The article makes the common (and grating) error of conflating power (1.5 gigawatts) and energy (power over time). Put another way, "1.5 gigawatts" does not in any way describe a rate. Do they mean 1.5 gigawatts per hour? or per day? or per year? I'm referring to this section: ...the rate that energy builds below the volcano is only around 1.5 gigawatts - less heat than a typical power plant sheds. Yellowstone curren…
Gigawatts is a rate, which gets multiplied by an amount of time to measure an amount of energy. That's why your energy bill is based on kilowatt-hours. If you have a device that consumes power at a rate of one kilowatt (say a toaster oven) and you run it for one hour, that's one kilowatt-hour (kWh) of energy.
1 Watt (unit of power) is 1 Joule (unit of energy) per second. So "1 Watt-second" is just a needlessly-long way of saying "1 Joule".
Instead of using the idiotic kW-h units, they should just use kJ. (1 kW-h = 3600 kJ or 3.6MJ.)