Bi-objective Optimization of a Combined Cycle Power Plant with Economic and Life Cycle Assessment Considerations

Abstract

The demand for electricity has increased worldwide and concerns about cost and environmental impact regarding electric power generation have increased as well. Combined cycle power plants are used worldwide to meet that demand. In this paper, a methodology for the cost and environmental impact bi-objective optimization of a combined cycle power plant using a life cycle assessment indicator is proposed. Eco-indicator 99 is used, but other indicators can be used as well. A genetic algorithm is used to solve the formulated optimization problem. A sensitivity analysis is done regarding the key parameters of the plant. The novelty of this paper is the application of a life cycle assessment of fuel, equipment and emissions, and a cost estimate in the formulation of the optimization problem. This methodology can be applied for preliminary feasibility studies of combined cycle power plants in light of both cost and environmental impact simultaneously. Results show that, according to the Pareto front, the levelized cost of electricity ranges from $ 41.1 to 46.2 per MWh, and the environmental impact of electricity ranges from 27.5 to 28.8 mPts per kWh. In addition, one must consider the environmental impact of the fuel in modeling; i.e., the environmental impact of emissions only is insufficient to model and assess the plant fairly. Moreover, the levelized cost of electricity is sensitive to the fuel cost and the environmental impact of electricity is sensitive to the fuel’s environmental impact.