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They will go like... storing energy is an unsolvable problem Yeah sure. But if you have an abundance of electrical power you can literally lift up concrete bl

by atoav 4y ago

They will go like... storing energy is an unsolvable problem Yeah sure. But if you have an abundance of electrical power you can literally lift up concrete blocks with a crane and generate electricity by letting them down. You can pump water up and use turbines. If you live in a flat area you can do the same in mine shafts. A German guy developed a way of cutting huge granite cylinders out of solid rock that you can lift up and let down producing high pressure waterflows that can be used to store energy. You can split water into hydrogen and oxygen and run turbines off of it, you can charge batteries. You can warm up sand in insulated containers and use the heat to power turbines. There is so many ways to store energy it is hard to enumerate them. And if you have much more wind and solar power than you need you don't even need to worry that much about the efficiency of the storage system. Sure, you're gonna select the one that you can finance, maintain and find the space for, but a lot of that stuff could be built literally everywhere. Storage is no argument any serious engineer would pull out. Serious engineers would say that our electrical grids are not capable to deliver that much energy if we try to replace every form of energy with electrical energy — and they would be right. But this is again not an impossible problem to solve. We know how to transmit electricity pretty well. We just need to build the infrastructure.

armada651 4y ago
> But if you have an abundance of electrical power you can literally lift up concrete blocks with a crane and generate electricity by letting them down. That doesn't seem like the best idea if you think about it: https://youtu.be/iGGOjD_OtAM https://youtu.be/iGGOjD_OtAM
- 10u152 4y ago
  Yeah it’s a terrible idea. Pumped hydro or compressed air is way better on every front.
  - VBprogrammer 4y ago
    Isn't the round trip efficiency of compressed air terrible? You lose a lot of energy as heat when you compress air which you then have to resupply when expanding the compressed air to avoid things freezing over.
    - pfdietz 4y ago
      There is adiabatic compressed air, where the heat of compression is transfered to a thermal store, cooling the compressed air before it's injected into the storage cavern. Then, on discharge, the heat is recovered from the thermal store and used to reheat the air. This illustrates, btw, that compressed air doesn't actually storage energy! The energy content of a gas is the kinetic energy of its molecules (and some small contribution from the potential energy of molecules at the moments they bounce off each other, but that's typically minor). The kinetic energy of the molecules is a function of temperature, but not of pressure. What the air is doing is acting as a store of reduced entropy, which can later be exploited to convert that separate heat back to work at high efficiency. However, one could also do this by PTES, Pumped Thermal Energy Storage, where a reversible thermal cycle produces heat and cold, which are stored separately, then brought back together to recover the work. This is like adiabatic CAES, but instead of storing the cooled compressed air, it is expanded through a turbine and the cold of the resulting expanded gas is stored (say in a tank of mild cryogenic hexane).
- ZeroGravitas 4y ago
  Their point isn't that that's the best idea, but that we have lots of things that would actually work, and between them there was never any reason to worry too much about it. Like you might not know what your going to eat next Friday, you don't know if the cafeteria might sell out of chicken, or if they'll be doing a special on your favourite fish. But that's different from "I will starve next Friday" or "I am allergic to nuts, and there will be nothing but nuts to eat" and it certainly doesn't mean you should put poison in your food today. It's not physics that the limit, it's economics that suggests green hydrogen will probably be the winner, since as well as storage it has other uses. Similarly for batteries, the dual use tips the balance economically.
  - Manuel_D 4y ago
    > Their point isn't that that's the best idea, but that we have lots of things that would actually work, and between them there was never any reason to worry too much about it. And the above commenter's point is that it doesn't actually work. The fact that so many support and energy policy that amounts to "whatever, we'll figure out storage eventually" is astounding. If that's the mentality you're going to take, just let fusion solve all our problems.
- _ph_ 4y ago
  I don't like that video, but yes, I don't think that design is the solution for the future. Using water als gravitational storage is quite well developed and has additional benefits (like storing precious water for droughts). But that is the nice thing going forward: there are many different ways of storing electricity and many of them will be tried. I am sure there will be a lot of new feasible ways of doing so in the market soon.
- badtension 4y ago
  Energy storage is still hard, unfortunately. I don't think any gravity storage other than pumped hydro (where nature allows for it) is viable. The question I've been asking myself in case we were to go for battery energy storage: would we be better off using decentralized system with solar + battery on every home / small community or just make massive installations and keep using existing power grid to move energy to homes?
  - andyferris 4y ago
    Decentralized doesn't work so well for places that require a high ratio of electrical power to solar radiance - like refineries, factories, medium and high density housing, electric vehical fast chargers, low density housing in places that get cold in winter, and more. So a large fraction of society will need to import some energy from somewhere (either from the grid or a fuel like hydrogen). Fully decentralised solar + battery might be the best option for rural / semi-rural settings, but even low-density suburbia somewhere sunny could likely benefit from having all those batteries and panels working together via the existing grid.
    - badtension 4y ago
      > Decentralized doesn't work so well for places that require a high ratio of electrical power to solar radiance Yeah, another example that comes to mind are flats - the roof is a bit small to cover all residents' energy needs. As always in life it seems that "it depends" but I think you are right about remote places. It is of course always better to have electrical grid since you shift the maintenance to someone else (as long as the power delivered is reliable and cost effective). The one issue I can think of is current grid may not be able to handle many small energy producers - they can be cut off when peak power is a problem. In those cases individual prosumers would benefit from having a local battery storage system that fit their needs, even when connected to the grid.
    - pasttense01 4y ago
      Remember the goal to electrify everything. For the home owner this includes space heating. So if you live in the snowbelt you need to have the battery capacity to handle a two week Polar Vortex with temperatures below zero degrees Fahrenheit with very little sun with your fully decentralized solar system. This will require a very expensive battery system!
- amirhirsch 4y ago
  On land you just can’t make it tall enough, you get roughly 2.5kWh of potential energy per km of delta-h per ton of mass. I think if you store energy in a gravity battery out in the ocean where the depths are 10km, you may end up with a system competitive with pumped hydro. The incremental cost of a ton of mass and a ton of buoyancy are probably gonna be a factor of 2 to 10 less than lithium batteries. For any storage project: if it needs $1B of infrastructure costs for wires, dynamos, robots etc. just to start then you must be talking about building at least 10GWh before it is practical. so probably millions of tons for an oceanic gravity battery
jokethrowaway 4y ago
Lifting heavy things up is cool but expensive. Batteries are way more compact but don't last too long. It's a hard problem. Hopefully one of those magic battery tech from the past will be ready at some point. On the contrary, the difficulty of switching to full electricity is very country dependant: some countries rely heavily on gas, some use electricity for everything. I didn't have gas in any of my houses for the last 10+ years. On the automotive front, you already have the market and the high price of EV to make sure EV adoption will be gradual. I'm sure over time we can adapt to the increased demand with incremental improvements.
- badtension 4y ago
  Do you know what's up with molten salt batteries? I've heard GE was big on it but then after investing a ton of money they just closed it down. Is the technology not viable? Seemed to me like a green solution that is working ok and can be used now.
makomk 4y ago
There are numerous ways that you can store some amount of power - batteries, various potential energy storage options, hydrogen and other synthetic fuels, even stuff like flywheels. The unsolved problem is storing power on the vast scale actually needed to make an 100% renewable grid possible. In particular I think the numbers on storing energy by lifting and lowering concrete blocks work out really bad and a long way from being useful as a form of energy storage.
- lettergram 4y ago
  Exactly. You’d probably be better off assuming no new grid connections tbh. You can effective force a distributed energy network. It just wouldn’t work for cities. I don’t think a lot of people outside of homesteaders or people working in energy understand. I can spend $25k for the solar I need for my house, but I’ll be spending another $50k for energy storage. And I’m in a more southern region… if you live somewhere in Europe, particularly the north, you’d need $50k solar and $50k storage. Btw that $50k only covers batteries for 36-48 hrs of usage. Have 10 days of heavily cloud cover, gotta pull out the diesel engine. I’ve looked at alternatives energy stores and nothing really has capacity we need. There’s ways to cut energy usage, there’s other forms of energy capture, but battery storage is basically it for single homes. Fly-wheels and what not might work to stabilize grids for 24-36hrs. But I highly doubt on a week of energy, for instance. So you still have the same issues as single homes. You need the ability to start up engines (so to speak).
  - pasttense01 4y ago
    Of course there are alternative energy stores which have the capacity we need. What do you think we are using for energy storage now? Now we have huge piles of coal, natural gas stored in huge caverns, massive tank farms storing petroleum products. So the question is can we convert the electrical energy when wind and solar are at maximum output into gases, liquids, solids. The answer is yes. One obvious gas is hydrogen. And if the liquids and solids include carbon then to be carbon neutral we need to pull as much carbon out of the atmosphere as we will put back in (carbon capture technologies). So it can be done. The problem is the higher cost than fossil fuels.
osigurdson 4y ago
This is a useful chart (though it would be nice if efficiency was included). https://en.wikipedia.org/wiki/Hydrogen_storage#/media/File:Available_storage_technologies,_their_capacity_and_discharge_time.jpg https://en.wikipedia.org/wiki/Hydrogen_storage#/media/File:A...
credit_guy 4y ago
Storage via gravitational potential energy is extraordinarily inefficient. Let's say you have a medium city, like Columbus, OH. This city purchases about 890 GWh of electricity per year [1] for costumers and street lights. Let's say they need to store 100 GWh. A kg of matter raised 1 meter stores about 10 joules, or watt-seconds. We need to store 100 times 3600 billion of watt-seconds, which is 360 trillion. You can trade mass for height. For example you can raise 36 trillion kg to a height of 1 meter. That's 36 billion tons or gigatons (GT). Or you can raise 3.6 GT to a height of 10 meters, just 36 MT to a 1km hight. Let's say you want to use blocks of stone. The total US production of blocks of stone in 2021 was 2.3 million tons [2]. You need 15 times as much to only cover Columbus, OH, and only assuming a 100% efficiency in the conversion of the energy from electricity to gravitational potential energy and back. The only substance that can be useful for this type of storage is water. But even for water, you need the same huge quantities. 36 million tons of water is a lake with a surface area of 1 square kilometer and a depth of 36 meters. If you have some mountains around you, then you can do it. But Columbus, OH is out of luck. It does not have mountains, or even hills around it. Building an artificial hill that's 1000 meters tall, that has a 1 km2 lake at the top with a depth of 36 meters is a monumental undertaking, that was never attempted. Of course, you can try to play around with the tradeoffs. Maybe you build a lower hill with a larger footprint. But how long is it going to take to offset the emissions from such a huge construction project? Bottom line: pumped hydro makes sense, if geography allows you. If not, it is uneconomical by many orders of magnitude. [1] https://www.columbus.gov/greenpower/ https://www.columbus.gov/greenpower/ [2] https://pubs.usgs.gov/periodicals/mcs2022/mcs2022-stone-dimension.pdf https://pubs.usgs.gov/periodicals/mcs2022/mcs2022-stone-dime...
- jrmg 4y ago
  This city purchases about 890 GWh of electricity per year [1] for costumers and street lights. Let's say they need to store 100 GWh. Why do they need to store over 1/9th of their yearly energy usage?
  - credit_guy 4y ago
    If you switch to renewables, you need to store energy.
marcosdumay 4y ago
I wonder what the FUD line will become once solar plants start coming with 2 or 3 hours of storage because it optimized the ROI of the inverting and transforming equipment. (This shouldn't take too long, since the battery costs are almost there already.)
- ZeroGravitas 4y ago
  Already happening in the US: https://www.rechargenews.com/energy-transition/us-energy-storage-market-hard-wired-for-still-robust-expansion-through-2023-s-p/2-1-1181306 https://www.rechargenews.com/energy-transition/us-energy-sto... > The research house expects 9.4GW of energy storage capacity to come online this year and a further 15.6GW in 2023 ,with nearly 60% to be co-located with other – chiefly solar – power plants. > Developers added 1.33GW of energy storage capacity in the fourth quarter of 2021, exceeding the previous two years combined, and energised more than 3GW last year.
Manuel_D 4y ago
The world uses 60 TWh of electricity daily. About twice that in terms of total energy use. Even just one hour of energy storage is a massive undertaking. Estimates to reach a 100% renewable grid call for 3 weeks of storage: https://pv-magazine-usa.com/2018/03/01/12-hours-energy-storage-80-percent-wind-solar/ https://pv-magazine-usa.com/2018/03/01/12-hours-energy-stora... No solution we have can deliver even remotely close to that amount of storage. Sure, you can build giant flywheels or pulleys or what have you. But can you build them at the required scale? What is the rate at which you can build them? > Sure, you're gonna select the one that you can finance, maintain and find the space for My point is that this is way, way harder than you seem to think.

by atoav 4y ago

armada651 4y ago

> But if you have an abundance of electrical power you can literally lift up concrete blocks with a crane and generate electricity by letting them down. That doesn't seem like the best idea if you think about it: https://youtu.be/iGGOjD_OtAM https://youtu.be/iGGOjD_OtAM

10u152 4y ago
Yeah it’s a terrible idea. Pumped hydro or compressed air is way better on every front.
- VBprogrammer 4y ago
  Isn't the round trip efficiency of compressed air terrible? You lose a lot of energy as heat when you compress air which you then have to resupply when expanding the compressed air to avoid things freezing over.
  - pfdietz 4y ago
    There is adiabatic compressed air, where the heat of compression is transfered to a thermal store, cooling the compressed air before it's injected into the storage cavern. Then, on discharge, the heat is recovered from the thermal store and used to reheat the air. This illustrates, btw, that compressed air doesn't actually storage energy! The energy content of a gas is the kinetic energy of its molecules (and some small contribution from the potential energy of molecules at the moments they bounce off each other, but that's typically minor). The kinetic energy of the molecules is a function of temperature, but not of pressure. What the air is doing is acting as a store of reduced entropy, which can later be exploited to convert that separate heat back to work at high efficiency. However, one could also do this by PTES, Pumped Thermal Energy Storage, where a reversible thermal cycle produces heat and cold, which are stored separately, then brought back together to recover the work. This is like adiabatic CAES, but instead of storing the cooled compressed air, it is expanded through a turbine and the cold of the resulting expanded gas is stored (say in a tank of mild cryogenic hexane).
ZeroGravitas 4y ago
Their point isn't that that's the best idea, but that we have lots of things that would actually work, and between them there was never any reason to worry too much about it. Like you might not know what your going to eat next Friday, you don't know if the cafeteria might sell out of chicken, or if they'll be doing a special on your favourite fish. But that's different from "I will starve next Friday" or "I am allergic to nuts, and there will be nothing but nuts to eat" and it certainly doesn't mean you should put poison in your food today. It's not physics that the limit, it's economics that suggests green hydrogen will probably be the winner, since as well as storage it has other uses. Similarly for batteries, the dual use tips the balance economically.
- Manuel_D 4y ago
  > Their point isn't that that's the best idea, but that we have lots of things that would actually work, and between them there was never any reason to worry too much about it. And the above commenter's point is that it doesn't actually work. The fact that so many support and energy policy that amounts to "whatever, we'll figure out storage eventually" is astounding. If that's the mentality you're going to take, just let fusion solve all our problems.
_ph_ 4y ago
I don't like that video, but yes, I don't think that design is the solution for the future. Using water als gravitational storage is quite well developed and has additional benefits (like storing precious water for droughts). But that is the nice thing going forward: there are many different ways of storing electricity and many of them will be tried. I am sure there will be a lot of new feasible ways of doing so in the market soon.
badtension 4y ago
Energy storage is still hard, unfortunately. I don't think any gravity storage other than pumped hydro (where nature allows for it) is viable. The question I've been asking myself in case we were to go for battery energy storage: would we be better off using decentralized system with solar + battery on every home / small community or just make massive installations and keep using existing power grid to move energy to homes?
- andyferris 4y ago
  Decentralized doesn't work so well for places that require a high ratio of electrical power to solar radiance - like refineries, factories, medium and high density housing, electric vehical fast chargers, low density housing in places that get cold in winter, and more. So a large fraction of society will need to import some energy from somewhere (either from the grid or a fuel like hydrogen). Fully decentralised solar + battery might be the best option for rural / semi-rural settings, but even low-density suburbia somewhere sunny could likely benefit from having all those batteries and panels working together via the existing grid.
  - badtension 4y ago
    > Decentralized doesn't work so well for places that require a high ratio of electrical power to solar radiance Yeah, another example that comes to mind are flats - the roof is a bit small to cover all residents' energy needs. As always in life it seems that "it depends" but I think you are right about remote places. It is of course always better to have electrical grid since you shift the maintenance to someone else (as long as the power delivered is reliable and cost effective). The one issue I can think of is current grid may not be able to handle many small energy producers - they can be cut off when peak power is a problem. In those cases individual prosumers would benefit from having a local battery storage system that fit their needs, even when connected to the grid.
  - pasttense01 4y ago
    Remember the goal to electrify everything. For the home owner this includes space heating. So if you live in the snowbelt you need to have the battery capacity to handle a two week Polar Vortex with temperatures below zero degrees Fahrenheit with very little sun with your fully decentralized solar system. This will require a very expensive battery system!
amirhirsch 4y ago
On land you just can’t make it tall enough, you get roughly 2.5kWh of potential energy per km of delta-h per ton of mass. I think if you store energy in a gravity battery out in the ocean where the depths are 10km, you may end up with a system competitive with pumped hydro. The incremental cost of a ton of mass and a ton of buoyancy are probably gonna be a factor of 2 to 10 less than lithium batteries. For any storage project: if it needs $1B of infrastructure costs for wires, dynamos, robots etc. just to start then you must be talking about building at least 10GWh before it is practical. so probably millions of tons for an oceanic gravity battery

jokethrowaway 4y ago

Lifting heavy things up is cool but expensive. Batteries are way more compact but don't last too long. It's a hard problem. Hopefully one of those magic battery tech from the past will be ready at some point. On the contrary, the difficulty of switching to full electricity is very country dependant: some countries rely heavily on gas, some use electricity for everything. I didn't have gas in any of my houses for the last 10+ years. On the automotive front, you already have the market and the high price of EV to make sure EV adoption will be gradual. I'm sure over time we can adapt to the increased demand with incremental improvements.

badtension 4y ago
Do you know what's up with molten salt batteries? I've heard GE was big on it but then after investing a ton of money they just closed it down. Is the technology not viable? Seemed to me like a green solution that is working ok and can be used now.

makomk 4y ago

There are numerous ways that you can store some amount of power - batteries, various potential energy storage options, hydrogen and other synthetic fuels, even stuff like flywheels. The unsolved problem is storing power on the vast scale actually needed to make an 100% renewable grid possible. In particular I think the numbers on storing energy by lifting and lowering concrete blocks work out really bad and a long way from being useful as a form of energy storage.

lettergram 4y ago
Exactly. You’d probably be better off assuming no new grid connections tbh. You can effective force a distributed energy network. It just wouldn’t work for cities. I don’t think a lot of people outside of homesteaders or people working in energy understand. I can spend $25k for the solar I need for my house, but I’ll be spending another $50k for energy storage. And I’m in a more southern region… if you live somewhere in Europe, particularly the north, you’d need $50k solar and $50k storage. Btw that $50k only covers batteries for 36-48 hrs of usage. Have 10 days of heavily cloud cover, gotta pull out the diesel engine. I’ve looked at alternatives energy stores and nothing really has capacity we need. There’s ways to cut energy usage, there’s other forms of energy capture, but battery storage is basically it for single homes. Fly-wheels and what not might work to stabilize grids for 24-36hrs. But I highly doubt on a week of energy, for instance. So you still have the same issues as single homes. You need the ability to start up engines (so to speak).
- pasttense01 4y ago
  Of course there are alternative energy stores which have the capacity we need. What do you think we are using for energy storage now? Now we have huge piles of coal, natural gas stored in huge caverns, massive tank farms storing petroleum products. So the question is can we convert the electrical energy when wind and solar are at maximum output into gases, liquids, solids. The answer is yes. One obvious gas is hydrogen. And if the liquids and solids include carbon then to be carbon neutral we need to pull as much carbon out of the atmosphere as we will put back in (carbon capture technologies). So it can be done. The problem is the higher cost than fossil fuels.

osigurdson 4y ago

This is a useful chart (though it would be nice if efficiency was included). https://en.wikipedia.org/wiki/Hydrogen_storage#/media/File:Available_storage_technologies,_their_capacity_and_discharge_time.jpg https://en.wikipedia.org/wiki/Hydrogen_storage#/media/File:A...

credit_guy 4y ago

Storage via gravitational potential energy is extraordinarily inefficient. Let's say you have a medium city, like Columbus, OH. This city purchases about 890 GWh of electricity per year [1] for costumers and street lights. Let's say they need to store 100 GWh. A kg of matter raised 1 meter stores about 10 joules, or watt-seconds. We need to store 100 times 3600 billion of watt-seconds, which is 360 trillion. You can trade mass for height. For example you can raise 36 trillion kg to a height of 1 meter. That's 36 billion tons or gigatons (GT). Or you can raise 3.6 GT to a height of 10 meters, just 36 MT to a 1km hight. Let's say you want to use blocks of stone. The total US production of blocks of stone in 2021 was 2.3 million tons [2]. You need 15 times as much to only cover Columbus, OH, and only assuming a 100% efficiency in the conversion of the energy from electricity to gravitational potential energy and back. The only substance that can be useful for this type of storage is water. But even for water, you need the same huge quantities. 36 million tons of water is a lake with a surface area of 1 square kilometer and a depth of 36 meters. If you have some mountains around you, then you can do it. But Columbus, OH is out of luck. It does not have mountains, or even hills around it. Building an artificial hill that's 1000 meters tall, that has a 1 km2 lake at the top with a depth of 36 meters is a monumental undertaking, that was never attempted. Of course, you can try to play around with the tradeoffs. Maybe you build a lower hill with a larger footprint. But how long is it going to take to offset the emissions from such a huge construction project? Bottom line: pumped hydro makes sense, if geography allows you. If not, it is uneconomical by many orders of magnitude. [1] https://www.columbus.gov/greenpower/ https://www.columbus.gov/greenpower/ [2] https://pubs.usgs.gov/periodicals/mcs2022/mcs2022-stone-dimension.pdf https://pubs.usgs.gov/periodicals/mcs2022/mcs2022-stone-dime...

jrmg 4y ago
This city purchases about 890 GWh of electricity per year [1] for costumers and street lights. Let's say they need to store 100 GWh. Why do they need to store over 1/9th of their yearly energy usage?
- credit_guy 4y ago
  If you switch to renewables, you need to store energy.

marcosdumay 4y ago

I wonder what the FUD line will become once solar plants start coming with 2 or 3 hours of storage because it optimized the ROI of the inverting and transforming equipment. (This shouldn't take too long, since the battery costs are almost there already.)

ZeroGravitas 4y ago
Already happening in the US: https://www.rechargenews.com/energy-transition/us-energy-storage-market-hard-wired-for-still-robust-expansion-through-2023-s-p/2-1-1181306 https://www.rechargenews.com/energy-transition/us-energy-sto... > The research house expects 9.4GW of energy storage capacity to come online this year and a further 15.6GW in 2023 ,with nearly 60% to be co-located with other – chiefly solar – power plants. > Developers added 1.33GW of energy storage capacity in the fourth quarter of 2021, exceeding the previous two years combined, and energised more than 3GW last year.

Manuel_D 4y ago

The world uses 60 TWh of electricity daily. About twice that in terms of total energy use. Even just one hour of energy storage is a massive undertaking. Estimates to reach a 100% renewable grid call for 3 weeks of storage: https://pv-magazine-usa.com/2018/03/01/12-hours-energy-storage-80-percent-wind-solar/ https://pv-magazine-usa.com/2018/03/01/12-hours-energy-stora... No solution we have can deliver even remotely close to that amount of storage. Sure, you can build giant flywheels or pulleys or what have you. But can you build them at the required scale? What is the rate at which you can build them? > Sure, you're gonna select the one that you can finance, maintain and find the space for My point is that this is way, way harder than you seem to think.