Short-Term Optimization of a Combined Cycle Power Plant Integrated With an Inlet Conditioning Unit

Abstract

Under new scenarios with high shares of renewable electricity, combined cycle gas turbines (CCGTs) are required to improve their flexibility to help balance the power system. Simultaneously, liberalization of electricity markets and the complexity of its hourly price dynamics are affecting the CCGT profitability, leading the need for optimizing its operation. An inlet conditioning unit (ICU) offers the benefit of power augmentation and “minimum environmental load” (MEL) reduction by controlling the gas turbine (GT) inlet temperature using cold thermal energy storage (TES) and a heat pump (HP). Consequently, an evaluation of a CCGT integrated with this unit including a day-ahead optimized operation strategy was developed in this study. To establish the hourly dispatch of the power plant and the operation mode of the ICU, a mixed-integer linear programing (MILP) optimization was formulated, aiming to maximize the operational profit of the plant within a 24 h horizon. To assess the impact of the unit operating under this dispatch strategy, historical data have been used to perform annual simulations of a reference power plant located in Turin, Italy. Results indicate that the power plant's operational profit increases by achieving a wider operational range during peak and off-peak periods. For the specific case study, it is estimated that the net present value (NPV) of the CCGT integrated with the ICU is 0.5% higher than the CCGT without it. Results also show that the unit reduces the MEL by approximately 1.34% and can increase the net power output by 0.17% annually.