Hydropower in green aluminium production: why it still dominates over solar and wind

Green aluminium production relies heavily on hydropower because smelting requires continuous, dispatchable electricity that solar and wind cannot yet provide at scale. While solar has more than double the global installed capacity of hydropower, hydropower supplies 34 to 39 percent of the energy used in aluminium production worldwide. The reason is the capacity factor gap: large hydro facilities run at 40 to 60 percent capacity or higher, while solar typically achieves only 15 to 25 percent under real conditions. Switching from coal to hydropower cuts the carbon footprint of aluminium smelting by roughly 75 to 80 percent, from about 20 kg of CO2 per kg of aluminium down to around 4 kg. Norway, Russia, Canada, Iceland, and Brazil are the main production hubs because they have large hydro resources. The article also notes that green aluminium claims remain inconsistent without a binding global standard, and that full decarbonization requires tackling upstream refining and recycling alongside electricity sourcing.