Crit­i­cal assess­ment of mega-projects is emerg­ing as a much-need­ed dis­ci­pline in an era when, in many places, resource demands exceed envi­ron­men­tal capac­i­ty. This tech­no-eco­nom­ic study, using the Desali­na­tion Eco­nom­ic Eval­u­a­tion Pro­gram devel­oped by the Inter­na­tion­al Atom­ic Ener­gy Agency, shows that by 2030, Chi­na will have the capac­i­ty to pro­duce 23.1 bil­lion m3 of water annu­al­ly, at $0.86/m3, as a co-prod­uct of elec­tric­i­ty gen­er­a­tion through nuclear pow­er, pro­vid­ed that the coun­try favors desali­na­tion over water diver­sion. We cal­cu­late that the result­ing water pro­duc­tion and sup­ply chain need­ed to erad­i­cate absolute scarci­ty for 0.16 bil­lion peo­ple will cost between $0.99/m3 and $1.79/m3, and we prove that this will be afford­able, even for the poor­est  inhab­i­tants. We then com­pare both coal and nuclear desali­na­tion with the cur­rent­ly planned South–North Water Trans­fer Mega-Project and show that, while the short-run cost of water diver­sion is low­er, crit­i­cal vul­ner­a­bil­i­ties and future resource demands favor nuclear desalination.