6 ms·
While it is appealing compared to many alternatives and is more portable for smaller settings, when used on an industrial scale like this giant battery, I wonde
by lend000 6y ago
While it is appealing compared to many alternatives and is more portable for smaller settings, when used on an industrial scale like this giant battery, I wonder how it compares in overall utility to gravity batteries [0].
The nice thing about gravity batteries is that they can form a closed loop with water supply, too, pumping reclaimed water back up into reservoirs when there's excess power. I'd expect compressed air to have much higher energy density, but it would be interesting to see if anyone has the numbers.
[0] https://en.wikipedia.org/wiki/Gravity_battery https://en.wikipedia.org/wiki/Gravity_battery
- sa1 6y agoIn my country, there are economic challenges: water isn't available everywhere, diverting water is not cheap, and it messes with water sharing agreements, which are a political issue in themselves.
- toomuchtodo 6y agoAs I once heard from a Wyoming rancher, “Whiskey’s for drinking, water’s for fighting.” Water rights are treacherous to navigate.
- PopeDotNinja 6y agoIt’s gonna get worse, too, with upstream countries building dams at the expense of downstream countries.
- luma 6y agoGravity batteries only need mass, it needn’t be water: https://youtu.be/gn5AM75AGvw https://youtu.be/gn5AM75AGvw
- ashtonkem 6y agoPumped water batteries are geographically limited, since they can basically only be installed wherever you could build a dam anyways.
- trickstra 6y agoYes, but you can be moving rocks up a hill on a train or cable car. Or concrete blocks up a crane. Geographic limitation solved.
- ashtonkem 6y agoRocks and hills are equally geographically limited. Cranes would work, but I think you’re ignoring the massive difference in mass between what the biggest cranes in the world can lift and even the smallest reservoir.
- walrus01 6y agosome people are trying this: https://qz.com/1355672/stacking-concrete-blocks-is-a-surprisingly-efficient-way-to-store-energy/ https://qz.com/1355672/stacking-concrete-blocks-is-a-surpris... I believe there's a beta test facility under construction now.
- arethuza 6y agoStill pretty small compared to pumped storage - they give a value of 20 megawatt-hours, the Cruachan pumped storage scheme (which isn't particularly large) stores 7.1 gigawatt hours: https://en.wikipedia.org/wiki/Cruachan_Power_Station https://en.wikipedia.org/wiki/Cruachan_Power_Station
- newyankee 6y ago
- gnramires 6y agoThose methods are actually quite similar, they're all ultimately related (limited by) tensile strength of materials. So costs and specific energy densities (per construction material unit) are similar. An important figure is cost/tensile strenght I guess. (Compressed air: limited by container tensile strength; gravity batteries: limited by strength of cables) I suspect even the constants involved are the same (given the materials are almost uniformly under nominal load), although I don't have time to investigate right now (a good curiosity research topic!).
- istjohn 6y agoThey are storing liquid air at low pressure, so container tensile strength is not a limiting factor at all.
- trickstra 6y agoI believe these ones are not limited by tensile strength: https://interestingengineering.com/concrete-gravity-trains-may-solve-energy-storage-problem/ https://interestingengineering.com/concrete-gravity-trains-m.... They are a bit limited by available geography, but far less than say pumped hydro.
- gnramires 6y agoIndeed! In this case it's the integrity and friction of the soil (of the hill) that's keeping the potential energy contained, and this hill soil is "free".
- disambiguation 6y agolook into energy stored on energy invested https://en.wikipedia.org/wiki/Energy_return_on_investment#ESOEI https://en.wikipedia.org/wiki/Energy_return_on_investment#ES... according to the wiki, pumped hydroelectric storage has a ratio of 704 where as compressed air energy storage has a ratio of 792.