The emission reduction capacity and cost-effectiveness of Carbon Capture and Utilization (CCU) technologies are key factors influencing their development and deployment. This paper proposes a scientific framework to quantify the emission reductions, costs, and benefits associated with CCU technologies, applying it to four typical CCU technologies for analysis. The results show that for CO₂-enhanced oil recovery (CO₂-EOR), under different injection-to-production ratios, the emission reduction per unit ranges from 1.62 to 4.23 tCO₂/t of oil, with a levelized emission reduction cost of 388–883 CNY/tCO₂ and a gross margin of 0% to 55%. Higher injection-to-production ratios may lead to net permanent emission reductions. For CO₂-to-methanol production using green hydrogen, the emission reduction per unit is 4.89 tCO₂/t of methanol, with a levelized reduction cost of 632–1242 CNY/tCO₂. A subsidy of 18–833 CNY/tCO₂ is still required per ton of methanol for breakeven. The CO₂ carbonation of steel slag for construction materials offers a reduction of 0.94 tCO₂/t of slag, with a levelized cost of 219 CNY/tCO₂ and a gross margin of 14%–43%. Finally, the CO₂ cultivation of microalgae for biodiesel production results in a reduction of 0.36 tCO₂/t of algae, with a significantly high cost of 80,000 CNY/tCO₂ and a gross margin of 28%–52%. As a potential pathway for emission reduction, CCU technologies provide both environmental benefits and economic potential. The methodology presented in this paper offers valuable insights for further research in this area.

Carbon Capture and Utilization, CCU, Emission Reduction, Cost-effectiveness