Simulation of potential enhancements in parabolic trough solar field start-up controllers using nowcasting systems

The yield of solar thermal power plants is strongly affected by disturbances in the irradiation condition through passing clouds. This effect is even more prominent when the clouds shade the solar field only partially as the irradiance situation cannot be fully measured by few measurement points in the field. In this paper, the benefit of using nowcasting systems to produce highly resolved irradiance maps on the field during start-up is studied. A simulation tool is used to dynamically model all the loops and piping in a reference commercial solar field. Automatic solar field controllers allow the model to operate during different situations. The performance of the field under a reference state-of-the-art controller is compared against a controller using the irradiance maps from nowcasting systems. The benefit during start-up processes is found to be significantly lower than the benefit the system makes during normal solar field operation. However, there is more potential shown for more advanced controllers, like model-predictive control.