Greenhouse 100 Polluters Index (2016 Report, Based on 2014 Data) Rank Parent corporation or entity 2014 Emissions(CO2 equivalent metric tons) Percentage of total U.S. greenhouse gas emissions from all sources * Industrial Sectors 1 Duke Energy 122,474,576 1.84% Power Plants, Other, Petroleum and Natural Gas Systems, Waste 2 American Electric Power 121,098,420 1.81% Power Plants, Other 3 Southern Co. 108,671,229 1.63% Power Plants, Other 4 NRG Energy Inc. 100,224,829 1.50% Power Plants, Other 5 Berkshir...