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Finnish City Inaugurates 1 MW/100 MWh Sand Battery

(cleantechnica.com)
190 points erwinmatijsen | 1 comments | 03 Sep 25 06:00 UTC | HN request time: 0.309s | source
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davedx ◴[03 Sep 25 10:20 UTC] No.45114117[source]▶
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?
replies(3): >>45114268 #>>45114558 #>>45115255 #
1. rsynnott ◴[03 Sep 25 13:06 UTC] No.45115255[source]▶
Watts and watt-hours are generally used internationally for heating; the Btu is largely a historical oddity in most places outside the US.

Also it is a mess, as is traditional for US customary units:

> A Btu was originally defined as the amount of heat required to raise the temperature of one pound of liquid water by one degree Fahrenheit at a constant pressure of one atmospheric unit. There are several different definitions of the Btu that differ slightly.

(Best one is still the fluid oz, tho. A US customary fluid oz is about 29.6ml, a US food labelling fluid oz is exactly 30ml.)