Exergoeconomic Analysis of the Allam Cycle

Greenhouse gas emissions from fossil fuel combustion is one of the main causes of global warming. Carbon capture, storage, and/or utilization consists of technologies and measures focused on diminishing anthropogenic emission of carbon dioxide (CO2), an important contributor to the greenhouse effect. One of the most promising methods for carbon capture is oxy-combustion, for which several innovative alternatives have been proposed in recent years. This paper evaluates a thermodynamic cycle known as the Allam cycle. The novelty of this plant lies in the fact that the cycle uses supercritical CO2 as the working fluid of the process. The evaluation is performed using exergetic, economic, and exergoeconomic analyses. The election of an exergy-based methodology rather than a conventional energy-based analysis is motivated by the better characterization of the thermal system achieved by the first. The goal is to assess the cost effectiveness of the cycle and to determine a way to optimize it by design changes and other modifications. Overall, we find that the calculated efficiency and cost of electricity can compete with other low-emission technologies, but they are higher than those of the currently operating combined cycle plants.