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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 a

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. 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. 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.

pbmonster 2y ago
> 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. I don't think that's a concern. There's hydro plants with more than 6000' of head, leading to almost 3000 psi of pressure at the turbine and an exit velocity of the water jet of over 600 ft/s. From an engineering standpoint its totally manageable, and results in a highly efficient turbine. > 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. Good news is that adding another pipe with its own pump/generator is relatively cheap. Bad news is that 20 million gallons is a relatively small reservoir for pumped hydro, and increasing that is expensive. Still, seems like an easy and fast way to get some additional capacity online, especially in cases where a couple of megawatt of new solar get build in the vicinity of that damn...
- gorbypark 2y ago
  The only problem of 3000 PSI is 99% of the snowmaking pipelines out there would instantly blow up at that pressure :) You would also need to have PRVs anyways, because anything above about 700psi (900 if you are pushing it) is unusable/unsafe to use by the actual snowmakers and equipment. You also run soft 2" "fire" hose from a hydrant to a gun, and those are not rated for those pressures and the nozzles of the snow guns would wear out super quick as well (and the internal plumbing of the gun would probably blow up too). You'd generally have a max of about 900 PSI and ideally much lower as most of these pipes are relatively old, have no maintenance (until they blow up and a quick patch is made) and were welded up by "Bob the maintenance guy"! I suppose you could design a brand new system to be capable of such pressures when run in "generation" mode and still have some PRVs to keep it at a usable pressure during snowmaking operations.
  - Danieru 2y ago
    If you pump up the hill, say to 3000PSI, then waste pressure on the way down: you lose said wasted energy. Pumped Hydrogen Storage requires maintaining full pressure across the entire pipe. Which should be reasonable: the "fill up" pipe already needs to go from the bottom to top at full pressure. Reversing the flow should be enough. The issue would be if the fill method was staged pumps.
- lostlogin 2y ago
  > an exit velocity of the water jet of over 600 ft/s. I’m completely unfamiliar with any of this stuff so please keep this in mind… If that’s the exit velocity, shouldn’t the turbine it’s spinning be geared to give a bit more resistance? Or is that the velocity of the water if its path is unimpeded?
  - Danieru 2y ago
    Exit velocity is the nozzle exit speed. The water exists the nozzle and hits the turbine. With that said, turbine efficiency is not strictly based on resistance. Rather it is about extraction of energy. In a few designs it looks like resistance, others it is about redirection: https://www.energy.gov/eere/water/types-hydropower-turbines https://www.energy.gov/eere/water/types-hydropower-turbines
phreeza 2y ago
Flims in Switzerland has a kind of hybrid scheme planned where they use a reservoir for both snowmaking and hydroelectricity. https://www.wasserweltenflims.ch/wasser-in-flims/mehrzweckspeicher/ https://www.wasserweltenflims.ch/wasser-in-flims/mehrzwecksp...
- maxerickson 2y ago
  To what extent does it end up being "allow withdrawals for snowmaking" vs the thing being intended for snowmaking?
  - phreeza 2y ago
    Well it's an enlargement of an existing snowmaking reservoir so I suspect it is the the latter. Probably part of a strategy to make the resort look eco-friendly.
    - gorbypark 2y ago
      Using google translate, it shows they are planning on upgrading the reservoir to 1 million cubic meters, which is about 264 million gallons from ~58 and that it will fill 3 times a year naturally, 4 times with pumps. 1/3 will be used to just keep the river flowing down the mountain, 1/3 for snowmaking and 1/3 for electrical generation. Some extremely back of the napkin math (using ChatGPT) shows that if 1.33 million cubic meters of water per year were used at 1000psi (this is a huge assumption) to generate electricity, at the standard 80% efficiency you could do 2,030 MWh per year. A random search for the average price of electricity in Switzerland shows 0.154 euros per kWh, so it seems like this could potentially generate 312,620 euros (at consumer rates...) worth of electricity per year. Given that the idea of pumped hydro is to pump when electricity is cheap and then generate at peak demands...I'm not quite sure how to do that math!
sparselogic 2y ago
Berkshire East is working on a micro pumped storage facility. Interestingly enough they’re already net producers of electricity. https://berkshireeast.com/the-resort/100-renewable-energy https://berkshireeast.com/the-resort/100-renewable-energy

pbmonster 2y ago

> 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. I don't think that's a concern. There's hydro plants with more than 6000' of head, leading to almost 3000 psi of pressure at the turbine and an exit velocity of the water jet of over 600 ft/s. From an engineering standpoint its totally manageable, and results in a highly efficient turbine. > 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. Good news is that adding another pipe with its own pump/generator is relatively cheap. Bad news is that 20 million gallons is a relatively small reservoir for pumped hydro, and increasing that is expensive. Still, seems like an easy and fast way to get some additional capacity online, especially in cases where a couple of megawatt of new solar get build in the vicinity of that damn...

gorbypark 2y ago
The only problem of 3000 PSI is 99% of the snowmaking pipelines out there would instantly blow up at that pressure :) You would also need to have PRVs anyways, because anything above about 700psi (900 if you are pushing it) is unusable/unsafe to use by the actual snowmakers and equipment. You also run soft 2" "fire" hose from a hydrant to a gun, and those are not rated for those pressures and the nozzles of the snow guns would wear out super quick as well (and the internal plumbing of the gun would probably blow up too). You'd generally have a max of about 900 PSI and ideally much lower as most of these pipes are relatively old, have no maintenance (until they blow up and a quick patch is made) and were welded up by "Bob the maintenance guy"! I suppose you could design a brand new system to be capable of such pressures when run in "generation" mode and still have some PRVs to keep it at a usable pressure during snowmaking operations.
- Danieru 2y ago
  If you pump up the hill, say to 3000PSI, then waste pressure on the way down: you lose said wasted energy. Pumped Hydrogen Storage requires maintaining full pressure across the entire pipe. Which should be reasonable: the "fill up" pipe already needs to go from the bottom to top at full pressure. Reversing the flow should be enough. The issue would be if the fill method was staged pumps.
lostlogin 2y ago
> an exit velocity of the water jet of over 600 ft/s. I’m completely unfamiliar with any of this stuff so please keep this in mind… If that’s the exit velocity, shouldn’t the turbine it’s spinning be geared to give a bit more resistance? Or is that the velocity of the water if its path is unimpeded?
- Danieru 2y ago
  Exit velocity is the nozzle exit speed. The water exists the nozzle and hits the turbine. With that said, turbine efficiency is not strictly based on resistance. Rather it is about extraction of energy. In a few designs it looks like resistance, others it is about redirection: https://www.energy.gov/eere/water/types-hydropower-turbines https://www.energy.gov/eere/water/types-hydropower-turbines

phreeza 2y ago

Flims in Switzerland has a kind of hybrid scheme planned where they use a reservoir for both snowmaking and hydroelectricity. https://www.wasserweltenflims.ch/wasser-in-flims/mehrzweckspeicher/ https://www.wasserweltenflims.ch/wasser-in-flims/mehrzwecksp...

maxerickson 2y ago
To what extent does it end up being "allow withdrawals for snowmaking" vs the thing being intended for snowmaking?
- phreeza 2y ago
  Well it's an enlargement of an existing snowmaking reservoir so I suspect it is the the latter. Probably part of a strategy to make the resort look eco-friendly.
  - gorbypark 2y ago
    Using google translate, it shows they are planning on upgrading the reservoir to 1 million cubic meters, which is about 264 million gallons from ~58 and that it will fill 3 times a year naturally, 4 times with pumps. 1/3 will be used to just keep the river flowing down the mountain, 1/3 for snowmaking and 1/3 for electrical generation. Some extremely back of the napkin math (using ChatGPT) shows that if 1.33 million cubic meters of water per year were used at 1000psi (this is a huge assumption) to generate electricity, at the standard 80% efficiency you could do 2,030 MWh per year. A random search for the average price of electricity in Switzerland shows 0.154 euros per kWh, so it seems like this could potentially generate 312,620 euros (at consumer rates...) worth of electricity per year. Given that the idea of pumped hydro is to pump when electricity is cheap and then generate at peak demands...I'm not quite sure how to do that math!

sparselogic 2y ago

Berkshire East is working on a micro pumped storage facility. Interestingly enough they’re already net producers of electricity. https://berkshireeast.com/the-resort/100-renewable-energy https://berkshireeast.com/the-resort/100-renewable-energy