Exergoeconomic and exergoenvironmental analyses of the AZEP concept, a combined cycle power plant with CO2 capture

CO2 capture and storage from energy conversion systems is widely known as a potential method to reduce CO2 emissions to the atmosphere and to limit the impact of energy use on the climate. This study provides an evaluation from an economic and environmental point of view of the Advanced Zero Emission Plant (AZEP), an oxy-fuel concept. The plant is evaluated and compared to a reference plant that includes no CO2 capture. The concept appears to have relatively lower cost and exergy expenditures than competitive alternatives, like CO2 capture with post-combustion technology. Two exergy-based methods, the exergoeconomic and the exergoenvironmental analyses, are used to determine the environmental and economic impacts, respectively, and options to improve the overall effectiveness of the plant. The results of the detailed exergoeconomic and exergoenvironmental analyses are compared to those of the reference case. The exergoeconomic analysis shows a high increase in the costs due to the introduction of the new technology used in the AZEP. On the other hand, the additional cost is counter-balanced by the reduced environmental impact of the plant with CO2 capture. The applied exergy-based methods provide a way to suggest changes to the structure and the operation of the plants.