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▲ gertrunde 5 hours ago

Sort of neither?

It's 30kW for one hour.

(Or 1.25kW for 24 hours, or however you prefer).

[Link: https://en.wikipedia.org/wiki/Kilowatt-hour]

▲numpad0 3 hours ago | parent | next [-]

It's like you had a faucet with cross section of 2 square inches, and 15 seconds with that faucet wide open would fill a jug. That jug holds 30 squareinches-seconds of water.

You may then use that water over the course of a day. That's 30 sqin-sec per day. That is not 30 square inches for a whole day. It's second per day.

Or watt hour per week or whatever.

Yes, it can be described like 0.00034722 sqin/day, and that corresponds to no physical object and that would be largely useless.

Why not Joules or Liters? Because that's complicated for anything electrical.

▲OJFord 5 hours ago | parent | prev [-]

Pretty sure GP understands that, their point being you can't just wave away 'per unit time' when talking about it relative to generation, it matters.

▲buran77 5 hours ago | parent | next [-]

"30kW per day" makes no sense. It's like saying "100km/h per day". W is a unit of power, Wh is a unit of energy.

It's unintuitive because a guy named Watt decided "Joule per second" is Watt, so the intuitive units Joule and Joule per second got turned on their head to W times hour and Watt. This is opposite to usual intuition of distance and speed for example, km and km/h. If I redefined the km/h to a "tick", then a km would become "tick times hour".

If you want a "better than nothing" but imperfect analogy, Wh is how much water you have in a bottle, and W is how quickly you can get the water out.

▲SamBam 5 hours ago | parent | prev [-]

"30kWh per day" isn't waving away anything.

30kW is a rate.

30kWh is a measure of energy, about 100MJ.

30kWh/day is a rate again, 100MJ/day.

It seems clunky, but it's a way energy usage in a house is typically measured.