36% neither actively track nor try to reduce embodied carbon on projects
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Time Value of Embodied Carbon
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Why concrete first?
After water it’s the most used substance in the world
billions of tons/yr worldwide
~1 ton concrete ~1 ton GHG (carbon)
5-10% of worldwide GHG emissions
On most projects it will be biggest source of embodied Carbon
Biden infrastructure plan will increase demand [and provide some funding]
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Why a non-binding resolution?��
Low awareness, little activity
Little EPD (environmental product declaration) data
There were products available, but nobody knew to ask.
Coming in July 2024, California will be first to have mandatory limits
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Sources of the Carbon in Concrete
Mix of sand, gravel, water, cement
Most comes from cement
Heating limestone to high temperatureby burning fossil fuels
Chemical reaction releases CO2
Good news: C can be reduced at little to no cost premium
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Reducing Carbon
Available today
Replacement of portion of cement with other binder materials
Emerging
Carbon capture, storage, use
Industry goal is zero Carbon or better by 2050
More efficient heating, transportation
Building design, life cycle analysis
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Some Examples
BU Center for Data Sciences; cut carbon in concrete by 12%
Arlington High School; six different mixes, cut carbon in concrete by 30%
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The Benefits
Help Brookline reduce its carbon footprint
Spread the word, spur municipalities and the industry to use more low carbon concrete and develop new techniques, and consider the effect of embodied carbon in buildings and other applications.
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Others Working on Low Carbon Concrete Regs
2021:
Some states, eg NY, NJ, CA, OR
Marin County, CA
2024:
MA
Boston, Cambridge, Newton, Brookline
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Town Meeting Result
Unanimous support from Brookline’s Select Board, Advisory Committee, School Committee, Green Caucus, Climate Action Brookline
DPW pilot project
WA 18 passed unanimously
at Town Meeting November 18, 2021
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Current Status in Brookline
DPW
Sidewalk pilot at Town Hall
has held up well; ~15% less carbon; low material cost increment; established that local concrete suppliers are familiar with the product and can provide when needed.
Highway Dept feedback
11 test pours—small (~6-11 tons); integrity good to date,
Workability an issue—takes longer than their typical mix;
Pretty strict requirements regarding appearance (horizontal, visible vs vertical, enclosed)
The team will continue to explore options and test alternatives, but not yet ready to standardize on low carbon concrete —need to reduce time and gain confidence in the final appearance.
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Current Status in Brookline (cont’d)
Building dept:
So far no commitments to require low C use anywhere, but supportive;
Next possibilities are Pierce School and firehouse renovation.
Planning to get embodied carbon considerationsin the revision of our climate action plan
Rezoning in response to MBTA Communities Act may provide opportunity to develop new design review standards
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Evolving Market
Lots of EPDs (environmental product declaration)
Federal efforts—lead by example
IRA over $2 Billion in funding for construction materials and products with “substantially lower levels of embodied greenhouse gas emissions” for the General Services Administration and the Federal Highway Administration Administration.
Need to consider systemic impacts, eg EVs have high embodied carbon but enable more efficient transportation; don’t lose sight of the end-goal
and then Incorporate embodied carbon considerations into our climate action plan revision—getting started (technology/material neutral to encourage innovation)
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Next Steps - 2
Deconstruction vs demolition--under active consideration