Pumped-storage hydro power is just a giant battery!
Using elevated water reservoirs to store energy. Source here.
How I learned about efficient energy storage while on random hiking trip near Georgetown, Colorado.
This is a story about taking what you already know about batteries and how to think more broadly about energy storage at scale. If you’re like me, you probably learned early on how to identify the ubiquitous AA or AAA batteries and how different they are from the 9-volt battery that can give your tongue a little shock and apparently is now only ever used in smoke detectors.
At several points in your life, you probably also tried to get excited about replacing these alkaline (non-rechargeable) batteries with “cooler” rechargeable varieties, maybe for your early Game Boy or TV remote. No doubt you were motivated in these efforts by a well-meaning and determined attempt to save money, reduce waste and protect the planet…?
Over the years, we have all become more familiar with batteries of all shapes and sizes. Think about those giant, heavy batteries used for camping lanterns or those small disc-shaped batteries for portable electronic toys or cheap watches.
We may have also needed to brush up on the various battery technologies like when we started swapping out nickel metal hydride (NiMH) or nickel cadmium (NiCad) rechargeable batteries for the apparent winner, lithium ion (Li-ion) which is used in every smartphone, laptop and now in electric vehicles or EVs.
Source here if you need it.
Or when we learned (the hard way) that our larger car batteries, of the lead acid variety, also need to be recharged regularly!
Speaking of road trips, this story took place when I was visiting a friend in Colorado and decided to take a hike near one of the infamous “passes” that lure hikers up into the mountains.
It was on the way back down Guanella Pass that I saw the Cabin Creek plant and stopped at various points to take a closer look. What I learned from the really informative roadside signs along the route was that Georgetown Colorado is the site of one of the earliest hydroelectric plants - an energy facility that produces electricity from water-turned turbines. This is quite straightforward because the steep terrain of these mountains and the steady supply of water from the melting snow and falling rain means a fairly predictable energy source for this area.
I wasn’t able to visit the Georgetown Energy Museum as it had cut back to summertime hours only, but the town is certainly proud of its place in the energy timeline of the US. The Museum is actually situated in a “fully functioning and operational Hydroelectric generating plant” owned by Xcel Energy and has been running since 1900. This is already kinda cool but the better part (for burgeoning energy geeks like me at least) is that Cabin Creek is also home to a pumped-storage hydropower installation.
This sign does a much better job of explaining all this and even shows an aerial view of the two reservoirs that combine to create this massive battery.
There are informational signs like this for the Cabin Creek facility along the pass.
What I learned on this trip and then from additional reading here and here for example, is that pumped-storage hydropower is one of the most efficient, “rechargeable” batteries we have ever created.
It works like this: when Georgetown needs energy, the operators release water from the upper full reservoir to flow down to turn the turbines and generate electricity. The water collects in the lower reservoir and when town’s power demand goes down and there is excess electricity available, they reverse the turbines and pump the water back up to the upper reservoir!
I must admit, it took me a minute to relate this to the rechargeable battery packs I carry around to boost my draining iPhone after a long day of use. But these batteries are very similar. They both are capable of holding a “charge” to be used later to provide power on demand and both can be recharged when there is excess power available. One uses an AC outlet (or often my solar panels when I’m off grid) and the other uses excess power from the larger grid.
What is impressive about the pumped-storage hydro battery though is how it doesn’t suffer from the common challenges associated with our portable rechargeable batteries. For example:
Memory - Some batteries have memory issues where if they are not discharged appropriately, they begin to lose their ability to store power. Nickel-cadmium rechargeable batteries are prone to this memory problem for example. The pumped-storage battery does not suffer from memory issues as the upper reservoir will not degrade over time (assuming its foundations stay intact).
Shelf Life - NiCad and Li-ion batteries can be stored fully- or mostly charged for 2-5 years on average but will ultimately lose their reserves at some point. The dual-reservoir system does not really have a shelf-life problem as water, a clean and renewable natural resource, is plentiful in areas like this.
Cycles - Our current portable battery technologies also struggle to continue to work after a certain number of charge/discharge cycles. Even if they are maintained properly, our familiar rechargeable batteries typically only last hundreds of cycles before they’re done. The Cabin Creek facility and others like it can clearly go on for decades or longer!
I’ve only mentioned a few of the reasons why you should be impressed with the efficiency of this massive battery. And while I’m sure there was some damage to the natural landscape to build this installation (more on that controversial topic I’m sure when I visit Hetch Hetchy in the weeks ahead), it has been operating as a clean, renewable source of electricity generation and as a giant, efficient energy storage solution.
More on both of those topics in the posts to come.
Special thanks to my good friend Eric in Golden Colorado for helping me appreciate this topic and for recommending the Nissan Leaf - also coming soon!