5 ms·

The round trip efficiencies for these compressed air storage have typically been terrible (<50%). That's mostly because compressing air is super inefficient (lo

by sauwan 5y ago

The round trip efficiencies for these compressed air storage have typically been terrible (<50%). That's mostly because compressing air is super inefficient (lots of wasted heat). Are they able to harness that waste heat in some productive way? ETA: Just saw the video. Looks like they store the heat to boost generation on the return trip. This [1] says they get ~60% efficiency. [1] https://www.inceptivemind.com/hydrostor-build-largest-compressed-air-energy-storage-system-california/18798/ https://www.inceptivemind.com/hydrostor-build-largest-compre...

arnaudsm 5y ago
60% is great! That's much better than hydrogen, but still far from lithium. Let's hope the $/kWh is decent.
- danans 5y ago
  It's not quite lithium ion efficiency, but it serves a different duration energy storage market (up to 24 hours vs single hours for lithium ion battery storage), and it has a much longer service life (50 years), so the levelized cost of storage might be lower than lithium ion battery storage.
  - sokoloff 5y ago
    The lithium ion batteries in my car store energy for weeks on end with losses around 1-2% per week (after an initial couple percent rapid drop).
    - danans 5y ago
      What I meant is that current grid scale lithium ion battery storage projects are designed for at maximum a few hours between charge and discharge. They are mostly for shorter window grid stabilization, not to store energy for days or weeks. LiIon grid scale batteries are still very expensive as a long term energy storage solution, they are sized to provide higher value grid ancillary services, like frequence regulation.
- thehappypm 5y ago
  Especially when you consider that the use case here is surplus energy, like when the wind is blowing harder than can be consumed. Efficiency might not be so important if you’re buying free wind or solar energy, as long as it’s above some minimum threshold. 60% feels pretty good.

by sauwan 5y ago

arnaudsm 5y ago

60% is great! That's much better than hydrogen, but still far from lithium. Let's hope the $/kWh is decent.

danans 5y ago
It's not quite lithium ion efficiency, but it serves a different duration energy storage market (up to 24 hours vs single hours for lithium ion battery storage), and it has a much longer service life (50 years), so the levelized cost of storage might be lower than lithium ion battery storage.
- sokoloff 5y ago
  The lithium ion batteries in my car store energy for weeks on end with losses around 1-2% per week (after an initial couple percent rapid drop).
  - danans 5y ago
    What I meant is that current grid scale lithium ion battery storage projects are designed for at maximum a few hours between charge and discharge. They are mostly for shorter window grid stabilization, not to store energy for days or weeks. LiIon grid scale batteries are still very expensive as a long term energy storage solution, they are sized to provide higher value grid ancillary services, like frequence regulation.
thehappypm 5y ago
Especially when you consider that the use case here is surplus energy, like when the wind is blowing harder than can be consumed. Efficiency might not be so important if you’re buying free wind or solar energy, as long as it’s above some minimum threshold. 60% feels pretty good.