I worked in the snowmaking industry at ski resorts for more than a decade before getting into tech. Many ski resorts have a snowmaking reservoir at elevation and a pumping system to fill it (usually off peak) and then use gravity to actually feed the snowmaking guns (at least partially). Almost every snowmaking manager (that I talked to) has had the idea at some point to try some sort of pumped hydro offset, but I'm unaware of anyone who has actually tried it. It would be fairly small scale (reservoirs can be ~20 million gallons, usually less) but it would be interesting to see the economics of it because the infrastructure is already there (pumps, pipes, reservoirs, etc). The systems generally even sit unused for 7-8 months of the year.<p>I think some of the challenges are that while most resorts have a fairly massive pumping system, it's usually geared towards slowly filling the reservoir, with the rest direct feeding the snow guns. Not many places have the need to fill a 20 million gallon reservoir in a couple of days.<p>There's also the probability that the head pressure's wouldn't work out. Gravity feeding from an upper reservoir near the top of a large mountain can result in thousands of PSI at the bottom if not passed through a series of pressure relief valves. I'd imagine ideally you would have to build a generating station and a new catch reservoir at the perfect elevation because if you are pumping a lot higher than needed the efficiency is going to drop significantly.
This map provides an interesting overview over the electricity sources used in Europe:
<a href="https://app.electricitymaps.com/map" rel="nofollow">https://app.electricitymaps.com/map</a><p>I found it very interesting that pumped hydro is contributing a small but not insignificant portion of energy in a lot of countries, including Germany and France.
If people are interested in pumped hydro, Andrew Blakers et. al. from ANU have put together a global atlas of potential pumped hydro sites. They've got greenfield, brownfield, etc.<p><a href="https://re100.eng.anu.edu.au/pumped_hydro_atlas/" rel="nofollow">https://re100.eng.anu.edu.au/pumped_hydro_atlas/</a>
> Closed loop (off-river) pumped hydro storage has the smallest carbon emissions per unit of storage of all candidates for large-scale energy storage<p>Pumped-storage is a rather special approach as it feels almost like an extension of the natural water cycle.<p>Reducing the total footprint of the energy system (including all materials required for construction and ongoing maintenance) is an important part of the sustainability puzzle.<p>Ofcourse once you scale things to the gargantuan energy needs of modern civilization all sorts of minor "side-effects" may become important.
They can be hugely political. Snowy 2.0 has tripled in price and has been a political weapon between coal, gas and renewable energy investment. It has pretty torrid engineering troubles with tunnel boring. It will be late coming onstream. Some argue the money could be better spent on renewable, batteries and poles and wires.<p>The Queensland proposal at Kidston has become a pawn between two parties and probably won't go ahead as large, if at all.<p>Queensland's existing PHES was operated by the coal generator to earn it money in coal, not to reduce pricing in bids by undercutting. The government had to structurally separate it out to get better bidding outcomes noting that it co-owns the coal power station concerned and liked the revenue side as it is.<p>Pumped hydro can be very useful in "black start" events.
There are two <i>incredibly</i> common wrong assumptions made about pumped storage:<p>* It doesnt exist. Nobody says this outright of course but solar and wind skeptics often choose to "assume" that only more expensive lithium ion batteries can store power generated by solar or wind and "forget" about pumped hydro, being up to 3x cheaper.<p>* The geography for it is rare. The geography for hydroelectric dams which can also be used as pumped storage IS rare, because undammed dammable rivers are not common. However, for pumped storage it's not the case.<p>In both cases there are certain lobbies whom I think have a vested interest in perpetuating these false assumptions - the same way false assumptions about, say, wind turbines and bird deaths are perpetuated by people like Trump.
a thing I learned recently is that we are _already_ using hydroelectric power to balance out solar power - apparently with existing dams it's possible to dial down the flow in the daytime and dial it up at night. As more solar energy comes online, this becomes a natural consequence of energy markets
Pumped water is used quite a lot here in South Africa to help handle peak load in the national grid. It's probably going to continue to play a huge role as we transition to more solar.
I'll never forget the opportunity I had to visit the Helms Pumped Storage Plant. Driving directly into the side of the mountain and emerging into the generation facility was incredible. The shear size of the generators, the enormity piping, and the massive hunk of metal that are the turbine drives shafts left me reeling.<p>Each part is large beyond belief and the fact that it's not possible to view it in one piece only adds to the scale. Simply an feat of engineering.
NREL - National Renewable Energy Lab - interactive Pumped storage hydropower visualizer:
<a href="https://maps.nrel.gov/psh" rel="nofollow">https://maps.nrel.gov/psh</a><p>"Provides an effective way to view the national closed-loop Pumped Storage Hydropower (PSH) resource assessment and identify potential PSH sites while considering a wide array of possible technical and environmental specifications."
A few years ago there was a slew of articles about storing energy by lifting and stacking heavy blocks of concrete.<p>I have no idea how efficient those designs are compared to hydro storage but I imagine they solve a problem for regions where there is no suitable site for the water reservoir.<p>Haven't seen that concept in the news recently, maybe it didn't pan out?<p><a href="https://spectrum.ieee.org/gravity-energy-storage-will-show-its-potential-in-2021" rel="nofollow">https://spectrum.ieee.org/gravity-energy-storage-will-show-i...</a><p><a href="https://www.wired.com/story/energy-vault-gravity-storage/" rel="nofollow">https://www.wired.com/story/energy-vault-gravity-storage/</a>
Is there a limit to the height (fall) needed to produce power? In other words does a drop of 500 feet produce the same power as a drop of 1000 feet? I assume there's a limit on how fast a turbine can spin and also a terminal velocity for water falling through a tunnel? Not sure if I am asking this right but for wind turbines for example 60 mph wind and 40 mph wind are the same, there's a limit on how quick those blades can spin.
Easy where there is a lot of mountains (japan, Austria, France), harder in flat countries.<p>Interesting part of the article on electrolysis to use the lighter than air H2 instead of pumping water up. Smells a lot like over-engineering but seems fun !
Here is an insane video showing how difficult it can be to dig pumped storage tunnels: <a href="https://youtu.be/6AV2NcyX7pk" rel="nofollow">https://youtu.be/6AV2NcyX7pk</a>