What is Pumped Storage Hydro

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Pumped storage hydro is a simple energy generation and storage concept that can be utilized for many applications. The process involves pumping water from a lower body of water to an upper body of water to create stored energy for future use. When that energy is needed, the water is released and the pumps are reversed to allow the water to run through hydroelectric turbines generating energy. This reversible turbine concept is the simplest form of pumped storage.

What Is Pumped Storage Video

The economics of such process is to use inexpensive power generated during night time hours, when energy demand is at its lowest, to pump water to the upper water body and when electrical demand is high, during the day time hours, generate electricity. The ability to store energy and utilize it smartly allows more efficient use of the transmission grid, as it can be operated at a constant load rather than cycling up and down to meet demand.

Besides these basic applications of pumped storage hydro, this technology is a potential game-changer when it comes to supporting smart-grid transmission, changing electrical load, and energy storage. There is a constant effort by utility operators to keep electrical load in balance with electrical generation, as transmission lines are design to handle certain electrical loads. Therefore, balancing the load capacity of the lines with the needs of the system is important to minimize energy losses and operate a steady state system. The pumped storage hydro is a tool that will provide frequency and voltage support to keep the transmission system in balance.

With more and more variable generation sources, such as wind and solar power, becoming part of our nation’s energy portfolio, utility companies are finding it harder and harder to balance output and need. Basically, pumped storage hydro can be operated in a manner that will act as a “shock absorber” for the transmission grid, allowing the utility to generate power when there is not enough or to soak up and store excess power when there is too much.

These and other “ancillary” services can be provided by this technology. The key to the flexibility of the pumped storage hydro is the speed the facility can go from storing energy (pumping water into the upper water body) to the generation of energy (releasing water from the upper water body through the turbines to the lower body of water). The pure reversible turbine equipment requires stopping and reversing the water flow, this can take 20-30 minutes per cycle. The equipment is designed in a Quaternary configuration which will consist of 3 unit pairs.  Each pair will include a pump and a turbine with a dedicated 134 MW motor and a 134 MW generator respectively. Through the use of hydraulic short circuit, the unit can be generating power at the same time it is pumping water for storage. This provides for immediate response to changing energy needs.

The Gordon Butte Closed Loop Pumped Storage Hydro Project will be a versatile tool with all the attributes needed to quickly and reliably service the modern energy and transmission needs of the Northern Plains and Pacific Northwest.