Sean Brennan

Senior Associate

Sean Brennan, PE, is an accomplished engineer, researcher, and passionate about decarbonizing the energy industry influencer. He has two decades of experience in the building design and utility sectors. Sean leads a team of engineers and scientists in projects that pioneer clean energy technologies, forecast electrification impacts and grid enhancements, and map out decarbonization pathways.

Prior to joining Cadmus, he served as the Director of Research at Urban Green Council, an environmental nonprofit, producing data-driven building science research that shaped climate and energy policies in New York City, including the Building Emissions Law (Local Law 97 of 2019) and the All-electric Building Law (Local Law 154 of 2021).

Sean’s diverse experience includes consulting roles at Pacific Gas & Electric and Sempra utilities in California, research collaborations with the Natural Resources Defense Council and the U.S. Green Building Council, and project management with Integral Group. He also played a vital role in Sefaira, a sustainability software startup, helping develop its product and expand its client base in the architectural and engineering sectors. Sean’s portfolio spans numerous commercial, educational, and specialty projects across North America, optimizing envelope and HVAC designs for enhanced efficiency.

Sean holds a bachelor’s degree in mechanical engineering from Carnegie Mellon University and a master’s degree in civil engineering from Stanford University. He is a licensed mechanical engineer specializing in building design and analysis.

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