The Requirements for an Ideal Location for a Pumped Hydroelectric $500 \mathrm {~m}$

The requirements for an ideal location for a pumped hydroelectric storage facility are not the same as those for a hydroelectric generating station. For pumped storage, a location for a reservoir at an elevation above a supply of water is required. It is convenient if the location is also compatible with the production of alternative energy facilities such as solar or wind, as these benefit greatly from the ability to store energy. Cape Breton Island in Nova Scotia, Canada is an ideal location to consider the possibility of combining wind power (as the region has good wind resources) with pumped hydroelectric storage (as the region consists of a plateau at an elevation of about $500 \mathrm {~m}$ above the Atlantic Ocean). Specify the design of a wind/pumped hydroelectric system on Cape Breton Island that could supply the electric needs of a population of 100,000 . Consider a simple example where the per-capita electric use is a constant $0.7 \mathrm {~kW}$ and the wind velocity is constant during the day (12 hours), providing $55 \%$ of the rated turbine capacity, and zero at night. A fraction of the electricity generated during the day is used to pump sea water into a reservoir at an average elevation of $500 \mathrm {~m}$ , and this is used to provide electricity when there is no wind. Suggest design criteria for such a system, including at least the following:
- The number and capacity of wind turbines
- The fraction of wind turbine output to be used to pump water to the reservoir
- Capacity of hydroelectric turbines
- Hydroelectric turbine and pumping efficiency
- Size of the storage reservoir