Comment on China connects its largest battery-supercapacitor hybrid storage plant - Energy Storage
RvTV95XBeo@sh.itjust.works 5 days ago
Supercapacitors provide ultrafast response times – specified at 0.001 seconds – and maintain over 85% capacity at –40°C, significantly outperforming lithium-ion batteries in extreme cold.
Outperform how? At being a capacitor? That’s their whole point.
On the energy side, 85% of 29 MW-min is 0.41 MWh. Even if the batteries lose 99% of their capacity at -40 °F, last I checked .42 MWh > 0.41 MWh.
These are two different tools for two different purposes, I’m not sure how you compare their “performance” under this metric.
Batteries and capacitors both store electrical potential, but in different ways. So yes you can compare their performance at storing and then delivering electricity under specified conditions.
Batteries can keep charge longer with less loss, but capacitors are faster at responding to rapid changes in eletrical supply and demand.
The quote you included shows exactly how they compared the performance at low temperatures, as an example. Maybe I am missing your objection?
A capacitor has ~1% of the storage capacity of a battery of similar power rating.
Saying its storage performance is better because its holds a larger % of that capacity at low temperatures is nonsense because its storage performance objectively sucks (and not what it’s designed to be good at)
It’s like saying a Tesla is better than a 747 because it can go from 0-60 faster. A technically true statement but a meaningless performance comparison.
The caps also average charge fluctuating in the batteries, which should significantly enhance the cell lifespan.
eleitl@lemmy.zip 5 days ago
Supercapacitors are for stabilizing the grid, the batteries are for flattening the peaks/load-levelling at diurnal scale.