Cobble Mountain Unit 3 Valve Replacements

Description: Cobble Mountain Hydroelectric Station Unit 3 uses two large butterfly isolation valves, an electric motor operated Upper Isolation Valve and a hydraulically controlled Lower Isolation Valve—for penstock and turbine shutoff. Both valves, original to the 1930s, are corroded, leak excessively, and have surpassed their design life, prompting a modernization project to replace them and the associated components with modern equipment rated for a 50-year lifespan. The new valves will be custom fabricated to fit the same footprint as the existing valves, eliminating the need for penstock modifications. The procurement specifications include an alternative bid option to obtain cost and schedule information for also replacing Unit 1 valves, identical to the Unit 3 scope.