Mr. Sigmon is currently in his 50th year of engineering involving work on the mechanical design and operational support of hydroelectric, nuclear, and fossil electric generating facilities; 42 of those years dedicated solely to hydro. He has participated in the upgrade of hydraulic turbines and pump-turbines as well as installation of new hydraulic turbines, both domestically and internationally, ranging in size from 400 kW to 510 MW at over 30 hydroelectric stations (over 80 units total). The turbine and pump-turbine upgrades have included replacement of runners including model testing in some cases, machine design improvements, complete refurbishment as well as modifications or new components including turbine discharge aeration. He has also participated in various station auxiliary mechanical system replacements and design upgrades.

Mr. Sigmon's pumped storage experience includes extensive engineering associated with the upgrade and rehabilitation of major pumped storage stations for Ameren Missouri, Duke Energy and Xcel. He has also participated in feasibility/conceptual design studies for a number of pumped storage stations. These activities range from participation in sizing of the units through layout of the powerhouse, to optimization of the water conveyance system including performance of stability and hydraulic transient analyses.