Comparison of CO 2 Emission Reduction Performance of Three Production Models Using Coal Fly Ash from Coal-Fired Power Plants in Vietnam

This study evaluates the CO 2 emission reduction performance of Coal fly ash (CFA) utilization models currently implemented at coal-fired power plants in Quang Ninh province, northern Vietnam. CFA is applied through three utilization models, including blended Portland cement production, concrete mixing, and non-fired brick production. The assessment framework integrates Life Cycle Assessment methodology with greenhouse gas inventory approaches recommended by the Intergovernmental Panel on Climate Change (IPCC), with system boundaries defined under Vietnamese production conditions. The results show that the utilization of CFA significantly reduces CO 2 emissions by replacing high-carbon conventional materials such as clinker and Portland cement, while simultaneously eliminating the firing stage in brick production. The calculated net emission reduction efficiencies reach approximately 0.885 tCO 2 per tonne of CFA for the cement model; 0.915 tCO 2 per tonne of CFA for the concrete model; and 0.643 tCO 2 per tonne of CFA for the non-fired brick model. Among the studied scenarios, clinker substitution in cement production demonstrates the highest emission reduction potential due to the direct avoidance of calcination-related emissions. Meanwhile, the non-fired brick model shows the highest emission reduction per unit product owing to the elimination of kiln combustion. These findings also confirm that a combined deployment of CFA utilization models offers a robust strategy for mitigating greenhouse gas emissions, advancing circular economy principles, and accelerating the transition toward low-carbon construction materials in Vietnam.