Monday, February 22, 2016

Total Carbon Study

by Larry Strain, FAIA, LEED AP

Entrance to DPR San Francisco Office, 945 Front Street. Photo courtesy of DPR Construction.

Siegel & Strain Architects, in collaboration with Integral Group: Deep Green Engineering, recently completed the Total Carbon Study of the DPR San Francisco Office Building. The project converted an existing, two story office building in San Francisco into a net positive building.

Specifically, this study:
  • Signals the need for changes in climate action policy that prioritize deconstruction and reuse over demolition. 
  • Quantifies saved/avoided carbon attributed to retrofitting an existing building compared to building a new similar structure. 
  • Demonstrates nearly 70% reduction in the embodied carbon associated with building material supply chain between a new construction and significantly reused existing building structure. 
  • Quantifies the saved/avoided carbon from converting an average, two story office building into a net positive building. Net positive buildings generate more energy than they consume on an annual basis.

    We have just a few decades to stabilize and then phase out greenhouse gas (GHG) emissions to avoid irreversible climate change. Carbon reduction strategies need to be evaluated on their reduction potential in the near term.There is a time value to carbon savings that we must take into account. The current "gold standard" for reducing emissions from buildings is to build new, net zero energy buildings — focusing on eliminating emissions associated with the operations phase. While this is an important strategy to reduce GHG emissions in the built environment, it does not address the two other major sources of building emissions from:
    • Embodied, upstream supply chain from building materials, and 
    • Operating emissions from existing buildings.

    Total Carbon (MTons CO2e) 50 year life comparison of Traditional Code-Compliant New Construction Office Building vs. the DPR San Francisco Net Positive Existing Building Retrofit Office.

    The Total Carbon Study makes the case for maximum reuse, coupled with deep green energy retrofits (net positive when conditions allow) as an effective strategy to produce the maximum amount of carbon savings in the shortest possible time.

    To read the entire Total Carbon Study, download this PDF