Optimal Operation Of A Concentrated Solar Thermal Cogeneration Plant

The integration of a new central receiver concept for concentrated solar thermal (CSP) into a cogeneration plant for electricity generation and seawater desalination is proposed. To optimize the conceptual design proposed, physics-based system-level dynamic models are developed including the energy storage system, a regenerative Rankine cycle and the multi-effect distillation (MED) for seawater desalination. The model predictions are validated over a wide range of operating conditions. Operation of the plant is systematically optimized through formulation as a nonlinear program via the sequential method. Both time-variable and time-invariable operating conditions are considered. A heuristic global optimization approach is used. Two case studies are considered, one with a time-invariant feed-in tariff (TIFIT) and another with a time-variable feed-in tariff (TVFIT) with the same time-weighted average using Cyprus as a case study. For the TIFIT, cogeneration of power and water via utilization of solar energy does not yield maximum income. In contrast, the implementation of a TVFIT results in a higher income and more closely follows the electricity demand, thereby reducing strain from the electricity grid via production of renewable electricity when it is most needed, i.e., on-peak hours.