In 2000 renewables (mainly solar, wind, geothermal, tidal, and biomass, but not hydroelectric) accounted for about 1.4 percent of global electricity generation.[224] By 2021 it had risen to 12.85 percent, for an average doubling time of about 6.5 years during that span.[225] Doubling is faster in absolute terms, since the total amount of power generation is itself growing—from the equivalent of about 218 terawatt-hours in 2000 to 3,657 terawatt-hours in 2021, with a doubling time of around 5.2 years.[226]
