8 ms·

From liquid air to supercapacitors, energy storage is poised for a breakthrough

50 points by jsingleton 11y ago

dragontamer 11y ago
A good overview, although missing Vanadium Redox Flow batteries (liquid battery), which is one of my favorites. Redox Flow batteries can be pumped into storage tanks and distributed (theoretically anyway). In contrast, the entire set off Lithium Ion battery needs to be connected to the grid to take advantage of its storage, you can "pump" Redox Flow batteries into storage tanks to increase capacity without increasing power. For day/night cycle storage (or longer), I'd expect Redox Flow to be more cost efficient than Lithium Ion, despite LiIon having numerous advantages (density / power / etc. etc.). Mainly because you can save on "Power Output" and instead build larger and larger tanks to store the charged electrolyte. LiIons get more and more expensive ($$$ per KW-hr storage) the "bigger" they get. Redox Flow batteries achieve scalability (cheaper $$$ per KW-hr the bigger they get). I do realize I'm imprecisely using the word "bigger", but I hope yall will forgive me on that :-) My personal favorites: 1. Pumped Hydro -- Old technology, but a favorite of mine. Very simple design, just take advantage of lakes that already exist in your vicinity and use the water in the lake as a gravity storage device. 2. Flywheels -- Store energy by spinning a heavy object. Spin-spin-spin... spinning and gyroscopes are cool. 3. Vanadium Redox Flow Battery -- Liquid batteries, how cool is that?
- AnkhMorporkian 11y ago
  > (...) you can "pump" Redox Flow batteries into storage tanks to increase capacity without increasing power. Why wouldn't you keep them at maximum capacity all the time?
  - dragontamer 11y ago
    Cost efficiency. If your neighborhood only needs 50MW of power, but you want 1000 MWhr of storage (~20 hours at full power), a Redox flow battery would be able to do that. Or if you were building a Hospital (Lets say 5MW of power) and need to spec out 3-days of power (ie: 360 MWhrs of storage on 5MW Power), you just build a tank that can store a lot of the electrolyte. I guess... the best way of putting it is that Lithium Ion batteries are like AAA batteries, while a Redox Flow battery could be configured as a larger D battery. D Batteries don't give any more power or voltage than AAA batteries, but are more efficient for energy storage. It is very easy to imagine how to build a 3000MW-hr 50MW Redox Flow battery (just build a huge storage tank). It is almost impossible to imagine the same with Lithium Ion (I guess you can build massive Li-Ion cells, but note that the Tesla is powered by tiny 3.7V 18650 cells wired up together. So it really hasn't been done before) Day/Night cycle storage is a low power (Megawatts) high-storage (Megawatt-hours) use case. Lithium Ion batteries are more useful for high-power / medium-storage situations (like frequency balancing, or maybe a couple hours-long storage). Flywheels are exactly the opposite. They are high-power low-storage devices. Flywheels would be very useful for smoothing out power when birds / clouds come up in front of solar panels (for example). Its easy to build a 300MW flywheel with almost no capacity (only a few minutes of storage). Flywheels could be used when a power-source goes offline suddenly, while a few minutes need to be spent spinning up a new power-source. (ex: Main grid goes down, you need 30 seconds before your diesel generator fully turns on. The flywheel will keep very high-power for the next 2 minutes while things switch over). Although supercapacitors are also a promising technology for this problem. Different storage technologies for different purposes.
  - zardo 11y ago
    They would be charged. You're confusing energy and power, by increasing the reservoir sizes you increase energy storage capacity but not the speed at which the total stored energy can change (power).
  - deleted 11y ago
    [deleted]
- jsingleton 11y ago
  Pumped storage is great if you have the geography for it. In a lot of places (such as the UK) it's all already in use.
  - RobertoG 11y ago
    Yes. Some places, like the island of 'el hierro', even are disconnected of the main grid: http://www.npr.org/sections/parallels/2014/09/17/349223674/tiny-spanish-island-nears-its-goal-100-percent-renewable-energy http://www.npr.org/sections/parallels/2014/09/17/349223674/t...
jsingleton 11y ago
I posted this yesterday but today there's a story about "Welsh home installs UK's first Tesla Powerwall storage battery". Good news. http://www.theguardian.com/environment/2016/feb/05/welsh-home-installs-uks-first-tesla-powerwall-storage-battery http://www.theguardian.com/environment/2016/feb/05/welsh-hom... This project to store energy in trains also looks interesting. http://www.aresnorthamerica.com http://www.aresnorthamerica.com
jonawesomegreen 11y ago
I've spent the last couple years working on a very interesting project using ultra-capacitors for energy storage. We are storing 33kWh of energy in ultra capacitors, charging and discharging with a very short period (seconds) for peak-demand shaving. It really is an exciting time for energy storage technology. I think we are going to see a lot of cool innovation in the next few years, even just finding new uses for existing technologies.
- saosebastiao 11y ago
  What sort of volume/weight dimensions are required for 33kWh of ultra capacitors?
  - jonawesomegreen 11y ago
    They are quite large, but in the particular application weight and volume are not a huge concern. All sitting side by side they are about 20 meters long, 3 meters high, and a meter deep. Probably weighs on the order of 15 tonnes.
    - zachrose 11y ago
      Wow, how much capacitance is that?
      - aexaey 11y ago
        16.3 megafarads, assuming typical cell voltage of 2.7v, and total energy of 33kWh: http://www.wolframalpha.com/input/?i=33kWh%2F%282.7v%29**2 http://www.wolframalpha.com/input/?i=33kWh%2F%282.7v%29**2
- deleted 11y ago
  [deleted]
- deleted 11y ago
  [deleted]
- oh_sigh 11y ago
beat 11y ago
Energy storage is such a no-brainer. It makes solar/wind viable for both base load and peak load generation. The numbers required are very measurable and predictable. It doesn't require magical, exotic technology (as the elevated reservoir and compressed air mechanisms show). There's always going to be some thermal losses in transformation, but they're going to be pretty similar across technologies. Another nice thing about solar + storage is that it can scale very small, very inexpensively. Imagine putting a set of solar panels or a wind turbine plus some storage in a village in Africa. It may not be worth wiring it to an expensive grid, but just getting electricity there can make so many other differences. Beyond that, the ability to small-scale and decouple reduces the power and influence of large corporations and the government-industrial complexes that wreak so much havoc. You don't need the drama and abuse of the petroleum or nuclear industries anymore.
- SilasX 11y ago
  Scalable? Compressed air and reservoirs are about the opposite of energy-dense and require a lot of space per unit energy. I'm optimistic about the role that energy storage can play in converting green tech to base-load capability, but it seems like it requires some technological advances unless you want to devote huge territories to becoming low-density batteries.
  - beat 11y ago
    I'm not talking about physical size. I'm talking about cost and complexity. An air tank with a compressor pump at one end and a turbine at the other is simple, reliable, well-understood, off-the-shelf technology. How much energy can you store in an air tank that would fit on the back of a truck? Hook it up to another truck full of solar panels, and you have a local electric grid, capable of powering at least a few buildings, at very reasonable cost and minimal sophistication required for operation and maintenance.
    - SilasX 11y ago
      Scalability covers spatial scalability, and so necessarily involves talking about physical size relative to energy stored in this context.
oconnore 11y ago
These buzz articles always focus on the sexy energy storage methods: lithium ion, liquid batteries, electrolysis, supercapacitors, etc. I've seen very little evidence that these can compete on either $/kWh, or efficiency, with pumped hydro (where available), thermal (Isentropic Energy Ltd [1]), or kinetic. [1]: https://www.greentechmedia.com/articles/read/Isentropics-Pumped-Heat-System-Stores-Energy-at-Grid-Scale https://www.greentechmedia.com/articles/read/Isentropics-Pum...
- ohitsdom 11y ago
  Correct me if I'm wrong, but none of the options you listed are portable.
  - mikeash 11y ago
    The article is all about storage for the electrical grid, to shave peak demand and allow more wind/solar use, so portability isn't a requirement.
  - oconnore 11y ago
    Right. In the context of grid storage of renewable energy, that doesn't matter. You need a li-ion or similar in your phone and your laptop (and maybe your car), but that doesn't make it the best tech for flattening out a peaky solar/wind grid.
nordify 11y ago
Could somebody enlighten me on the economics of energy storage? The local retail energy prices are approximately 10c/kWh year round, rain or shine. The price is fixed, unless you buy a contract based on the spot market. All the energy storage products I've heard about cost more or about the same per kWh just to store the energy. So even if the energy to charge the energy storage was free, it still would not make economic sense to store energy if you have grid power. Am I missing something or is consumer energy storage only for off-grid applications?
- beat 11y ago
  Solar/wind are inconsistent, and their output doesn't map to consumption patterns. So a totally solar/wind grid would require massive overbuilding in order to provide sufficient power for peaks. By caching the surplus generated when supply exceeds demand, we can significantly reduce the overall supply footprint, by using the generated supply much more efficiently.
  - nordify 11y ago
    But why bother storing the solar/wind excess, if storage costs exceed traditional generation costs? For a purely economical perspective, it does not make sense.
    - beat 11y ago
      Because in the long run, storage costs will go down, and traditional generation costs will go up. At some point, there's a crossing where storage becomes cheaper. Much of that has to do with economies of scale and driving technological improvement with demand. Beyond that, there are externalized costs to continuing a system that depends on fossil fuels and complex/expensive nuclear plants. In a macro world, governments and public utilities should be taking the externalized costs into account.
      - nordify 11y ago
        So the answer to my question is that the economics of energy storage do not work, but may at some point of the future? I get both the technical and ecological argument, my point is that the economics to drive the change aren't here (yet).
stcredzero 11y ago
Contextually relevant question: How much would it cost to do a major revamp of the North American electrical grid? (For various values of "major revamp" of course.) I found this article that mentions a $2 Trillion figure from Rocky Mountain Institute, but I take that with a big grain of salt. [1] Since the patents around Tesla's Supercharger are open, what about the idea of giving the US highway commission a few hundreds of millions to double the number of Supercharger stations? (This would create more demand while not improving the infrastructure, but I would benefit personally.) [1] - http://www.renewableenergyworld.com/news/2015/04/us-power-grids-2-trillion-upgrade-needs-european-efficiency.html
- mikeash 11y ago
  Superchargers only work with Teslas, and Tesla is doing fine when it comes to doubling the number of installations on their own (there are currently 270, and they installed 113 of those last year), so having the government come in and install them doesn't seem like a good use of money. Further, what's the relevance of Supercharger stations to electrical storage? Maybe I'm missing something but that seems like an irrelevant tangent here.
1024core 11y ago
This stuff is always "poised for breakthrough". But we are still stuck on LiOn batteries, which have been around for what, 20 years? Wake me up when we have something that doubles the capacity of LiOn batteries in a similar form-factor and safety rating, propelling Teslas to 600km+ ranges. That would be a real "breakthrough".
gravypod 11y ago
"It doesn’t always rain when you need water, so we have reservoirs - but we don’t have the same system for electricity,” says Jill Cainey, director of the UK’s" Actually... we do. It is called pumped hydroelectric storage [1], and it is essentially just a reservoir, a pump, and a turbine. [1] http://energystorage.org/energy-storage/technologies/pumped-hydroelectric-storage http://energystorage.org/energy-storage/technologies/pumped-...

50 points by jsingleton 11y ago

A good overview, although missing Vanadium Redox Flow batteries (liquid battery), which is one of my favorites. Redox Flow batteries can be pumped into storage tanks and distributed (theoretically anyway). In contrast, the entire set off Lithium Ion battery needs to be connected to the grid to take advantage of its storage, you can "pump" Redox Flow batteries into storage tanks to increase capacity without increasing power. For day/night cycle storage (or longer), I'd expect Redox Flow to be more cost efficient than Lithium Ion, despite LiIon having numerous advantages (density / power / etc. etc.). Mainly because you can save on "Power Output" and instead build larger and larger tanks to store the charged electrolyte. LiIons get more and more expensive ($$$ per KW-hr storage) the "bigger" they get. Redox Flow batteries achieve scalability (cheaper $$$ per KW-hr the bigger they get). I do realize I'm imprecisely using the word "bigger", but I hope yall will forgive me on that :-) My personal favorites: 1. Pumped Hydro -- Old technology, but a favorite of mine. Very simple design, just take advantage of lakes that already exist in your vicinity and use the water in the lake as a gravity storage device. 2. Flywheels -- Store energy by spinning a heavy object. Spin-spin-spin... spinning and gyroscopes are cool. 3. Vanadium Redox Flow Battery -- Liquid batteries, how cool is that?

AnkhMorporkian 11y ago
> (...) you can "pump" Redox Flow batteries into storage tanks to increase capacity without increasing power. Why wouldn't you keep them at maximum capacity all the time?
- dragontamer 11y ago
  Cost efficiency. If your neighborhood only needs 50MW of power, but you want 1000 MWhr of storage (~20 hours at full power), a Redox flow battery would be able to do that. Or if you were building a Hospital (Lets say 5MW of power) and need to spec out 3-days of power (ie: 360 MWhrs of storage on 5MW Power), you just build a tank that can store a lot of the electrolyte. I guess... the best way of putting it is that Lithium Ion batteries are like AAA batteries, while a Redox Flow battery could be configured as a larger D battery. D Batteries don't give any more power or voltage than AAA batteries, but are more efficient for energy storage. It is very easy to imagine how to build a 3000MW-hr 50MW Redox Flow battery (just build a huge storage tank). It is almost impossible to imagine the same with Lithium Ion (I guess you can build massive Li-Ion cells, but note that the Tesla is powered by tiny 3.7V 18650 cells wired up together. So it really hasn't been done before) Day/Night cycle storage is a low power (Megawatts) high-storage (Megawatt-hours) use case. Lithium Ion batteries are more useful for high-power / medium-storage situations (like frequency balancing, or maybe a couple hours-long storage). Flywheels are exactly the opposite. They are high-power low-storage devices. Flywheels would be very useful for smoothing out power when birds / clouds come up in front of solar panels (for example). Its easy to build a 300MW flywheel with almost no capacity (only a few minutes of storage). Flywheels could be used when a power-source goes offline suddenly, while a few minutes need to be spent spinning up a new power-source. (ex: Main grid goes down, you need 30 seconds before your diesel generator fully turns on. The flywheel will keep very high-power for the next 2 minutes while things switch over). Although supercapacitors are also a promising technology for this problem. Different storage technologies for different purposes.
- zardo 11y ago
  They would be charged. You're confusing energy and power, by increasing the reservoir sizes you increase energy storage capacity but not the speed at which the total stored energy can change (power).
- deleted 11y ago
  [deleted]
jsingleton 11y ago
Pumped storage is great if you have the geography for it. In a lot of places (such as the UK) it's all already in use.
- RobertoG 11y ago
  Yes. Some places, like the island of 'el hierro', even are disconnected of the main grid: http://www.npr.org/sections/parallels/2014/09/17/349223674/tiny-spanish-island-nears-its-goal-100-percent-renewable-energy http://www.npr.org/sections/parallels/2014/09/17/349223674/t...

jsingleton 11y ago

I posted this yesterday but today there's a story about "Welsh home installs UK's first Tesla Powerwall storage battery". Good news. http://www.theguardian.com/environment/2016/feb/05/welsh-home-installs-uks-first-tesla-powerwall-storage-battery http://www.theguardian.com/environment/2016/feb/05/welsh-hom... This project to store energy in trains also looks interesting. http://www.aresnorthamerica.com http://www.aresnorthamerica.com

jonawesomegreen 11y ago

I've spent the last couple years working on a very interesting project using ultra-capacitors for energy storage. We are storing 33kWh of energy in ultra capacitors, charging and discharging with a very short period (seconds) for peak-demand shaving. It really is an exciting time for energy storage technology. I think we are going to see a lot of cool innovation in the next few years, even just finding new uses for existing technologies.

saosebastiao 11y ago
What sort of volume/weight dimensions are required for 33kWh of ultra capacitors?
- jonawesomegreen 11y ago
  They are quite large, but in the particular application weight and volume are not a huge concern. All sitting side by side they are about 20 meters long, 3 meters high, and a meter deep. Probably weighs on the order of 15 tonnes.
  - zachrose 11y ago
    Wow, how much capacitance is that?
    - aexaey 11y ago
      16.3 megafarads, assuming typical cell voltage of 2.7v, and total energy of 33kWh: http://www.wolframalpha.com/input/?i=33kWh%2F%282.7v%29**2 http://www.wolframalpha.com/input/?i=33kWh%2F%282.7v%29**2
deleted 11y ago
[deleted]
deleted 11y ago
[deleted]
oh_sigh 11y ago

beat 11y ago

Energy storage is such a no-brainer. It makes solar/wind viable for both base load and peak load generation. The numbers required are very measurable and predictable. It doesn't require magical, exotic technology (as the elevated reservoir and compressed air mechanisms show). There's always going to be some thermal losses in transformation, but they're going to be pretty similar across technologies. Another nice thing about solar + storage is that it can scale very small, very inexpensively. Imagine putting a set of solar panels or a wind turbine plus some storage in a village in Africa. It may not be worth wiring it to an expensive grid, but just getting electricity there can make so many other differences. Beyond that, the ability to small-scale and decouple reduces the power and influence of large corporations and the government-industrial complexes that wreak so much havoc. You don't need the drama and abuse of the petroleum or nuclear industries anymore.

SilasX 11y ago
Scalable? Compressed air and reservoirs are about the opposite of energy-dense and require a lot of space per unit energy. I'm optimistic about the role that energy storage can play in converting green tech to base-load capability, but it seems like it requires some technological advances unless you want to devote huge territories to becoming low-density batteries.
- beat 11y ago
  I'm not talking about physical size. I'm talking about cost and complexity. An air tank with a compressor pump at one end and a turbine at the other is simple, reliable, well-understood, off-the-shelf technology. How much energy can you store in an air tank that would fit on the back of a truck? Hook it up to another truck full of solar panels, and you have a local electric grid, capable of powering at least a few buildings, at very reasonable cost and minimal sophistication required for operation and maintenance.
  - SilasX 11y ago
    Scalability covers spatial scalability, and so necessarily involves talking about physical size relative to energy stored in this context.

oconnore 11y ago

These buzz articles always focus on the sexy energy storage methods: lithium ion, liquid batteries, electrolysis, supercapacitors, etc. I've seen very little evidence that these can compete on either $/kWh, or efficiency, with pumped hydro (where available), thermal (Isentropic Energy Ltd [1]), or kinetic. [1]: https://www.greentechmedia.com/articles/read/Isentropics-Pumped-Heat-System-Stores-Energy-at-Grid-Scale https://www.greentechmedia.com/articles/read/Isentropics-Pum...

ohitsdom 11y ago
Correct me if I'm wrong, but none of the options you listed are portable.
- mikeash 11y ago
  The article is all about storage for the electrical grid, to shave peak demand and allow more wind/solar use, so portability isn't a requirement.
- oconnore 11y ago
  Right. In the context of grid storage of renewable energy, that doesn't matter. You need a li-ion or similar in your phone and your laptop (and maybe your car), but that doesn't make it the best tech for flattening out a peaky solar/wind grid.

nordify 11y ago

Could somebody enlighten me on the economics of energy storage? The local retail energy prices are approximately 10c/kWh year round, rain or shine. The price is fixed, unless you buy a contract based on the spot market. All the energy storage products I've heard about cost more or about the same per kWh just to store the energy. So even if the energy to charge the energy storage was free, it still would not make economic sense to store energy if you have grid power. Am I missing something or is consumer energy storage only for off-grid applications?

beat 11y ago
Solar/wind are inconsistent, and their output doesn't map to consumption patterns. So a totally solar/wind grid would require massive overbuilding in order to provide sufficient power for peaks. By caching the surplus generated when supply exceeds demand, we can significantly reduce the overall supply footprint, by using the generated supply much more efficiently.
- nordify 11y ago
  But why bother storing the solar/wind excess, if storage costs exceed traditional generation costs? For a purely economical perspective, it does not make sense.
  - beat 11y ago
    Because in the long run, storage costs will go down, and traditional generation costs will go up. At some point, there's a crossing where storage becomes cheaper. Much of that has to do with economies of scale and driving technological improvement with demand. Beyond that, there are externalized costs to continuing a system that depends on fossil fuels and complex/expensive nuclear plants. In a macro world, governments and public utilities should be taking the externalized costs into account.
    - nordify 11y ago
      So the answer to my question is that the economics of energy storage do not work, but may at some point of the future? I get both the technical and ecological argument, my point is that the economics to drive the change aren't here (yet).

stcredzero 11y ago

Contextually relevant question: How much would it cost to do a major revamp of the North American electrical grid? (For various values of "major revamp" of course.) I found this article that mentions a $2 Trillion figure from Rocky Mountain Institute, but I take that with a big grain of salt. [1] Since the patents around Tesla's Supercharger are open, what about the idea of giving the US highway commission a few hundreds of millions to double the number of Supercharger stations? (This would create more demand while not improving the infrastructure, but I would benefit personally.) [1] - http://www.renewableenergyworld.com/news/2015/04/us-power-grids-2-trillion-upgrade-needs-european-efficiency.html

mikeash 11y ago
Superchargers only work with Teslas, and Tesla is doing fine when it comes to doubling the number of installations on their own (there are currently 270, and they installed 113 of those last year), so having the government come in and install them doesn't seem like a good use of money. Further, what's the relevance of Supercharger stations to electrical storage? Maybe I'm missing something but that seems like an irrelevant tangent here.

1024core 11y ago

This stuff is always "poised for breakthrough". But we are still stuck on LiOn batteries, which have been around for what, 20 years? Wake me up when we have something that doubles the capacity of LiOn batteries in a similar form-factor and safety rating, propelling Teslas to 600km+ ranges. That would be a real "breakthrough".

gravypod 11y ago

"It doesn’t always rain when you need water, so we have reservoirs - but we don’t have the same system for electricity,” says Jill Cainey, director of the UK’s" Actually... we do. It is called pumped hydroelectric storage [1], and it is essentially just a reservoir, a pump, and a turbine. [1] http://energystorage.org/energy-storage/technologies/pumped-hydroelectric-storage http://energystorage.org/energy-storage/technologies/pumped-...