kW, kW * h and kW / h

I saw (again / again / once again) the expression “5 MW of energy” in one of the recent articles and decided that it was time to briefly repeat how the kW differs from kWh.

Energy

From the point of view of a banal energy energy - this is the matter that is produced by the power plant, is stored in the battery and spent light bulbs.

Power

Power - the speed of movement or energy conversion. This is the amount of energy transferred or converted into a unit of time.

kw
Unit of power .
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kWh
A unit of energy - not a system, but the main in everyday life. As can be seen from the record, it is obtained by multiplying the unit of power (kW) per unit time (h).

Example 1
You have 2 heaters, 1 kW each. You bask about them for 1 hour. Electricity by 4 rubles per kWh

2 * 1 kW * 1 h * 4 rub / [kW * h] = 2 [kW * h] * 4 rub / [kW * h] = 8 rub

Example 2
You have 1 1 kW heater. You bask on it for 2 hours. Electricity by 4 rubles per kWh

1 * 1 kW * 2 h * 4 rub / [kW * h] = 2 [kW * h] * 4 rub / [kW * h] = 8 rub

Pay attention to the arithmetic of units of measurement. It is in it that the physical meaning of the calculations lies.

kWh = [kWh]
[kW * h] / [kW * h] = 1
[kW * h] * rub / [kW * h] = rub * 1 = rub

[kWh] + [kWh] = [kWh]

kW / h
kWh per hour - a unit of construction of power plants . The main characteristic of the power plant is its installed capacity (kW). The total number of power plants built in some time divided by this time (h) is the construction speed (kW / h). In practice, a multiple of it is used - MW / year.

If your text is not dedicated to macroeconomic indicators, then kWh (as well as kWh per hour) should not appear in it.

Capitalization

Once again, look at the unit of energy: kW * h .

k - decimal prefix "kilo" (small "k"). Decimal prefixes are case-sensitive and pressing SHIFT at the wrong time can lead to a billion times more error. Fortunately, at the moment there is no decimal prefix "K" (except for binary K = 1024).
Watt - short for Watt. It is written with a capital letter, like all names.
h - the usual unit. It is written with a small letter.

The theme, of course, looks childish against the background of the “Myths of modern popular physics”, but sometimes it is necessary to deal with the basics.