Electric energy is sold by the kilowatt hour (kWh). A kilowatt is a unit of power. A kilowatt hour is a unit of energy. It's the sum of power consumption over a given period in hours.
As in example, saying a motor consumes 100 kW and runs for 20 hours or 2000 kWh
A kilowatt per hour (kW/h) I think it gives the average power.
For the same above example it would be 5 kW/h.
What do you think?
Power is the rate at which you consume energy.
It can be regarded as analogous to physical speed (metres per second).
Physical speed is the rate at which you "consume" distance.
If you wanted to work out what speed per second is, that equates to acceleration so, in electrical terms, watts per second is how quickly the power consumption increases (or decreases) over time and, can be meaningful in some analyses.
It's not a precise analogy but, it works for me.
1 kilowatt = 1 kilojoule/second (1 kW = 1 kJ/s). The dimension of time is already taken into account in the definition of the watt.
1 kWh = 1 kW × 3600 s = 1 kJ/s × 3600 s = 3600 kJ. (The 'second' units have cancelled out.)
"kW/h", therefore, can only refer to a rate of change of power. The only sensible use I can think of would be something like, "The load was 100 kW initially but decreased at 5 kW/h."
Figure 1. Energy is power by time. The average power is measured in units of power (W), not watts/hour.
Average power is just total energy consumed divided by time and is measured in W or kW.
It doesn't matter what we think. Just use the definitions and the units properly.
If you want average power, then that's energy per unit time. It would therefore be kWh/h, and cancelling h above and below gives kW.
Power, instantaneous power, average power, all have the same dimensions, power, kW.
No ... the average power is simply 100kW in your example.
If the motor ran for every second hour for 10 hours total in that 20 hour period, it would use 1000 kWh, and the average power would be 50kW.
The only sane use of kW/hour is to measure the capacity of a solar cell manufacturing plant. If, in an 8 hour shift, it can manufacture enough solar cells to generate 40kW, then its capacity is 5 kW/h.
As Andy says, this is like an acceleration, as the size of the solar farm gets bigger every hour and it generates more power.
