how to conceptualize energy units generated, distributed, and eventually used by loads throughout electricity grids (e.g. gigawatt, megawatt, megawatt-hours, kilowatt, kilowatt-hours, etc.)
In: Physics
So, for starters most of what you’re asking for are units of **power**, not energy. Gigawatts, megawatts, and kilowatts are just rates of power production or usage, equivalent to one gigajoule per second, one megajoule per second, and one kilojoule per second.
A few watts will power a night light.
A kilowatt (1,000 watts) will power an electric kettle or microwave oven.
A megawatt (1,000,000 watts) will be the regular output of a standard-sized wind turbine.
A gigawatt (1,000,000,000 watts) will be about half of the peak power outputs of the Hoover or Aswan Dams.
For the others (watt-hours, kilowatt-hours, etc.), those are units of *energy* (no different than joules), but are given in the industry standard units of watt-hours (so, 3600 joules) for various reasons (basically engineering, accounting, emissions, and regulation stuff).
A watt-hour is comparable to the energy of a gram of TNT.
A kilowatt-hour is actually comparable to the caloric value of three snickers bars.
A megawatt-hour is around the value of the energy expended by your heart over 80 years, or the total energy contained within the fuel in the gastank of a normal-sized car.
A gigawatt-hour is the amount of energy contained in the fuel tanks of a large aircraft (think an Airbus A330).
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