Finnish City Inaugurates 1 MW/100 MWh Sand Battery

Good idea but why is it being measured in MW/MWh when it’s not an electrical battery? I know they can be converted but maybe it should be measured in actual thermal units like Btu?

W and J are the SI units for power and energy. Those units make the most sense to use in Europe, regardless of the type of energy.

Wh is an abomination that has come about because professionals think consumer brains would expose if they ever saw the unit watt-seconds (J). No consumer had any preconceived notion of either Wh or J, so had we used J from the start, it wouldn't have been a problem...

(Yes, same with Ah vs C, though the battery pros also shot themselves in the foot by starting to use C (electrical charge) to mean "the capacity of this battery" when talking about charge rate, a.k.a. current.)

I dunno, 1kWh seems quite natural as a unit of building-scale energy usage when you know a kettle or space heater is about 3kW. We think about energy usage much more in terms of kW and hours than in watts and seconds. And even in small devices like an LED bulb, 5W is more obviously 0.005kW than, say, 2 hours is 7200 seconds.

And in this context it's much more obvious that it can notionally deliver energy at a peak rate of about 1% capacity per hour. If you said 1MW/360GJ, I don't think that would be nearly as clear.

Same for batteries, which started with car batteries/deep cycle batteries, rather than AA batteries, which usual don't even say, and phones. A battery that provides 1 amp (at 12V, but that's already given in a system) for 50 hours. Makes immediate practical sense, especially when equipment is often labelled in current draw and you can measure amps with an ammeter. 2.16MJ far less so.