (2024). The California Carbon Report: An Analysis of the Embodied and Operational Carbon Impacts of 30 Buildings. Carbon Leadership Forum, University of Washington. Seattle, WA.

  • Benke, B., Roberts, M., Lewis, M., Shen, Y., Carlisle, S., Chafart, M., & Simonen, K. (2024). The California Carbon Report: Six Key Takeaways for Policymakers. Carbon Leadership Forum, University of Washington. Seattle, WA.

  • M Roberts, M., Allen, S., Clarke, J., Searle, J. & Coley, D. (2023). Understanding the Global Warming Potential of Circular Design Strategies: Life Cycle Assessment of a Design-for-Disassembly Building. Sustainable Production and Consumption. Volume 37, May.
  • Fiona Greer, F. & Horvath, A. (2023). Modular Construction’s Capacity to Reduce Embodied Carbon Emissions in California’s Housing Sector. Building and Environment, Volume 240.

Share This