Availability and Capacity Factor image
Availability of a power is the percentage of the year that the plant produces electricity. Availability is equivalent to the capacity factor commonly used for other technologies. For wind, solar and hydro weather losses are compounded with technology losses.

In some places, availability has been called the Achilles' Heel of Fusion. The page on this website, Maintenance, Breakdowns and Availability, discusses the availability of fusion power plants.