Capacity factor means "take the amount of MWh actually produced by the plant, divide by the number of MWh that theoretically could be produced if it generated i

Capacity factor means "take the amount of MWh actually produced by the plant, divide by the number of MWh that theoretically could be produced if it generated its maximum output 24/7/365." 70GW of solar refers to the maximum instantaneous production (note that it is measured in GW not GWh). So while in full sun, all of that solar is generating 70GW of power per unit time but at night, it generates 0W. Average that over a year and it generated about 28% of it's maximum power over time. Hydro plants have huge ranges of capacity factors depending on other restrictions on the dam like if it is used for flood mitigation, if it is operated as a peaker plant, and if it snowed a lot the past winter. Nuclear Plants generally have capacity factors in the 90% range to account for swapping out fuel periodically. Fossil fuel plants have capacity factors of >90% unless they are used as peaker plants.