Lake Zurich is a popular recreational area for people living in and around the city. However, it also serves as a sustainable source of energy. ewz, a developer of intelligent, sustainable energy solutions, has been supplying more than 70 properties around Lake Zurich with “green energy” from the lake for heating and cooling.

The lake water is collected at a depth of 10 to 15 metres and sent through pipes over several hundred metres to a number of pumping stations and power plants. There, heat exchangers extract a few degrees of its natural heat and transfer it to the district heating network. Heat pumps use this heat to bring the water in the buildings up to the required temperature  so that it can be used for heating and hot water supplies. As a result, the buildings connected to the scheme benefit from sustainable warmth in winter. In the summer, they obtain energy for their cooling systems either directly from the lake water or via cooling plants. At the end of the cycle, the lake water is returned to the lake in a chemically unchanged form around 150 metres from the shore.


Swiss Life Asset Managers has several properties in the Lake Zurich area. Four of these are connected to the Falkenstrasse lake-water network and seven to the Escherwiese network. How did this system come about?

In the course of ongoing maintenance works and the resulting replacement investments for heating installations, we were constantly evaluating various alternative options. We then became aware of the ewz's lake-water networks. Sustainability and climate protection, economic aspects, reliability and round-the-clock service were particularly important to us.

The connection to the various lake-water networks accurately meets these requirements: it provides us with a plentiful supply of CO2-free energy and uses Lake Zurich, which is right on our doorstep, as an environmentally-friendly source of energy. A smooth-running process as this one is of importance to us. 

First published by “4 Solutions von EWZ”, May 2021

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