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Greenbuild 2010: Sound Materials Decisions Can offer Immediate Carbon Reductions

So far Greenbuild 2010 has been jam-packed with great sessions.  Today's pick: Reducing Embodied Carbon in the Built Environment.  While energy efficiency is agreed to be a top priority for carbon reductions, speakers at this session also emphasized the importance of addressing the embodied energy and carbon in buildings (particularly those buildings that use significant amounts of concrete, a very GHG-intense material).  The well made argument was based on the fact that we need to achieve radical GHG reductions within the next twenty years to hit target levels. By reducing embodied carbon in the buildings we are building today, we can make those reductions immediately while also benefiting from the reduced emissions during occupancy as a result of energy efficiencies.   The bottom line: embodied carbon reductions provide the benefit of immediate emissions reductions.

Sound material choices can cut carbon impact immediately.

The challenge: there aren't any really good or reliable data on embodied energy that offer enough granularity to make sound materials selection decisions (yes, there are some tools, but they each have problems).  To illustrate the importance of this issue, one presenter shared a case study of a commercial building project where they estimated embodied carbon and compared it to the estimated carbon emissions during building occupancy over the next 20 years (the period he defined as requiring dramatic GHG emissions reductions).  The results indicated that the embodied carbon in materials represented 20% of total emissions, and when the energy efficiency of the building was improved, the embodied carbon accounted for 50% (simply because the energy use emissions were decreased).  

These are compelling numbers and are comparable to a peer-reviewed Life Cycle Assessment (LCA) study released by Earth Advantage Institute and Oregon Department of Environmental Quality that I presented at an earlier Greenbuild session today.  Our study took a slightly different approach as we were comparing the impacts of different building techniques over the 70-year life of a residential home.  We found that for a standard home built to code, the life cycle GHG impacts of materials accounted for 16% of total impacts (the lion's share being represented by energy use impacts during occupancy).  However, when considering the effect of building a home to much higher energy efficiency standards, we found that the materials impacts (embodied carbon) accounted for 30%.  

The bottom line: as we build to higher energy efficiency standards in both the commercial and residential sectors, we need to also invest energy (as in brain power) in developing accurate tools to enable the best material selection decisions possible.  They matter immensely, and we have to get them right.

About the Author

Indigo Teiwes

Indigo is the Director of the Carbon Advantage Program at Earth Advantage Institute. Indigo has over ten years of strategic analysis, advisory, and program management experience. Her work includes investment opportunity analysis related to environmental sustainability and climate change issues, carbon footprint/emissions inventories, energy efficiency and renewable energy company analyses, and designing and developing tools for evaluating carbon offset providers who sell verified emissions reductions (VERs). Relevant projects include two white papers, Carbon Offset Provider Evaluation Matrix and Ecological Limits and Economics: Investing in a Full World, as well as a carbon mitigation plan that received a City of Portland BEST Award. Prior to joining Earth Advantage Institute, Teiwes directed the Sustainability Research Program at Portfolio 21, a global mutual fund identifying and investing in companies positioned to outperform their competitors due to their proactive approach to sustainability issues. During her tenure with Portfolio 21 the fund not only outperformed its benchmark (the MSCI World Equity Index), but also grew assets under management from less than two million to over 273 million dollars. Teiwes has an MBA in sustainable business from Bainbridge Graduate Institute, and a B.S. with a double-major in business administration (concentration in management) and environmental studies from the University of Oregon (Summa Cum Laude).