Reply #47: When I do this calculation, I multiply...

[NNadir]

...86,400 sec-day^-1*365.25 days-year^-1 to get 31,557,600 sec-yr^-1.

If you operate any power source, like say a nuclear power plant, continuously, you can multiply the power times the time to get the energy.

This gives the energy produced. An exajoule is 10¹⁸J.

Most nuclear plants do operate near capacity, producing energy continuously at high power for periods that run about a year and a half, after which they must shut for refueling, which can take several weeks. Many times in nuclear calculations but not all, I insert the 90% capacity figure to reflect losses in fueling time.

Solar stations and wind stations that rate themselves in "watts" are almost always speaking of peak watts, the highest output they achieve under ideal conditions. Unlike a nuclear plant their capacity is not just 31,557,600 sec-yr^-1 times their "watt" rating, but also by a measured capacity factor that depends on their type and location. Very rarely are such capacity factors above 25%, because of the intervention of weather and, in the solar case, clouds and night. When I am in an especially generous mood, I insert 0.30 as a capacity factor, although very few solar stations ever achieve that number over a year of operation.

Thanks for asking.