A hot gas valving system for a ground-based power generation system includes a gas flow conduit having a wall and defining a path for fluid flow and a butterfly valve located in the wall and transversely across the path for fluid flow. The butterfly valve includes a first raceway defined by an inner ring and an outer ring, a second raceway defined by an inner ring and an outer ring, a combination of ball bearings and roller bearings retained in each raceway, an axle rotatably mounted in the inner rings of each raceway and cooperably rotatable therewith, and a baffle mounted longitudinally along the axle and extending from the axle into the path of fluid flow. Upon rotation of the axle, the baffle restricts or permits fluid flow.