GREEN FOOTSTEP: CALCULATIONS AND DATA SOURCES

The document explains the methodology of the Green Footstep tool, which calculates the net carbon flow of building projects by analyzing site development, construction, and operation. It defines carbon neutrality as achieving a net carbon storage level equal to or greater than the site's native state. The paper provides specific formulas for calculating native site carbon storage, emissions from site development, and operational emissions. For construction emissions, it details an Economic Input-Output Life Cycle Assessment (EIO LCA) approach based on 1997 US economic data, offering coefficients for residential, multifamily, manufacturing/industrial, and commercial/institutional sectors. It also includes a historical validation comparing 1997 energy intensity coefficients with 1967 data, noting a general decrease in energy intensity for most sectors except commercial and institutional buildings.

• Green Footstep defines a building project as "carbon neutral" if, by the end of the analysis period, the net amount of carbon stored on the site is equal to or greater than the amount stored in its native state.
• The tool calculates net carbon flow by accounting for three primary sources: site development (removal or addition of vegetation), construction (raw material extraction, manufacture, transport, and assembly), and operation (Scope 1 and 2 emissions from electricity, natural gas, and other fuels, with optional Scope 3 emissions like commuting).
• Native site carbon storage is calculated by multiplying the site area by the carbon intensity of the native ecological zone, using IPCC data for forests and grasslands.
• For construction emissions, the tool provides an EIO LCA option based on 1997 US National Purchaser Price model data, which assigns carbon intensity per US dollar of construction activity across four sectors: 1-unit Residential, Multifamily, Manufacturing and industrial buildings, and Commercial and institutional buildings.
• The document derives carbon intensity coefficients per square foot for new construction based on 1997 data, finding that Commercial and institutional buildings have the highest carbon intensity at 120 kg CO2e/ft2, followed by Manufacturing and industrial buildings at 49 kg CO2e/ft2, 1-unit Residential at 45 kg CO2e/ft2, and Multifamily at 42 kg CO2e/ft2.
• A historical comparison between 1967 and 1997 data indicates that energy intensity in building construction decreased by approximately 30% for 1-unit residential, multifamily, and manufacturing/industrial sectors, while it increased by 15% for commercial and institutional buildings.

APA

Bendewald, M., & Olgyay, V. (2011). GREEN FOOTSTEP: CALCULATIONS AND DATA SOURCES. RMI. https://rmi.org/app/uploads/2017/05/RMI_Document_Repository_Public-Reprts_2011-11_GreenFootstep.pdf

Chicago

Bendewald, Michael, and Victor Olgyay. GREEN FOOTSTEP: CALCULATIONS AND DATA SOURCES. RMI, 2011. https://rmi.org/app/uploads/2017/05/RMI_Document_Repository_Public-Reprts_2011-11_GreenFootstep.pdf.

Wikipedia

{{cite report |last1=Bendewald |first1=Michael |last2=Olgyay |first2=Victor |title=GREEN FOOTSTEP: CALCULATIONS AND DATA SOURCES |publisher=RMI |date=July 2011 |url=https://rmi.org/app/uploads/2017/05/RMI_Document_Repository_Public-Reprts_2011-11_GreenFootstep.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{bendewald2011green, author = {Bendewald, Michael and Olgyay, Victor}, title = {{GREEN FOOTSTEP: CALCULATIONS AND DATA SOURCES}}, institution = {RMI}, year = {2011}, month = jul, url = {https://rmi.org/app/uploads/2017/05/RMI_Document_Repository_Public-Reprts_2011-11_GreenFootstep.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }