The use of submersible pump-turbines and motor-generators in pumped storage hydropower (PSH) can improve efficiency in several ways:
Improvements by Submersible Pump-Turbines
- Reversible Operation: Pump-turbines used in PSH systems can operate in both directions—pumping water to an upper reservoir during off-peak periods and generating electricity when the water is released. Submersible designs allow for more compact installations and potentially easier maintenance, which can enhance overall system efficiency.
- Optimized Flow Control: Submersible pumps can provide better flow control by being placed directly in the water flow path. This can help minimize energy losses and optimize the flow rates during both pumping and generating cycles.
Improvements by Motor-Generators
- Efficient Energy Conversion: Motor-generators used in PSH systems convert electrical energy into mechanical energy for pumping and vice versa for generating. High-efficiency motors and generators can reduce energy losses during these conversions, improving the overall round-trip efficiency of the system.
- Variable Speed Operation: Modern motor-generators can operate at variable speeds, allowing the system to optimize its performance under different operating conditions. This flexibility enhances efficiency by ensuring that the system operates at its best possible speed at all times, which can significantly reduce energy consumption during pumping and increase output during generation.
- Reduced Maintenance: By integrating motors and generators into compact, submersible units, maintenance access can be improved, reducing downtime and ensuring that equipment operates at optimal levels more consistently.
Overall Efficiency Gain
The round-trip efficiency of PSH systems, which includes both the pumping and generating cycles, typically ranges from 70% to 80%. Improvements in pump-turbine design and motor-generator technology can potentially push this efficiency range higher, making PSH a more cost-effective and environmentally friendly form of grid-scale energy storage. Additionally, these advancements can help reduce operational costs and enhance the overall reliability of PSH systems.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-does-the-use-of-submersible-pump-turbines-and-motor-generators-improve-the-efficiency-of-pumped-storage-hydropower/
