A list of Chicago’s highest-ranking LEED-certified projects through September 2020, based on USGBC data. : Last year, for the third year in a row, Chicago was the nation’s leader in energy-efficient office buildings according to the 2019 National Green Building Adoption Index published by CBRE Group Inc., Maastricht University and the University of Guelph. The report showed that 71.1 percent of commercial office space was green-certified in the metro, followed by San Francisco and Atlanta.