Deep lakes can be used as important sources or sinks of heat for heating and cooling purposes. This is a previously neglected renewable energy source. Recently, several new projects have been developed to use lakes in Switzerland for heating or cooling purposes. As a consequence, public awareness of this potential energy source has also increased.
In a project financed by the Swiss Federal Office for the Environment, we have investigated the potential of lakes and rivers in Switzerland to be used as energy sources for heating and cooling. The results of this study are published on the project website. We also published a review article on thee on the physical and ecological impacts of using on lakes and rivers for heating and cooling.