Integration of Thermal Solar Power in an Existing Combined Cycle for a Reduction in Carbon Emissions and the Maximization of Cycle Efficiency

The energy transition towards renewable energy sources is vital for handling climate change, air pollution, and health-related problems. However, fossil fuels are still used worldwide as the main source for electricity generation. This work aims to contribute to the energy transition by exploring the best options for integrating a solar field within a combined cycle power plant. Different integration positions at the gas and steam cycles for the solar field were studied and compared under several operating conditions using a thermodynamic model implemented in MATLAB R2024a. Fuel-saving and power-boosting (flowrate and parameter boosting) strategies were studied. The results revealed that, for a maximum fuel savings of 7.97%, the best option was to integrate the field into the steam cycle before the economizer stage. With an integrated solar thermal power of 3 MW, carbon dioxide emissions from fuel combustion were reduced to 8.3 g/kWh. On the other hand, to maximize power plant generation, the best option was to integrate the field before the superheater, increasing power generation by 24.2% for a solar thermal power of 4 MW. To conclude, guidelines to select the best integration option depending on the desired outcome are provided.