Abstract
In lakes and reservoirs we can gain high contrast of temperature differences between impounded waters and air as well as between surface and deep layer waters. They could be available for power generation, once we succeeded in developing efficient thermal power generation systems. As a feasibility studies for utilization of lakes thermal energy, the authors performed an analysis to describe density structure and annual thermal cycles in temperature zone lakes. In the analysis, winter stratification situations as well as freezing phase are successfully formulated, while they have never been considered in any lake models so far.
