Angat Hydroelectric Power Plant turbine repairs won’t affect Metro Manila’s water supply

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Posted on on August 6, 2022

The rehabilitation of Auxiliary Turbine Unit No. 2 (AU#2) at the Angat Hydroelectric Power Plant (AHEPP) is scheduled to begin on 8 August 2022 to 8 April 2023.

Water allocation from Angat is transmitted through Auxiliary Turbines 1 to 5 and By-pass Nos. 1 and 2.  With regular use and exposure to a variety of weather conditions, the turbine-generator systems need to be rehabilitated to ensure they remain in working order for the longer term and do not present any danger to third parties.  The 244 man-days work involves complete dismantling and replacement of old systems; assembly and installation of new and automated systems.

The Angat Dam Operations and Management Inter-agency Technical Working Group (composed of the MWSS and the Common Purpose Facilities-Manila Water and Maynilad, the National Water Resources Board [NWRB], the National Power Corporation [NPC], and the National Irrigation Authority [NIA]) finally agreed to the Angat Hydropower Corporation (AHC) shutting down of the AU#2 only after it was satisfied that the impact and risk had been substantially mitigated.  The MWSS assisted the Common Purpose Facilities group with activities such as expert safety evaluations, underwater inspections, and testing the control valves of the Angat Dam Low Level Outlet (LLO) to rule out any electromechanical failures and identify additional mitigation areas to prevent threats to the water supply of Metro Manila.

MWSS Administrator Leonor Cleofas requested that the AHC and the CPF increase the number of workers (divers, fabricators, and engineers) monitoring the workplace and that all hands be on deck in the event of an emergency at the Angat Dam. 

She wishes to assure the public that while normal dam operations will be affected by the repair, the risk to water supply is low as the dam will maintain its ability to release water through the by-passes of the auxiliary turbines and the operation of the Low-Level outlet.  An alarm system that alerts operators to sudden decreases in flow detected by stream gauges will prevent domestic allocation from being reduced. The allocation of 48 cubic meters per second (CMS) to MWSS Concessionaires is guaranteed, and there will be no to minimal disruption in water supply operations.

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