Marshall is an international expert in carbon neutrality planning and modelling, energy analytics, and building performance standards, with over a dozen years of experience working in the for-profit, non-profit, and government sectors. He has advised over 20 cities and 15 institutions across North American on advanced energy and climate planning—including developing energy & emissions models, managing complex public engagement processes, and developing numerous ground-breaking policies. Prior to joining Introba, he worked for the District of Columbia Department of Energy & Environment and the Institute for Market Transformation. Marshall also currently serves as Co-Chair of the DC Building Energy Performance Standards Task Force and Vice-Chair of the DC Sustainable Energy Utility Advisory Board.