Today, a new heating facility on the shores of Lake Geneva was inaugurated. Le News was shown around the plant by an engineer from the maker, Celsius Groupe e. The largest of its kind in Switzerland, it takes heat from the lake, and has enough capacity to heat around 400 buildings.

Finding the facility is challenging. Located between the road and the lake, at the far end of a small camping ground, in La-Tour-de-Peilz, between Vevey and Montreux, it is easy to miss, whether approaching by road or by lake. Like an iceberg, most of it is under the surface.

A descent down stairs, followed by a lift ride penetrating two floors, gets you to the heart of the action. At this level you can see where the water enters from the lake, before being pushed up a level through fat pipes, to a rack of heat exchangers. From there the resulting warm water rises a further level from where it is pushed out under the road, on its way to local homes, where building-based heat pumps work the final magic, creating hot water for heating and showering.

How it works

The system is made up of three elements. The first, continually takes water from the lake, using a heat exchanger to extract around 3 degrees of heat from it, before discharging the resulting cold water back into the lake. The second is a closed system which sends water around in a loop, through pipes, to the buildings. The final part is the heat pumps, which are installed in all of the connected buildings. These heat pumps extract and compress heat from the (warm) water before returning it, cold, to the lakeside facility, ready to be heated again via the heat exchangers.

The water, taken from 70 metres below the surface, is constantly around 6 degrees. The heat exchangers take 3 degrees from it and send it back. The pumps, filters and heat exchangers are electric. The system effectively magnifies energy. Every watt of electricity used produces 3 to 4 watts of heat energy.

A heat pump employs a substance that shifts from being a liquid to a gas and back again depending on the temperature. This refrigerant flows through it and is assisted in its transformation by a compressor, which makes it hotter when it’s in a gaseous state, and a condenser, which helps it return to its liquid state once the hot gas has dispensed its heat. On the input side, flows the warm water from the central facility. On the other side is a boiler which captures the concentrated heat used to heat the house. Electricity runs the machine, which essentially concentrates the heat out of the warm water, bringing it to a higher more useful temperature.

What it cost

The total cost of building the facility came in at a cool CHF 30 million. With 400 homes connected this comes out at CHF 75,000 a piece. Add to this the CHF 15,000 cost of converting a home, and the all in cost is CHF 90,000. Is this a lot of money? Funded at today’s low interest rates the cost is minimal. And, if the choice comes down bequeathing to the next generation a home with a bigger mortgage, instead of an overheated planet, the cost becomes easier to justify.

Add the costs of maintenance and electricity to the interest, and the ongoing cashflow climbs a bit. However, given the 1 to 3 (possibly 4) energy output uplift, it still looks like a pretty good deal. In addition, given much of the money is already spent, these costs are set, making the future outgoings more stable, than for example, the fluctuating cost of fossil fuels such as gas and heating oil.

In addition, the lake’s fish get sent a bit of cool water, probably welcomed, during increasingly frequent heatwaves.

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