The Energy Barrier

Desalinating one cubic meter of seawater requires about 3-4 kilowatt-hours of electricity. That sounds modest until you scale it to supply a city. A large desalination plant serving one million people consumes as much energy as a small power station generates.

That energy demand has fallen by over 80 percent since the 1970s and keeps dropping. Pairing desalination with renewable power is the obvious next step. Saudi Arabia's NEOM project plans solar-powered desalination, and Australia's Perth plant already runs largely on wind energy.