This study summarizes a recent life-cycle net energy analysis (NEA) on a modern natural gas turbine power plant for comparison against DT fusion and conventional technologies (coal, fission, and wind). The NEA results are used as the basis for developing a life-cycle greenhouse gas (GHG) emission rate. The GHG emission rate for DT fusion is 9 metric tonnes of CO2 equivalent emitted per gigawatt electric hour produced (T/GWeh). This rate compares favorably against gas turbine (464 T/GWeh) and conventional coal (974 T/GWeh), and competitively against fission (15 T/GWeh) and wind (15 T/GWeh). The implications of this research for U.S. GHG mitigation are discussed. In evaluated scenarios, the installed nuclear and renewable capacity in the U.S. must quadruple by 2050 to maintain a Kyoto based emission target, with fusion and/or other renewable sources comprising 43-59% of U.S. capacity.