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Roger Clarke-Johnson

Roger Clarke-Johnson

Sales & Marketing Director, Mercury Governor Group
United States

Roger has 42 years of experience in Renewable Energy, including 36 years in hydroelectric governors, unit controls, and hydraulic systems. He possesses a thorough knowledge of the design and operation of mechanical, analog, and digital hydro governors. The arc of his career spans both small and large hydro governor companies: Digitek, Woodward, GE, American Governor, and Emerson. Since 1991 Roger has contributed to the body of knowledge of the hydropower community. He was on the ASME PTC-29 committee that last revised the Power Test Code used by the hydro industry to test governor performance. He currently serves on the IEEE 125 and 1207 working groups and serves as the co-chair of the ASME Hydropower Technical Committee (HTC). He is also active in hydro industry conferences, currently serving on the Hydrovision Abstract Selection Subcommittee. He regularly chairs roundtable panels and presents technical papers at domestic and international hydropower conferences.


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