There is no such thing as a "kilowatt per hour". Kilowatt is a unit of power, not of energy. A unit of energy is kilowatt-hour. That's kilowatt times hours, not "per" hour ("per" implies division, not multiplication). If a generator produces 10 kilowatts, that means it produces 10 kilowatt-hours every hour.

It is a unit of energy. If energy is transferred at a rate (power) of one kilowatt, during one hour, then one kilowatt-hour (kilowatt times hour) of energy will be transferred. Since a joule is equal to a watt-second, a kilowatt-hour is the same as 3.6 million joules.

In North America it is kilowatt/hour. A kilowatt is 1000 watts. To find out how much your utility company charges you per kilowatt/hour, look on your utility bill. On my bill it is .08 cents for every kilowatt/hour that I consume.

Kilowatt is a measure of the rate of energy use. It is 1,000 Watts or 1,000 Joules per second. A kilowatt hour is 1,000 Joules per second for 3,600 seconds or 3,600,000 Joules. This means a Kilowatt hour not a rate but a measure of total energy used.