China Primary Aluminum: The 45 Mt Ceiling, Power Shift, and Post-Rebate Export Economics

China's primary aluminum sector reached a structural inflection in late 2024 and 2025: output pressed against the nominal 45-million-tonne ceiling, the government removed the 13% export rebate on aluminum semis effective December 2024, and alumina prices swung from record highs to a slump that briefly left much of the smelter base loss-making. Provincial power is bifurcating the cost curve, with hydro-dependent Yunnan exposed to dry-season curtailment while Inner Mongolia shifts a coal base toward wind and solar to defend low power costs. This report sets out the conditions governing Chinese smelter profitability, the credibility of the capacity ceiling as a binding supply constraint, and the net effect of rebate removal on roughly 5 million tonnes of annual semi-fabricate exports.