PUMPED STORAGE TUNNELS | INSIGHT
Left:
Cavern with equipment inside Racoon Mountain pumped storage plant
WHAT IS PUMPED STORAGE? Pumped storage hydropower is one of the oldest and most reliable forms of power storage. In fact, it’s been around for more than a hundred years. The first pumped storage hydropower project was developed in Switzerland in 1907, and United States (US) started bringing projects online in the 1930’s. Today, the International Hydropower Association (IHA) estimates that pumped storage hydropower projects can store up to 9000 gigawatt hours (GWh) of electricity worldwide. So, how does pumped storage work? Traditional hydroelectric projects use the pressure
of water flowing downstream to spin turbines and generate electricity. These kinds of projects take advantage of water and use the potential energy of its vertical drop to generate renewable energy. On the other hand, pumped storage projects add the
ability to pump water back uphill to be reused time and time again to generate electricity. It is a closed system where water is pumped up, released down, and pumped up again, repeatedly. Obviously, this method would not work in a traditional river system. What pumped storage projects rely on is elevation. Pumped storage projects utilize two reservoirs
close together with a significant elevation difference. These two reservoirs are connected by tunnels that pass through a powerhouse. The powerhouse contains reversible pump-turbines that can generate electricity while in turbine mode and store energy while in pump
mode. When there is excess electricity on the grid, water is pumped up for ‘storage’ in the upper reservoir. When electricity is needed, water is released back down, using the force of gravity to push water through the turbines to generate electricity. That water is then released back into the lower reservoir for later use. The powerhouses are typically an underground complex of caverns and waterways that are some of the largest in the world. Pumped storage can give us the ability to better
manage our grid. It has done so for generations, leveraging the excess energy from fossil fuel-based plants to pump water back up to the upper reservoir for use – energy that would have been lost regardless because we can’t simply turn a coal plant on and off each night. The benefits are clear, and we should be
implementing more pumped storage projects around the world. So, let’s look at what we need to do to drive more pumped storage projects forward to successful completion.
PUMPED STORAGE: KEY REQUIREMENTS Pumped storage projects are complex to say the least. They require significant planning and collaboration across a wide range of disciplines. They require very specific site characteristics. And they require additional infrastructure like roads, tunnels, and shafts to make the project viable. Let’s breakdown some of the key requirements for pumped storage projects:
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