Thermodynamic assessment of a combined-cycle power-plant with solar-assisted reheating

There are several advantages in the integration of solar energy into a fossil fuelled power-plant: reduced fuel input and emissions; the intermittency issue associated to solar energy, which often leads to expensive energy storage methods, can be easily accommodated by the fossil fuel; the high capital costs of a full solar thermal power-plant for electricity generation can be diluted since part of the equipment already exists in the fossil fuel power-plant.

The configuration here studied is the solar-assisted reheating of the combined-cycle plant in Carregado, in central Portugal. Solar integrations via retrofitting and during the project phase of a new plant are studied. Thermal efficiencies for both scenarios and for different levels of solar contribution are calculated using the steam tables. It is concluded that the integration during the project phase guarantees the best use of the investments in equipment.