By Barry Cassell
Moriah Hydro Corp. on Oct. 4 filed with the Federal Energy Regulatory Commission a draft license application on the 260-MW Mineville Pumped Storage Project, which would use a shut underground mine located in the Town of Moriah, N.Y.
The existing mine comprises the interconnected Old Bed, New Bed, Bonanza open pit, and Harmony mines previously developed by Republic Steel and its predecessors. Old Bed and Harmony are connected to each other at several elevations by horizontal tunnels (crosscuts). The Bonanza open pit mine connects to Old Bed by a crosscut. New Bed connects to Harmony at one location through an excavated ore pocket and will be isolated from Harmony by a concrete isolation bulkhead. New Bed will not be used as part of the project.
The upper and lower reservoirs for the pumped storage project will be completely contained within the existing mine cavities. A concrete hydraulic bulkhead will separate and contain the upper reservoir within the existing mine.
The powerhouse will be constructed underground, adjacent to the mine, approximately 2,050 feet below the upper reservoir. The powerhouse will be accessible through the main shaft from an entry building at the surface.
The main shaft will be constructed adjacent to the mine, extending 2,955 feet from the surface down to the powerhouse. The main shaft, approximately 25 feet in diameter, will consist of a hoistway and elevator located directly above the powerhouse chamber.
The high and low-pressure penstocks, each 15 feet in diameter, will be constructed from steel and embedded beneath the powerhouse floor. An electrical tunnel will connect the electrical equipment chamber to a new 115-kV substation constructed adjacent to an existing 115-kV transmission line located approximately one horizontal mile from the underground powerhouse.
The project will use 20 pump-turbine/generator power trains. Each power train will consist of five reversible pump-turbines connected in series. Each reversible pump/turbine will have three stages and will be directly coupled to a synchronous motor/generator rated at 2,600 kW, 3,450 HP in turbine mode, and 2,790 HP in pump mode. Each parallel train will have a capacity of 13,000 kW. The total installed capacity of the powerhouse with all power trains operating in parallel will be 260,000 kW.
The project will be operated in a generation or storage mode depending on system demands.
“Plant operation will be fully automatic,” the application noted. “The proposed pumped storage project will likely generate during periods of high demand and recharge during periods of low demand. A pumped storage project is not susceptible to seasonal flow variations; therefore, operation during adverse, mean, and high water years is not applicable. Assuming a maximum plant generation schedule of 10 hours per day, the plant would be capable of providing 737,600,000 kWh annually. The estimated average annual plant output is 421,000,000 kWh. The estimated annual capacity factor is 23 percent.”
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