Efficiency evaluation of CO2 utilization technologies in China: A super-efficiency DEA analysis based on expert survey

As the largest coal consumer and leading CO2 emitter, China faces huge pressure on emission reduction and addressing climate change. Moreover, the feature of coal dominated energy constitute system determines that Carbon Capture, Utilization and Storage (CCUS) technology would be of vital importance for China, especially the CO2 utilization technology due to its benefit creating effect. While CO2 utilization technology in current China is still in juvenility and needs to be predictively evaluated. Thus, this paper aims to assess the potential efficiency of CO2 utilization technologies in China. First, two sets of index systems of efficiency evaluation are established, and each of which contains three input indicators and three output indicators. We then conduct the Data Envelopment Analysis (DEA) efficiency evaluation on 20 key CO2 utilization technologies, which are classified into three categories, i.e. chemical, biological and geological utilizations, using so-called CCR, BCC and SE-CCR DEA models respectively. The results show that: (1) CO2 utilization technologies receive different DEA scores, while that with score 1 or more are dominated by chemical utilization; (2) CO2 geological utilization exhibits relatively higher sore under the direct-emission-reduction scenario than it does under comprehensive-emission-reduction scenario; (3) there are significant differences among the four types of biological utilization technologies; (4) DEA efficiency performance of CO2 utilization technologies gain improvement in 2030 than that in 2020, which in part provide evidence for the rationality of our study; and (5) DEA score rank has no correlation with emission reduction. Finally, some policy implications are proposed.