Temperature-dependent performance of CCGTs: Unit commitment analysis

• Published in: Energy (Oxford) 2025-03, Vol.318, p.134680, Article 134680
• Main Authors: Mokhtari, Ali, Latify, Mohammad Amin, Zakeri, Yadollah
• Format: Article
• Language: English
• Subjects: Ambient temperature effects; Combined cycle gas turbine; Unit commitment
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2025.134680

The growing emphasis on environmental sustainability underscores the need for cleaner and more efficient energy sources. Combined cycle gas turbines (CCGTs) play a pivotal role in this transition due to their high efficiency, operational flexibility, and lower emissions. As CCGT penetration increases, accurately modeling their performance becomes critical for reliable power system operation. Ambient temperature is one of the key parameters that significantly influences CCGT performance. This paper investigates the impact of temperature-dependent CCGT performance on the unit commitment (UC) problem, emphasizing the influence of ambient temperature across different operating states. Detailed plant models for CCGTs are developed using Thermoflow GT PRO with practical unit data, analyzing various operating states and temperature conditions. Temperature-dependent correction factors for maximum power output and heat rate, representing relative changes from design conditions, are derived. These factors are embedded into a configuration-based CCGT model within a mixed-integer linear programming (MILP) UC formulation to capture performance variations caused by ambient temperature fluctuations. Five case studies analyze: (1) the consequences of neglecting ambient temperature; (2) the value of temperature forecasting; (3) long-term temperature effects; (4) the influence of CCGT penetration levels; and (5) simultaneous variations in load and temperature. Results show that neglecting temperature can significantly misestimate CCGT capacity, potentially causing supply reliability issues during high-temperature periods. The value and accuracy of temperature forecasting are evaluated. Long-term simulations reveal substantial temperature effects on system operation, while reduced CCGT penetration lessens temperature impacts on reliability and costs. Analyzing simultaneous load and temperature variations provides further insights into realistic system behavior. By quantifying the impact of temperature-dependent CCGT performance on UC decisions, this study provides actionable insights for power system operators, particularly in systems with high CCGT penetration. [Display omitted] •Detailed CCGT plant models account for temperature-dependent performance.•Correction factors integrate into the UC with configuration-based CCGT model.•Neglecting temperature causes load shedding, higher costs, and capacity errors.•Higher CCGT penetration worsens temperature-related issues.