9 ms·

Solving the world's trillion-dollar energy storage crisis. (multi-trillion, actually.) https://www.terramenthq.com/ https://www.terramenthq.com/ About a year a

Solving the world's trillion-dollar energy storage crisis. (multi-trillion, actually.) https://www.terramenthq.com/ https://www.terramenthq.com/ About a year ago, I started spending more time researching about climate change. I learned how important energy storage will be to enable renewable energy to displace fossil fuels. The more I read, the more fascinated I became with the idea of building underground pumped hydro energy storage. I found a research paper from the U.S. DOE written in 1984 showing that the idea was perfectly feasible and affordable, but it seems that nearly everyone has forgotten about it since. (they didn't build it at the time because the demand wasn't there yet. Now energy storage demand is growing exponentially) A year later, I'm applying for grant funding to get it built. I know that nearly everyone will tell me I can't do it because this or that reason. Because people don't like change and they're scared of big things even if the research shows it makes perfect sense. But I'm doing it anyways because no one else is getting it done. The idea is too compelling and too important to ignore. So here goes nothing!

dpflan 7y ago
How large is a typical system - how much land you need to excavate?
- syllable_studio 7y ago
  If we attach our installation to an existing reservoir, we'll take up nearly zero land above ground. If we build a new self-contained upper reservoir it will be about 0.5 miles on each side and 40 feet deep. It can be built with material excavated from the lower reservoir. This may seem large, but it's for a huge amount of storage 20GWh - enough to balance the load of a large city. And keep in mind that it's about the same size of the many large reservoirs that are scattered around a large city. Again, the most promising option would be to simply attach our installation to an existing reservoir. We don't use any additional water, we just borrow it. For an ample sized reservoir, each cycle would just raise and lower the water level by an inch or so. Another promising option is that we can even use the ocean as an upper reservoir. Salt water can be accommodated -- See our notes about the Okinawa Yanbaru Station. There are more details in our white paper posted on the website.
  - DoctorOetker 7y ago
    This would correspond to a height difference of about 1 km between upper and lower reservoir right?
    - syllable_studio 7y ago
      yup! More fun facts about a 1 km head height... Off-the-shelf turbines are actually spec'd for a max head height of something closer to .5 km. So the design calls for a double-drop. This design approach is taken from the DOE research linked on our website.
      - DoctorOetker 7y ago
        so where the geology allows it, why not go even deeper with the lowest reservoir, and put multiple turbines in series, with perhaps small reservoirs each .5 km? Then the total energy capacity is V * rho * g * h, so that energy store is proportional to height, while tunnel boring price is roughly constant as long as tunnel boring volume of the reservoirs is much larger than the volume of vertical shafts. I realize its a bit oversimplified but if we consider 2 prices: p1 price per volume for boring horizontally (for reservoirs), and p2 price per volume for boring vertically, then increasing the reservoir size by a volume delta V, requires boring 2 * delta V (upper and lower reservoir), while boring vertically the difference in height depends on the diameter...
  - jlevers 7y ago
    Why would a new upper reservoir need to be so wide and shallow, rather than having much less surface area and being much deeper?
    - syllable_studio 7y ago
      Good question, it doesn't really need to be, those numbers are partly just to visualize it. But we do have some reasons to keep it with more surface area: - less digging - less reinforcing needed - it's more stable - In some cases we're interested in floating solar on top of the reservoir which wouldn't work well if the reservoir was too deep. But it's certainly not out of the question to go deeper instead.
samstave 7y ago
Do you have a link to the 1984 paper? How can I help?
- jlevers 7y ago
  The link to the 1984 paper (from their website): https://www.osti.gov/biblio/6517343 https://www.osti.gov/biblio/6517343
- syllable_studio 7y ago
  Thanks to the commenter below who posted the link to the paper. Yes please! If you want to email me I'd love to see how we could work together. eric at terramenthq.com or syllablehq.com
jlevers 7y ago
I've actually been thinking about the issue of energy storage a lot recently -- I've read a ton about how lithium-ion battery production is exploding (usually not literally), but it seems unreasonable to store enormous amounts of renewable energy in a device that itself has to be replaced after a certain number of cycles. The device used for pumped energy storage -- a tank (to simplify greatly) -- basically never needs to be replaced. It's really cool to see a feasible alternative to batteries. I think climate change is the single most important problem anyone can be working on right now -- amazing that you've found such a massive lever to pull on this issue.
- nidhalbt 7y ago
  I think the point you just made about the rate of replacement of lithium-ion batteries is very pertinent to solar panels(to the point that many consider solar a scam)
  - jlevers 7y ago
    I've never heard that said before, but I'm interested to hear more. Do you have any sources on that? My understanding was that solar panels last quite a long time.
- davedx 7y ago
  > it seems unreasonable to store enormous amounts of renewable energy in a device that itself has to be replaced after a certain number of cycles. The device used for pumped energy storage -- a tank (to simplify greatly) -- basically never needs to be replaced. It's a fair point but I think that you oversimplify the pumped hydro case. Pumped hydro also has quite some electronic components (turbines/motors), electronics, and other moving parts (valves, overflows). I can imagine some of these components require semi-regular maintenance (hence the maintenance shaft in the diagram on the website of OP). You'd really have to run the numbers to see which costs more to maintain in the long term.
  - jlevers 7y ago
    That's a good point. I think it seems likely that given the relatively larger storage capacity per unit[0] with pumped hydro vs. batteries, that the overall maintenance costs -- including the environmental costs of materials needed -- would be lower, but you're absolutely right that we'd have to do the math to know for sure. [0]When I say "per unit," I just mean that a huge battery is made up of many cells that will need to be replaced individually, whereas large pumped hydro facilities are still only a small number of total reservoirs.
jpfr 7y ago
You are working on the most urgent and important topic that I know of. But it is also very hard to pull through. I wish you the best success. Here are two recent startups in the field with multi-million funding. They were serious approaches. Many people involved with good planning, etc. They still fizzled out when it came to installing their first capacity. https://www.power-technology.com/news/newsgaelectric-receives-90m-eu-grant-for-energy-storage-project-in-northern-ireland-5777106/ https://www.power-technology.com/news/newsgaelectric-receive... https://www.greentechmedia.com/articles/read/lightsail-energy-cheap-compressed-air-storage-hibernation https://www.greentechmedia.com/articles/read/lightsail-energ... I believe a reason for the funding problems is the high uncertainty for the economics of storage. Electrical energy is traded in a market. And your trading strategy in the market has a big impact on whether you earn money. Without solid numbers for energy storage and the expected trading outcome, investors will have a hard time.
- davedx 7y ago
  Yeah if you drill into how the Tesla grid storage solutions make money, it’s not just about the storage capacity but also about being able to respond to demand or frequency issues extremely quickly, which LiIon batteries are very good at. There’s a lot of money available to the fastest dispatcher.
  - galacticdessert 7y ago
    A lot of money seems excessive, at least in Europe. The flexibility market profitability depends a lot on the national market it plays in, as for instance the prices are quite low in Germany/north Europe, but very high in Australia. Rather than a way of making money, I like to think about flexibility and fast dispatching as an enabler for way more renewables to come online, and that is crucial for the human race right now.
    - davedx 7y ago
      Makes sense -- the grid storage system I read about was indeed the one they built for the Australian wind farm. I think there's a big gap for both types of storage - fast dispatching for intraday demand variations, replacing gas peakers, and more static storage as in the OP for multi-day gaps in renewable production such as periods of high pressure during winter when wind speeds and irradiance are both very low. Can't wait to see how this market develops.
jodrellblank 7y ago
Kinda surprised to hear that date, as the UK has a pumped hydro plant[1] which started construction in 1974 and opened in 1984; Tom Scott has a YouTube video about it[2]. It's not all underground, but the machinery is built into a hill and it pumps from a reservoir at the bottom up to the top when electricity is cheap, and is used as a fast-startup generator when demand is higher. Is it really more feasible to build the upper reservoir underground, than on top of, somewhere? Surely "on top of" is higher, easier to get to, easier to flatten, and much cheaper? [1] https://en.wikipedia.org/wiki/Dinorwig_Power_Station https://en.wikipedia.org/wiki/Dinorwig_Power_Station [2] https://www.youtube.com/watch?v=6Jx_bJgIFhI https://www.youtube.com/watch?v=6Jx_bJgIFhI
- davedx 7y ago
  The whole problem is there are entire countries that don’t have hills suitable for pumped hydro reservoirs - the Netherlands for example, which has a high energy demand per capita
  - bakuninsbart 7y ago
    The Netherlands is caught in an endless war against the Sea. They will make her give them the energy or die trying.
  - jodrellblank 7y ago
    So the plan is to build an underground reservoir, then dig deeper and build the lower reservoir? At that point, wouldn't it be easier to use the ocean as the upper reservoir, and dig down to build the lower reservoir, and pump seawater around? How much water do you have to move to power a house, anyway? It must be a lot - a truck pulling a tank of water goes up a hill as part of a journey without worrying about running out of gas, and they could be carrying 40,000 litres or 40 tons of water. Presumably there is no way you could move enough water at home to make a hydro plant - pump it up at night with cheap electricity and run it down at peak time to save money?
- ralphhughes 7y ago
  I live near Dinorwig pumped storage hydro and can highly recommend the tours they do if you're in the area. The tour bus drives into the mountain and stops literally a few metres from the generating turbines where you can get out and take photos of the huge underground turbine hall.
johnmorrison 7y ago
I hope to convey this in the least volatile manner, but I must bring it up. > I learned how important energy storage will be to enable renewable energy to displace fossil fuels. The above is a reasonable statement, however, your website says the following: > We can’t quit carbon without energy storage. To stop climate change, renewables must replace fossil fuels. > Without energy storage, renewables will fail to reach even 25% of the energy market by 2040. This will cause global temperatures to rise over 3°C, a level which will cause catastrophic climate damage. Those are not only misleading but outright lies. Now, I won't hide my bias here: I work on nuclear fission. But here's the reality: there are many possible pathways to net-zero carbon and limiting global temperature rise to well below 3°C (below 1.5°C in fact) To just list a few: * Massive adoption of nuclear fission alone * Development & massive adoption of nuclear fusion alone * Shift from coal&oil to natural gas, cleaner fossil fuels + scaling carbon capture/sequestration * Shift from fossil fuels to renewables + storage (probably not alone) Or any combination of those, in addition to a number of alternative approaches. --- Edit: Also, it should be noted that the energy sector alone only represents about 1/5 of the emissions problem. In order to get to net-zero GHG and stop anthroprogenic climate change, the clean energy sector needs to expand well past the current global TPES and supply net-zero electricity that allows for the decarbonization of the other main contributors: Agriculture, steel+cement+plastic, transportation, buildings&appliances, and flora loss leading to lost carbon stores (deforestation etc) Even if renewables and storage could supply 100% of our electricity or even total power supply, you would still only be 1/5 done solving climate change. There is no unitary solution. --- Acting as though renewables are necessary, instead of one of multiple options, is denial or malicious. In reality, renewable energy is nowhere near capable of reliably and safely taking on a large portion of our energy supply globally. It is expensive (you can make claims about unit cost, but what really matters is country-scale - look at German electricity prices vs. just about everywhere else), it is dangerous, it takes a lot of land area, and it is the least reliable. I don't want to spend a lot of time here stomping on renewables, but there is plenty of reason to, and my main point is that I feel it is unjust and immoral for you to claim that renewables "must replace fossil fuels" if we are to stop climate change. It's just not true, and you need to admit that. The energy industry is arguably one of if not the most important backbone of our modern society, and responsible for the safety and health of billions of people. Whether you're working on the generation or storage side, it is all our responsibility to be honest and make true claims - not to spread biased misinformation when it benefits your particular solution. I'd like to finish by making it clear I'm very happy you're working on your tech and I hope you succeed in making it the best it can be - renewables are certainly trending to higher adoption and we need reliable, efficient, scalable storage solution in order to avoid dangerous outages and other grid issues. You bring up valid criticisms of existing solutions, although I do think you should also be fair to those. Most things in life are a trade-off: maybe pumped hydro is a better majority solution for the grid, but lithium ion is an incredibly important, successful and expanding technology that needs to be given credit for its wide range of great applications. I hope this response has not been inflammatory: I just very much care about maintaining a truthful public discussion around energy. I wish you the best of luck, and I hope you can take something useful from this.
2rsf 7y ago
> affordable affordable, but efficiency is so-so. 70-80% according to Wikipedia [1] [1] https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity#Economic_efficiency https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...
- galacticdessert 7y ago
  It does not matter. The alternative is curtailing wind parks/solar generation, and wasting clean energy and even more money.
- tasuki 7y ago
  > affordable, but efficiency is so-so. 70-80% according to Wikipedia Say what? So-so? 70-80% efficiency sounds pretty damn amazing!
  - 2rsf 7y ago
    depends on the alternatives, which at the moment are indeed considerably worst
- syllable_studio 7y ago
  I love this quote: Hydro pumped storage is “astoundingly efficient…In this future world where we want renewables to get 20%, 30%, or 50% of our electricity generation, you need pumped hydro storage. It’s an incredible opportunity.” – U.S. Energy Secretary Dr. Steven Chu in 2009. Still true today. And actually, we think that 80-85% round trip is more accurate for our projects because we'll use the latest/greatest tech (variable-speed reversible francis style pump/generator turbines). I think the 70% from these figures is citing older projects with pump/turbines that were not quite as efficient.
raxxorrax 7y ago
One of my friends is a physicist that had the plan to install a closed cistern under his house and heat it up in summer with mostly solar energy. Looked really promising and he had all the numbers figured out to supply a family home with heating and warm water through a normal winter. Didn't do it in the end because there were some problems with building a cistern on his property and the large up front investment necessary. I wish you luck with your endeavor. I think you are correct that the problem of energy storage is the most important one to solve to allow renewables to really take off for general power supply. I also believe that the efficiency of storage is secondary to a degree as renewables can supply an enormous amount of energy. So loss from pumps or energy conversions are nearly insignificant. At least at the moment where energy storage is in such a bad shape. Certainly a lot more promising than having batteries everywhere.
- spditner 7y ago
  There's a large multi-tower project in Toronto that includes a heating and cooling system built by Enwave that incorporates a very large cistern / well, building on their prior success cooling the downtown core: https://www.cbc.ca/news/business/climate-heat-cooling-1.5437701 https://www.cbc.ca/news/business/climate-heat-cooling-1.5437...
- auiya 7y ago
  Funny to think the Romans were doing this thousands of years ago (and probably civilizations before them as well), and here we are just now coming around again to the idea of heating/cooling via cistern storage.
  - raxxorrax 7y ago
    True, but current techniques for thermal isolation could really make it quite efficient. The optimal cistern would be a giant ball of water under your house. I don't have his spreadsheet anymore, but it seemed really solid.
dangerface 7y ago
Pumping water up a mountain to store energy has been used around the world with much success, in my opinion it seems to be the most realistic way to store energy efficiently. If you can remove the mountain you could scale this out to every one in the world and single handedly solve this problem. There will be other problems to overcome but someone will figure it out why not you? I wish you all the best in this very important effort.
- JoeAltmaier 7y ago
  That's about 90%+ efficiency pumping it up, and generating it down (electrical conversion). So maybe 85% total storage efficiency. How's that compare to battery or other storage systems? Lithium is 98% by some sources.
  - DoctorOetker 7y ago
    the UPHS seems like a durable system that could store and deliver many more cycles than a battery?
    - JoeAltmaier 7y ago
      Yeah total cost of ownership would tend to even things out.
ace_of_spades 7y ago
If you are looking for an informed academic perspective on energy trading and renewables I can recommend to contact the following researchers [1]. Just write them an email and explain what you are working on, I could imagine they are going to be interested! 1: http://www.is3.uni-koeln.de/ http://www.is3.uni-koeln.de/

dpflan 7y ago

How large is a typical system - how much land you need to excavate?

syllable_studio 7y ago
If we attach our installation to an existing reservoir, we'll take up nearly zero land above ground. If we build a new self-contained upper reservoir it will be about 0.5 miles on each side and 40 feet deep. It can be built with material excavated from the lower reservoir. This may seem large, but it's for a huge amount of storage 20GWh - enough to balance the load of a large city. And keep in mind that it's about the same size of the many large reservoirs that are scattered around a large city. Again, the most promising option would be to simply attach our installation to an existing reservoir. We don't use any additional water, we just borrow it. For an ample sized reservoir, each cycle would just raise and lower the water level by an inch or so. Another promising option is that we can even use the ocean as an upper reservoir. Salt water can be accommodated -- See our notes about the Okinawa Yanbaru Station. There are more details in our white paper posted on the website.
- DoctorOetker 7y ago
  This would correspond to a height difference of about 1 km between upper and lower reservoir right?
  - syllable_studio 7y ago
    yup! More fun facts about a 1 km head height... Off-the-shelf turbines are actually spec'd for a max head height of something closer to .5 km. So the design calls for a double-drop. This design approach is taken from the DOE research linked on our website.
    - DoctorOetker 7y ago
      so where the geology allows it, why not go even deeper with the lowest reservoir, and put multiple turbines in series, with perhaps small reservoirs each .5 km? Then the total energy capacity is V * rho * g * h, so that energy store is proportional to height, while tunnel boring price is roughly constant as long as tunnel boring volume of the reservoirs is much larger than the volume of vertical shafts. I realize its a bit oversimplified but if we consider 2 prices: p1 price per volume for boring horizontally (for reservoirs), and p2 price per volume for boring vertically, then increasing the reservoir size by a volume delta V, requires boring 2 * delta V (upper and lower reservoir), while boring vertically the difference in height depends on the diameter...
- jlevers 7y ago
  Why would a new upper reservoir need to be so wide and shallow, rather than having much less surface area and being much deeper?
  - syllable_studio 7y ago
    Good question, it doesn't really need to be, those numbers are partly just to visualize it. But we do have some reasons to keep it with more surface area: - less digging - less reinforcing needed - it's more stable - In some cases we're interested in floating solar on top of the reservoir which wouldn't work well if the reservoir was too deep. But it's certainly not out of the question to go deeper instead.

samstave 7y ago

Do you have a link to the 1984 paper? How can I help?

jlevers 7y ago
The link to the 1984 paper (from their website): https://www.osti.gov/biblio/6517343 https://www.osti.gov/biblio/6517343
syllable_studio 7y ago
Thanks to the commenter below who posted the link to the paper. Yes please! If you want to email me I'd love to see how we could work together. eric at terramenthq.com or syllablehq.com

jlevers 7y ago

I've actually been thinking about the issue of energy storage a lot recently -- I've read a ton about how lithium-ion battery production is exploding (usually not literally), but it seems unreasonable to store enormous amounts of renewable energy in a device that itself has to be replaced after a certain number of cycles. The device used for pumped energy storage -- a tank (to simplify greatly) -- basically never needs to be replaced. It's really cool to see a feasible alternative to batteries. I think climate change is the single most important problem anyone can be working on right now -- amazing that you've found such a massive lever to pull on this issue.

nidhalbt 7y ago
I think the point you just made about the rate of replacement of lithium-ion batteries is very pertinent to solar panels(to the point that many consider solar a scam)
- jlevers 7y ago
  I've never heard that said before, but I'm interested to hear more. Do you have any sources on that? My understanding was that solar panels last quite a long time.
davedx 7y ago
> it seems unreasonable to store enormous amounts of renewable energy in a device that itself has to be replaced after a certain number of cycles. The device used for pumped energy storage -- a tank (to simplify greatly) -- basically never needs to be replaced. It's a fair point but I think that you oversimplify the pumped hydro case. Pumped hydro also has quite some electronic components (turbines/motors), electronics, and other moving parts (valves, overflows). I can imagine some of these components require semi-regular maintenance (hence the maintenance shaft in the diagram on the website of OP). You'd really have to run the numbers to see which costs more to maintain in the long term.
- jlevers 7y ago
  That's a good point. I think it seems likely that given the relatively larger storage capacity per unit[0] with pumped hydro vs. batteries, that the overall maintenance costs -- including the environmental costs of materials needed -- would be lower, but you're absolutely right that we'd have to do the math to know for sure. [0]When I say "per unit," I just mean that a huge battery is made up of many cells that will need to be replaced individually, whereas large pumped hydro facilities are still only a small number of total reservoirs.

jpfr 7y ago

You are working on the most urgent and important topic that I know of. But it is also very hard to pull through. I wish you the best success. Here are two recent startups in the field with multi-million funding. They were serious approaches. Many people involved with good planning, etc. They still fizzled out when it came to installing their first capacity. https://www.power-technology.com/news/newsgaelectric-receives-90m-eu-grant-for-energy-storage-project-in-northern-ireland-5777106/ https://www.power-technology.com/news/newsgaelectric-receive... https://www.greentechmedia.com/articles/read/lightsail-energy-cheap-compressed-air-storage-hibernation https://www.greentechmedia.com/articles/read/lightsail-energ... I believe a reason for the funding problems is the high uncertainty for the economics of storage. Electrical energy is traded in a market. And your trading strategy in the market has a big impact on whether you earn money. Without solid numbers for energy storage and the expected trading outcome, investors will have a hard time.

davedx 7y ago
Yeah if you drill into how the Tesla grid storage solutions make money, it’s not just about the storage capacity but also about being able to respond to demand or frequency issues extremely quickly, which LiIon batteries are very good at. There’s a lot of money available to the fastest dispatcher.
- galacticdessert 7y ago
  A lot of money seems excessive, at least in Europe. The flexibility market profitability depends a lot on the national market it plays in, as for instance the prices are quite low in Germany/north Europe, but very high in Australia. Rather than a way of making money, I like to think about flexibility and fast dispatching as an enabler for way more renewables to come online, and that is crucial for the human race right now.
  - davedx 7y ago
    Makes sense -- the grid storage system I read about was indeed the one they built for the Australian wind farm. I think there's a big gap for both types of storage - fast dispatching for intraday demand variations, replacing gas peakers, and more static storage as in the OP for multi-day gaps in renewable production such as periods of high pressure during winter when wind speeds and irradiance are both very low. Can't wait to see how this market develops.

jodrellblank 7y ago

Kinda surprised to hear that date, as the UK has a pumped hydro plant[1] which started construction in 1974 and opened in 1984; Tom Scott has a YouTube video about it[2]. It's not all underground, but the machinery is built into a hill and it pumps from a reservoir at the bottom up to the top when electricity is cheap, and is used as a fast-startup generator when demand is higher. Is it really more feasible to build the upper reservoir underground, than on top of, somewhere? Surely "on top of" is higher, easier to get to, easier to flatten, and much cheaper? [1] https://en.wikipedia.org/wiki/Dinorwig_Power_Station https://en.wikipedia.org/wiki/Dinorwig_Power_Station [2] https://www.youtube.com/watch?v=6Jx_bJgIFhI https://www.youtube.com/watch?v=6Jx_bJgIFhI

davedx 7y ago
The whole problem is there are entire countries that don’t have hills suitable for pumped hydro reservoirs - the Netherlands for example, which has a high energy demand per capita
- bakuninsbart 7y ago
  The Netherlands is caught in an endless war against the Sea. They will make her give them the energy or die trying.
- jodrellblank 7y ago
  So the plan is to build an underground reservoir, then dig deeper and build the lower reservoir? At that point, wouldn't it be easier to use the ocean as the upper reservoir, and dig down to build the lower reservoir, and pump seawater around? How much water do you have to move to power a house, anyway? It must be a lot - a truck pulling a tank of water goes up a hill as part of a journey without worrying about running out of gas, and they could be carrying 40,000 litres or 40 tons of water. Presumably there is no way you could move enough water at home to make a hydro plant - pump it up at night with cheap electricity and run it down at peak time to save money?
ralphhughes 7y ago
I live near Dinorwig pumped storage hydro and can highly recommend the tours they do if you're in the area. The tour bus drives into the mountain and stops literally a few metres from the generating turbines where you can get out and take photos of the huge underground turbine hall.

johnmorrison 7y ago

I hope to convey this in the least volatile manner, but I must bring it up. > I learned how important energy storage will be to enable renewable energy to displace fossil fuels. The above is a reasonable statement, however, your website says the following: > We can’t quit carbon without energy storage. To stop climate change, renewables must replace fossil fuels. > Without energy storage, renewables will fail to reach even 25% of the energy market by 2040. This will cause global temperatures to rise over 3°C, a level which will cause catastrophic climate damage. Those are not only misleading but outright lies. Now, I won't hide my bias here: I work on nuclear fission. But here's the reality: there are many possible pathways to net-zero carbon and limiting global temperature rise to well below 3°C (below 1.5°C in fact) To just list a few: * Massive adoption of nuclear fission alone * Development & massive adoption of nuclear fusion alone * Shift from coal&oil to natural gas, cleaner fossil fuels + scaling carbon capture/sequestration * Shift from fossil fuels to renewables + storage (probably not alone) Or any combination of those, in addition to a number of alternative approaches. --- Edit: Also, it should be noted that the energy sector alone only represents about 1/5 of the emissions problem. In order to get to net-zero GHG and stop anthroprogenic climate change, the clean energy sector needs to expand well past the current global TPES and supply net-zero electricity that allows for the decarbonization of the other main contributors: Agriculture, steel+cement+plastic, transportation, buildings&appliances, and flora loss leading to lost carbon stores (deforestation etc) Even if renewables and storage could supply 100% of our electricity or even total power supply, you would still only be 1/5 done solving climate change. There is no unitary solution. --- Acting as though renewables are necessary, instead of one of multiple options, is denial or malicious. In reality, renewable energy is nowhere near capable of reliably and safely taking on a large portion of our energy supply globally. It is expensive (you can make claims about unit cost, but what really matters is country-scale - look at German electricity prices vs. just about everywhere else), it is dangerous, it takes a lot of land area, and it is the least reliable. I don't want to spend a lot of time here stomping on renewables, but there is plenty of reason to, and my main point is that I feel it is unjust and immoral for you to claim that renewables "must replace fossil fuels" if we are to stop climate change. It's just not true, and you need to admit that. The energy industry is arguably one of if not the most important backbone of our modern society, and responsible for the safety and health of billions of people. Whether you're working on the generation or storage side, it is all our responsibility to be honest and make true claims - not to spread biased misinformation when it benefits your particular solution. I'd like to finish by making it clear I'm very happy you're working on your tech and I hope you succeed in making it the best it can be - renewables are certainly trending to higher adoption and we need reliable, efficient, scalable storage solution in order to avoid dangerous outages and other grid issues. You bring up valid criticisms of existing solutions, although I do think you should also be fair to those. Most things in life are a trade-off: maybe pumped hydro is a better majority solution for the grid, but lithium ion is an incredibly important, successful and expanding technology that needs to be given credit for its wide range of great applications. I hope this response has not been inflammatory: I just very much care about maintaining a truthful public discussion around energy. I wish you the best of luck, and I hope you can take something useful from this.

2rsf 7y ago

> affordable affordable, but efficiency is so-so. 70-80% according to Wikipedia [1] [1] https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity#Economic_efficiency https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...

galacticdessert 7y ago
It does not matter. The alternative is curtailing wind parks/solar generation, and wasting clean energy and even more money.
tasuki 7y ago
> affordable, but efficiency is so-so. 70-80% according to Wikipedia Say what? So-so? 70-80% efficiency sounds pretty damn amazing!
- 2rsf 7y ago
  depends on the alternatives, which at the moment are indeed considerably worst
syllable_studio 7y ago
I love this quote: Hydro pumped storage is “astoundingly efficient…In this future world where we want renewables to get 20%, 30%, or 50% of our electricity generation, you need pumped hydro storage. It’s an incredible opportunity.” – U.S. Energy Secretary Dr. Steven Chu in 2009. Still true today. And actually, we think that 80-85% round trip is more accurate for our projects because we'll use the latest/greatest tech (variable-speed reversible francis style pump/generator turbines). I think the 70% from these figures is citing older projects with pump/turbines that were not quite as efficient.

raxxorrax 7y ago

One of my friends is a physicist that had the plan to install a closed cistern under his house and heat it up in summer with mostly solar energy. Looked really promising and he had all the numbers figured out to supply a family home with heating and warm water through a normal winter. Didn't do it in the end because there were some problems with building a cistern on his property and the large up front investment necessary. I wish you luck with your endeavor. I think you are correct that the problem of energy storage is the most important one to solve to allow renewables to really take off for general power supply. I also believe that the efficiency of storage is secondary to a degree as renewables can supply an enormous amount of energy. So loss from pumps or energy conversions are nearly insignificant. At least at the moment where energy storage is in such a bad shape. Certainly a lot more promising than having batteries everywhere.

spditner 7y ago
There's a large multi-tower project in Toronto that includes a heating and cooling system built by Enwave that incorporates a very large cistern / well, building on their prior success cooling the downtown core: https://www.cbc.ca/news/business/climate-heat-cooling-1.5437701 https://www.cbc.ca/news/business/climate-heat-cooling-1.5437...
auiya 7y ago
Funny to think the Romans were doing this thousands of years ago (and probably civilizations before them as well), and here we are just now coming around again to the idea of heating/cooling via cistern storage.
- raxxorrax 7y ago
  True, but current techniques for thermal isolation could really make it quite efficient. The optimal cistern would be a giant ball of water under your house. I don't have his spreadsheet anymore, but it seemed really solid.

dangerface 7y ago

Pumping water up a mountain to store energy has been used around the world with much success, in my opinion it seems to be the most realistic way to store energy efficiently. If you can remove the mountain you could scale this out to every one in the world and single handedly solve this problem. There will be other problems to overcome but someone will figure it out why not you? I wish you all the best in this very important effort.

JoeAltmaier 7y ago
That's about 90%+ efficiency pumping it up, and generating it down (electrical conversion). So maybe 85% total storage efficiency. How's that compare to battery or other storage systems? Lithium is 98% by some sources.
- DoctorOetker 7y ago
  the UPHS seems like a durable system that could store and deliver many more cycles than a battery?
  - JoeAltmaier 7y ago
    Yeah total cost of ownership would tend to even things out.

ace_of_spades 7y ago

If you are looking for an informed academic perspective on energy trading and renewables I can recommend to contact the following researchers [1]. Just write them an email and explain what you are working on, I could imagine they are going to be interested! 1: http://www.is3.uni-koeln.de/ http://www.is3.uni-koeln.de/