Decarbonization challenges and opportunities of power sector in Uzbekistan: A simulation of Turakurgan natural gas-fired combined cycle power plant with exhaust gas recirculation

Natural gas dependency on power generation in Uzbekistan is high, with more than 85% of electricity production coming from natural gas. Hence, natural gas-fired power plants constitute the largest proportion of greenhouse gas emissions. Carbon capture, storage, and utilization (CCSU) plays an essential role in reaching Uzbekistan’s reduction targets for carbon dioxide (CO₂) emissions. In this study, one (450 MW) of the two identical blocks of a 900 MW Turakurgan natural gas-fired combined cycle power plant (NGCCPP) located in the Fergana valley in Uzbekistan is simulated using Aspen Plus^® commercial software and validated with its open access project data prior to the evaluation of end-of-pipe CCSU unit integration. An optimal value of exhaust gas recirculation (EGR) is identified in order to further increase the CO₂ content in the flue gas while reducing the flue gas flow rate. In addition, according to the simulation results, around 2.4 Mt of annual CO₂ emissions can be avoided when the capture plant is set at a 90% CO₂ capture rate. Apart from that, the suitability of various CCSU integration methods such as absorption, adsorption, membrane separation, and CO₂ bio-fixation is discussed considering the power plant's site-specific conditions and the obtained flue gas stream characteristics.