5 ms·

Storing Renewable Energy Using Thermodynamics

13 points by martind81 9y ago

hprotagonist 9y ago
forgive me if this is totally petty, but: "thermodynamic" is an adjective, not a noun. "Storing Renewable Energy Using Thermodynamic" ... what, exactly?
- craig1f 9y ago
  First, not saying I believe that these guys are legit, but "thermodynamics" is a noun. Thermodynamic energy is a type of energy, like chemical energy is a type of energy. There is also nuclear, stored, potential, light, kinetic, and I'm sure I'm missing a few. These are all basic physics concepts. These guys are claiming to be able to store the energy as thermal energy, and then get it back out at 70% efficiency without much degradation inside of 25 years. All these ideas are plausible from a physics point of view, but I don't buy this simply because it requires an efficient way of converting heat to energy. If this existed, it would already be a holy grail for other reasons. Being able to turn the waste-heat from an engine back into more energy efficiently would be incredible. Right now, to get energy from heat, you typically need the heated material to be near something that's very cold, and you use the difference in temperature to get energy out of it. Or you boil water and spin turbines. It sounds like MAYBE that's what these guys are doing, if what they are claiming to be able to do is legitimate.
  - hprotagonist 9y ago
    thermodynamics, yes. "thermodynamic" is an adjective that denotes "having to do with thermodynamics". this is utterly petty, i know, but it really jars.
- tlb 9y ago
  Indeed. I fixed the title.
luhn 9y ago
They claim 0.05€ (~0.06USD) per KWh lifetime cost. Anybody know how that compares to current prices of grid-scale batteries? I can't find a up-to-date source.
- aidenn0 9y ago
  Pumped hydro is about 3x as expensive, and batteries I think are still more expensive than pumped hydro, so it's absurdly cheap.
  - petre 9y ago
    Pumped hydro and flywheels are at least demonstrated cost effective solutions. This? They don't even provide any details.
Asturaz 9y ago
The issue with storing energy is that en investment of building infrastructure to transport the energy where it is deficit of energy is a more market safe solution.
smartmic 9y ago
I am missing a profound description of the technology. Where is the innovation? The website containing only some key words is too sparse to arouse serious interest.
- quantum_state 9y ago
  Same observation here ... seems to be a bit nebulous ...
thinkcontext 9y ago
Interesting concept. Wake me up when they demonstrate 10MWh.
IndrekR 9y ago
Assuming about 300K ambient temperature (on site, above ground), 800K working temperature (store the heat at 500°C) and that the second law of thermodynamics still holds, the roundtrip efficiency can not be 70%. It must be below 40%, and not just a bit below.
- mojomark 9y ago
  I don't follow. The second law of thermodynamics doesn't say anything about the specific efficiency limits of an energy conversion or storage system. Ideal reversible systems can maintain entropy if fully isolated (e.g. insulated). In real systems, perfect isolation is impractical, of course, but the resulting loss of energy is a function of the shortomings of the manufacturers of the system (e.g. use of low R factor insulation, high resistance electrical conductors, or poorly shaped pump impellers, etc), not some simple "2nd law limit".
  - cameldrv 9y ago
    https://en.wikipedia.org/wiki/Carnot%27s_theorem_(thermodynamics) https://en.wikipedia.org/wiki/Carnot%27s_theorem_(thermodyna...
    - tlb 9y ago
      Heat->mechanical energy can only be (1-Tc/Th) efficient. But mechanical energy->heat can be 1/(1-Tc/Th) efficient, so you can get close to unity round trip efficiency. That's why people use heat pumps to heat buildings, because you get more heat out than energy in (the extra heat comes from the ground).
      - eximius 9y ago
        I need further explanation before this makes sense to me. How can M->H have greater than 100% efficiency? You mentioned getting heat from the ground, but that only happens when the ground heat is greater than T_h, right? At which point it just sounds like geothermal but with extra steps.
Nomentatus 9y ago
Similar tech, I expect: https://arstechnica.com/information-technology/2017/04/startup-says-it-can-make-compressed-air-energy-storage-scheme-dirt-cheap/ https://arstechnica.com/information-technology/2017/04/start... https://www.thenational.ae/uae/compressed-air-the-battery-of-the-future-1.338460 https://www.thenational.ae/uae/compressed-air-the-battery-of... https://www.engadget.com/2013/09/16/sustainx-turns-on-first-modern-megawatt-scale-air-battery/ https://www.engadget.com/2013/09/16/sustainx-turns-on-first-...

13 points by martind81 9y ago

forgive me if this is totally petty, but: "thermodynamic" is an adjective, not a noun. "Storing Renewable Energy Using Thermodynamic" ... what, exactly?

craig1f 9y ago
First, not saying I believe that these guys are legit, but "thermodynamics" is a noun. Thermodynamic energy is a type of energy, like chemical energy is a type of energy. There is also nuclear, stored, potential, light, kinetic, and I'm sure I'm missing a few. These are all basic physics concepts. These guys are claiming to be able to store the energy as thermal energy, and then get it back out at 70% efficiency without much degradation inside of 25 years. All these ideas are plausible from a physics point of view, but I don't buy this simply because it requires an efficient way of converting heat to energy. If this existed, it would already be a holy grail for other reasons. Being able to turn the waste-heat from an engine back into more energy efficiently would be incredible. Right now, to get energy from heat, you typically need the heated material to be near something that's very cold, and you use the difference in temperature to get energy out of it. Or you boil water and spin turbines. It sounds like MAYBE that's what these guys are doing, if what they are claiming to be able to do is legitimate.
- hprotagonist 9y ago
  thermodynamics, yes. "thermodynamic" is an adjective that denotes "having to do with thermodynamics". this is utterly petty, i know, but it really jars.
tlb 9y ago
Indeed. I fixed the title.

luhn 9y ago

They claim 0.05€ (~0.06USD) per KWh lifetime cost. Anybody know how that compares to current prices of grid-scale batteries? I can't find a up-to-date source.

aidenn0 9y ago
Pumped hydro is about 3x as expensive, and batteries I think are still more expensive than pumped hydro, so it's absurdly cheap.
- petre 9y ago
  Pumped hydro and flywheels are at least demonstrated cost effective solutions. This? They don't even provide any details.

Asturaz 9y ago

The issue with storing energy is that en investment of building infrastructure to transport the energy where it is deficit of energy is a more market safe solution.

smartmic 9y ago

I am missing a profound description of the technology. Where is the innovation? The website containing only some key words is too sparse to arouse serious interest.

quantum_state 9y ago
Same observation here ... seems to be a bit nebulous ...

thinkcontext 9y ago

Interesting concept. Wake me up when they demonstrate 10MWh.

IndrekR 9y ago

Assuming about 300K ambient temperature (on site, above ground), 800K working temperature (store the heat at 500°C) and that the second law of thermodynamics still holds, the roundtrip efficiency can not be 70%. It must be below 40%, and not just a bit below.

mojomark 9y ago
I don't follow. The second law of thermodynamics doesn't say anything about the specific efficiency limits of an energy conversion or storage system. Ideal reversible systems can maintain entropy if fully isolated (e.g. insulated). In real systems, perfect isolation is impractical, of course, but the resulting loss of energy is a function of the shortomings of the manufacturers of the system (e.g. use of low R factor insulation, high resistance electrical conductors, or poorly shaped pump impellers, etc), not some simple "2nd law limit".
- cameldrv 9y ago
  https://en.wikipedia.org/wiki/Carnot%27s_theorem_(thermodynamics) https://en.wikipedia.org/wiki/Carnot%27s_theorem_(thermodyna...
  - tlb 9y ago
    Heat->mechanical energy can only be (1-Tc/Th) efficient. But mechanical energy->heat can be 1/(1-Tc/Th) efficient, so you can get close to unity round trip efficiency. That's why people use heat pumps to heat buildings, because you get more heat out than energy in (the extra heat comes from the ground).
    - eximius 9y ago
      I need further explanation before this makes sense to me. How can M->H have greater than 100% efficiency? You mentioned getting heat from the ground, but that only happens when the ground heat is greater than T_h, right? At which point it just sounds like geothermal but with extra steps.

Nomentatus 9y ago

Similar tech, I expect: https://arstechnica.com/information-technology/2017/04/startup-says-it-can-make-compressed-air-energy-storage-scheme-dirt-cheap/ https://arstechnica.com/information-technology/2017/04/start... https://www.thenational.ae/uae/compressed-air-the-battery-of-the-future-1.338460 https://www.thenational.ae/uae/compressed-air-the-battery-of... https://www.engadget.com/2013/09/16/sustainx-turns-on-first-modern-megawatt-scale-air-battery/ https://www.engadget.com/2013/09/16/sustainx-turns-on-first-...