Overcoming the high-cost barrier of sustainable aviation fuel in China: A study on HEFA and ATJ deployment driven by carbon targets using learning curve and nonlinear programming

The high cost of sustainable aviation fuels (SAF) hinders widespread adoption. This study develops a deployment framework for China that integrates learning curves and non-linear programming to quantify economies of scale and identify cost-breakthrough pathways. Focusing on HEFA (from waste oils) and ATJ (from cellulosic ethanol), the model optimizes technology selection under carbon targets. Feedstock costs dominate both HEFA (87.3%) and ATJ (92.8%). While ATJ has higher initial costs, its steeper learning curve makes it more competitive above 4.654 million tons annually. Under a breakthrough scenario, HEFA-SAF initially leads, but ATJ-SAF becomes dominant by 2038 (carbon neutrality, 94% share) or 2034 (net-zero, 87.8% share), reaching a 1:1 ratio by 2050. Meeting China's carbon neutrality target (91% SAF penetration) would reduce aviation emissions to 136 million tons by 2050. SAF achieves cost competitiveness by 2036 (carbon neutrality) or 2034 (net-zero), with costs falling below $0.66/kg by 2050. However, feedstock supply must increase 11.5-fold to realize this potential. The framework balances emissions and costs, emphasizing the need for strategic investment and policies to address feedstock constraints and advance SAF deployment in China.