Parthian battery, section view
original posted Jul.15.2017
As everyone knows, renewable energy sources like solar and wind are intermittent. To operate around the clock, some kind of high capacity storage is required, unless you employ heat engines to run backup. In this post, we will be exploring some of the possibilities.
Chemical Storage
One of the byproducts of desalination of seawater is salt, NaCl. A growing desalination industry means there will be more salt than anyone knows what to do with it. What if it could be used in batteries? NaCl industrial scale battery
wikipedia goes into more detail
Molten salt batteries, in general
Lithium may become obsolete as sodium has the supply advantage.
The sodium ion battery: the good and bad 3 min
Sodium Metal Battery: Better than Sodium-Ion, Better than Lithium-Ion 5 min.
New 'Perfect' Battery 4 min.
There is plenty of active research happening in the design of batteries, as the energy storage problem is a famous idea.
MIT News reports on chem/therm material
MIT News reports on molten metal battery for the grid
Zeolite thermal storage retains heat indefinitely, absorbs four times more heat than water
New technique stores summer heat until it's needed in winter
Edit, thnx to u/AllThat5634
battery history
Low-cost saltwater battery wins $500,000 award
BBC report NanoFlowcell Quantino
Electric Power Is About to Change Forever | Bloomberg 4 min.
Electronic Storage
The capacitor, or condenser, is an electronic component that stores electric charge on conductive plates separated by a "dielectric" (non conductive material with special properties). Electric charge is a fundamental force of nature, we see it in lightning discharges and after you rub on a fabric then touch a metal object. Most capacitors used in electronic devices can't store much energy, but the principle can be scaled up and otherwise enhanced until you have a "supercapacitor" How good are they?
Mechanical Storage: Flywheel
what wikipedia says about it
Scientific American reports on new development
In cars and trucks
VYCON® Direct Connect
Thermal Storage
With some solar farms not using photo voltaic cells, but concentrated light to heat a receiver, storing heat is the obvious opportunity. This is an old idea. Before mechanical refrigeration, there was a rural industry in which ice from frozen lakes was cut into blocks, and stored in large sheds insulated with sawdust.
Scientific American report, Germany
Discovery of a 'heat-storage ceramic'
Pumped Heat Electrical Storage
MOLTEN SALT ENERGY STORAGE
Pumped Hydro Storage
Wikipedia article on this is good.
Reading the previous article, there is a discussion of submarine reservoirs for storage. This concept is interesting, but the sketchy description leaves me to conclude that the plan includes spheres of 30m diameter (about 100 ft) capable of holding a vacuum 700m beneath the surface. That would be QUITE a big ball. It gave me another idea, a tethered sphere, with a cable attached to a pulley block, the tension in the cable to be wrapped around a shaft with a gear-up to a generator. The ball is lowered against buoyancy with energy input, released slowly for energy output. Patent: Buoyancy energy storage and energy generation system I just reinvented this as an offhand idea (July14,2017).
In places where reservoir evaporation is high, losses can be reduced with plastic shade-balls.
Compressed Air Storage
I did not know this was a big deal until I started writing this report. I was thinking of doing it on a small scale with a wind turbine compressing air to power a water-well pump, but this is something else.
On a smaller scale, starting engines is done with compressed air.
LightSail® Energy
Tunnels for air chambers | ColdFusionTV 11 min.
sequel: Overview of Battery Tech
there doesn't seem to be anything here