Re:To Store Renewable Energy, Try Freezing Air
by aurizon on Wednesday January 08, 2020 @09:38PM
(#21998036)
Yes, pump motors and generators.
so 96% motor and 96% pump up = are in the 95-7% efficiency, pumps about the same up or down.
So .96 x .96(up) and .96 x .96 (down) = 84.9% and friction drops that a little. It is quite good if you hacve a handy high dam pond to use as many places do. To build a high dsm pong may not be economic unless you have a topographic valley you can dam and fill (and murder all the locals and flying snapping turtles) Dams have many objectors, so new ones are hard to build, except for China.
Re:To Store Renewable Energy, Try Freezing Air
by natmaka on Thursday January 09, 2020 @12:53AM
(#21998869)
The 'concrete'-based approach (gravity storage) is pursued, for example by a firm named Heindl Energy https://heindl-energy.com/
There are offerings and deployed energy-storage systems based upon flywheels https://en.wikipedia.org/wiki/Flywheel_energy_storage
Re:To Store Renewable Energy, Try Freezing Air
by nine_k on Wednesday January 08, 2020 @08:15PM
(#21997568)
Motors efficiency, an generators efficiency, can easily be 0.95, and even 0.98.
So overall the lift approach must be pretty efficient, even when we subtract losses for friction in the rope and of the air.
The energy density isn't great, though, you need really much mass, and large elevations, to store anything interesting.
Pumping large amounts of water uphill is more feasible, even if less efficient, and is actually done.
I'd be super interested to see an efficiency comparison between the frozen air approach and the "concrete (or any other cheap, heavy thing) battery approach" For the uninitiated: the process of using excess energy to drive motors to lift/stack heavy objects tethered to a pulley. Consuming that energy is by slowly lowering them down as they drive an engine/turbine.
As a rider, I'd be equally interested in the realistic energy density between the two methods: how many MWH can you store per acre.
Thirdly, I would guess the concrete battery would require less maintenance--but I'd love to see a comparison of that too.
Thank you for your comment and getting me thinking about this.