Author(s): Chase Christensen, Najilah Jones, Ariel Jude Soliva, Gabriel Thompson
Mentor(s): Mohamed Askar, Jorge Servert, Guy Thompson
Institution SUU
Hydropower with reservoirs is the only form of renewable energy storage that is well-developed and in wide commercial use today. Pumped storage hydropower uses the potential energy in water to produce electricity in turbine mode. It is used to pump water to a higher elevation to store energy as potential energy in water. A pumped storage hydropower plant is attached to an upper reservoir and a lower reservoir by a conduit system consisting of a headrace tunnel and pressure shaft, draft tube, and tailrace tunnel, in the same way as in conventional hydropower. The main purpose of PSH is to allow efficient baseload generation by covering periods of peak demand and absorbing energy during hours of low demand, in addition to providing ancillary services, such as black start capability and stabilization of the network frequency and voltage level. The design of PSH is based on more starts and stops and alternating electricity production than conventional hydropower plants. Therefore, it is essential to ensure the safe, dynamic behavior of the whole system, including waterways, turbine/ pump, and generator. The dynamic behavior is connected to the conduit system design and the plant's performance characteristics. On the other hand, there is a demand for a machine with stable operation at low and high loads (low and high production or low and high flow). A reversible pump turbine compromises between an optimal pump and an optimal turbine. The design challenge is to achieve a stable pump and an efficient turbine at different loads. An improved prototype was developed using a single vessel made of carbon fiber, a reversible pump-turbine and motor generator, as well as a spray cooling/heating system. The smaller size of the carbon fiber vessel in this research allowed for an energy storage prototype of 3 kWh. Finally, this study presents innovative construction methods, including new excavation techniques and modular dam construction methods, that could potentially reduce the cost and time required to construct new PSH projects.