New York Power Authority (NYPA) is planning a major overhaul of the Niagara Power Project's Lewiston Pump Generating Plant (LPGP) to extend the life of the hydroelectric project's auxiliary facility and enhance its performance.
The Power Authority Board of Trustees approved a $460m Life Extension and Modernization (LEM) program for the LPGP facility, which operates during periods of peak power demand in supplementing the electricity output of the Robert Moses Niagara Power Plant, the Niagara Project’s main generating facility.
The trustees also authorized initial capital expenditures of $131m for the upgrade and the award of a 10-year contract to Hitachi Power Systems America of Basking Ridge, New Jersey, which was the lowest-cost qualified bidder for replacing and modifying major components of LPGP’s pump-turbine generators.
In 2006, NYPA completed a $24m maintenance program at LPGP in the same year that it finished a $298m, 15-year program to upgrade the Robert Moses Niagara Power Plant, where the Power Authority replaced turbines and retrofitted other components of all 13 generating units.
The LEM at the pump generating plant will be an undertaking of similar scope, for overhaul of the plant’s 12 pump turbine generator units, which date back to 1961, when the Niagara project was first placed into service. The work will include replacing the turbine runners, the rotating portion of the equipment. The runners, which typically weigh about 75 tons, transfer energy from the water flow to the generators.
The upgrade will begin in late 2012 under a schedule providing for the overhaul of a turbine generator unit every eight to nine months, with the final unit completed in 2020. The phase-in schedule provides for 11 of the 12 LPGP units to be available for operation during the LEM so that NYPA can meet its commitments to its customers.
Pumped-storage facilities like the LPGP store water as potential energy during off-peak hours for later use when demand is higher. The principal benefits are retiming of generation and providing the ability to quickly respond to changes in customer demand.
At night or on weekends, when electricity demand is low, LPGP’s reversible pump turbine generating units operate as pumps, transporting water from the Niagara project’s forebay up to the Lewiston plant’s 22-billion-gallon upper reservoir, which is approximately 70ft to 120ft higher in elevation. Surplus electricity from the Moses plant is used to power the pumps to push water into the Lewiston Reservoir during the off-peak times.
During the daytime, when electricity use peaks, the pumps are reversed and become generators similar to the Moses plant. In this way, Niagara River water can be used to produce electricity twice, with the same water flowing through the Lewiston generators and then the generating units at the Moses plant, which also capture the potential energy of the water diverted from the river in real-time. Together, LPGP and the Moses plant combine for a net dependable capability of 2,441MW.
The Power Authority is also currently conducting a LEM program at another hydroelectric project, the St Lawrence-Franklin D Roosevelt Power Project in Massena. That initiative is more than three-quarters complete and scheduled to be finished by 2013.