The Natural Philosopher wrote:

Dave W wrote:

The unit is watt-hours, not watts per hour which doesn't make sense.

It does. Its the ramp rate of a power source or sink.
I.e. in the UK when the sun rises on a sunny summers day the power
output of all thjose solar panels rises at a peak of about 3GW per hour..

Or Dinorwig starting from zero (actually a small negative power when
spinning in air) to full output = 0.4 TW/h

Shame it can't keep that up for more than 16 seconds ...