definition
strict definition
energy
Measurements of energy handled by an object and the power at which it is produced or consumed.
Energy measurements describe amounts produced, transported, consumed, wasted, or otherwise handled by an object. Related power measurements describe the rate at which energy is handled.
An energy total covers an amount handled over a defined period, such as one year of electricity generation. Power describes the rate of production or consumption during operation.
The unit distinguishes the two quantities: kilowatt-hours measure electrical energy, while kilowatts measure power. A yearly energy total cannot be substituted for an operating power value.