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Putting Green Footstep to Use

RMI’s new calculator helps buildings reach net zero
By Molly Miller

Why would anyone need to know the amount of carbon storage inherent in a scrub ecosystem, and how would he or she find out such a thing?

Officials with the Archbold Biological Station (ABS), an ecological research facility in the Florida scrub, wanted to know exactly that when they decided to build their Lodge and Learning Center inside ABS’s 5,193 acre preserve.

The ecologically sensitive location of the Lodge and Learning Center, as well as ABS’s educational goals, inspired the project team to pursue carbon neutrality. RMI has been working with ABS to achieve this and other goals (such as LEED Platinum), and as part of that work, we were able to gather accurate data on carbon storage in the natural ecosystem.

How did we do it?

Green Footstep, RMI’s new carbon calculator, helps designers like Archbold’s reduce a building’s carbon emissions to zero, or as close to zero as the designer wants to go. Designers might even use the tool to design a building that actually achieves a net reduction in atmospheric carbon over the lifetime of the project. The tool is also useful to designers who are aiming for a given standard or target, such as a LEED rating or meeting the 2030 Challenge.

ABS was attracted to Green Footstep because of Green Footstep’s ability to quantify a design’s total carbon footprint as a result of site development (the change in carbon storage on the site due to the permanent removal or addition of vegetation), construction (the carbon emissions due to the raw material extraction, processing, onsite assembly, and transportation of building materials), and operation (the emissions due to the use of electricity, natural gas, and other fuels).

Green Footstep produces a graph of the emissions over several years.

In real time, a designer can adjust design “targets” for a building, changing the carbon footprint in relation to a baseline footprint. These design targets include the percentage of native vegetation on the site, the energy intensity of the building, and the amount of on site renewable energy. Green Footstep then produces a report describing how the carbon footprint of a project relates to global emissions reduction goals.

In the case of ABS, given the available roof area and budget for photovoltaic panels, load-reduction and mechanical system efficiency design targets were established to support the overall goal of carbon neutrality.

“Green Footstep empowers designers to have an impact on larger climate goals by showing how a building fits into the bigger picture and by encouraging a net zero building or a footprint positive building that results in a net decrease in carbon emissions,” said RMI Principal Architect Victor Olgyay. Olgyay created the first version of Green Footstep as an Excel file several years ago.

“The purpose of Green Footstep is to make it easier for designers to reduce the carbon emissions of their buildings,” added RMI Consultant Michael Bendewald, who developed Green Footstep as a full-fledged interactive web tool and made it available to eager designers who are beginning to try it on their projects.

“It’s really exciting to see a carbon foot-printing tool that’s interactive enough to be meaningful to architects early in the design process,” said architect Vikram Sami, of Lord, Aeck & Sargent Architecture. “I look forward to using this to facilitate carbon footprint dialogues on projects in our office.”

In addition to its functionality as a decision-making tool for designers like Sami, Green Footstep is also a great teaching tool. ABS also hopes to use Green Footstep to track and display the carbon lifecycle of the Lodge and Learning Center so visitors can compare it to carbon cycling in the scrub ecosystem. While still under design, the Archbold Lodge will offer accommodation to visiting researchers and students.

The Archbold Learning Center will include display, meeting, and office space in support of Archbold’s educational programs, which serve thousands of “K–12 through Gray” visitors annually. ABS hopes to use the building to raise local and regional awareness about climate change and the potential to address it through buildings.

Molly Miller is a Communications Specialist at RMI.

--Published October 2009

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