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.
We have investigated the potential of different individual lakes, such as Lakes Constance or Zug, as energy sources for heating and cooling purposes in previous consulting and research projects. In a next step, the potential for using lakes and rivers in Switzerland as sources and sinks of heat will be assessed in a project financed by the Swiss Federal Office for the Environment.