The Application of the Thermal Stabilization Prompted by the Ice Cover Expansion Considering the Energy Production Optimization in the Dam-Reservoir Coupled Systems on the Vistula River

In this study, the thermal stabilization of a water resource together with an energy production optimization in the power plant of the dam–reservoir coupled system is conducted. This coupled dam system is designed to consist of a primary (Włocławek) and secondary (Siarzewo) dam due to the erosion control aspect. The other beneficial aspect of this coupled dam design is to have an additional power plant, with the aim of achieving more efficient renewable energy production. One of the factors to be included in the conditions influencing the energy production is the ice formation in the reservoir and tailwater due to the hydrodynamic and meteorological conditions of the site location. Frazil formation and jam may reduce the power plant efficiency. The concept of thermal stabilization, based on the previous studies, refers to providing the ice cover in the reservoir section of a dam to isolate the water from thermal condition. In this research, the ice cover expansion is triggered by the discharge reduction over a specific time and the entire study site. The optimized discharge for stimulating the ice cover through the night was found based on the results, leading to the desired thermal stabilization. This power loss emerged by reduced water withdrawal in the specific time during the day (nighttime), and will be remedied by the more suitable hydrodynamic condition over winter.