Eco-neighbourhood with Solarus PowerCollector in Thierrens, Switzerland
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First eco-neighbourhood realized in Switzerland

First eco-neighbourhood realized in Switzerland

THIERRENS – May 2017 – In connection with the new law and the vote of May 21, Marc Ponzio presents the first eco-neighbourhood in Switzerland , which means it will be fully self-sufficient in energy. Clean and renewable, of course.

In Thierrens, on the heights of the Gros-de-Vaud, the construction of three buildings, fifteen apartments and two offices is being completed. While, at first glance, nothing distinguishes this small neighbourhood from the many others located in the country’s villages, it will be the first one in Switzerland to be fully self-sufficient in energy. In other words, the various solar and wind energy facilities it is provided with, together with reinforced insulation and new energy storage methods, will provide its inhabitants with heating, hot water and electricity, including charging their cars in the underground garage.

A better world

At the start of this undertaking, Marc Ponzio, its founder, was looking for new offices for his sanitary design company. Since its creation by his father in 1970, the company has worked on very large projects such as the Lausanne University Hospital (CHUV) or part of the University of Lausanne (UNIL), and has accumulated knowledge in the field of heat and rain water recovery. Having chosen a new construction, the entrepreneur was naturally concerned about its environmental impact. “I’m nearly 60 so I suggested to a few friends that we should create a company to make a better world, while enjoying ourselves at the end of our careers!”


Anny Frosio, who is now the company’s head of engineering, echoes these thoughts: “Switzerland signs climate treaties and at some point we need to get down to it and come up with new solutions”. As an HVAC engineer, she has, in her twenty years of experience, contributed to the spectacular development of various renewable energies, from wood heaters to the most advanced solar panels such as those installed in Thierrens.

Developed within the University of Gävle in Sweden, they are owned by the Solarus company, which manufactures them at its own plant in the Netherlands. This is important as, from a philosophical standpoint, this young company did not want panels manufactured at the other end of the world, which while perhaps more cheaply, would then lose many of their ecological and ethical virtues. Instead, the company plans to manufacture them as close as possible to the point they are in demand.

The panels on the roofs of the eco-Thierrens buildings are hybrid, as they can produce both electricity and hot water. They are made of plastic, a bit like motor vehicle headlights. Inside each box, weighing just 50 kilos, photovoltaic sensors and a gutter-shaped mirror reflect the Sun’s rays onto the pipes in which water is flowing. “While they are not the only existing models, they are a real revolution”.

Valuable energy

In terms of numbers, these 320 m2 of hybrid solar roof, plus 320 m2 of conventional photovoltaic roof, 80 m2 of high-temperature thermal roof, together with 200 m2 of access road, which is also photovoltaic, will produce some 150,000 kWh of electricity per year, 50,000 kWh of which are needed for the consumption of the fifteen apartments, 10,000 kWh for the two offices and 55,000 kWh for mobility, i.e. the charging of electric cars.

In this Haut-Jorat region, where the wind blows strongly, four or five small vertical wind generators will complete the system. And as all energy is valuable, it will also recover wastewater. “Shower water has an average temperature of 35°C so 15 to 20°C can still be recovered before it flows away into the sewer. All energy is noble.”

The energy self-sufficiency of the eco-neighbourhood is also provided by a huge 85,000 liter tank within which coils and a double boiler principle allow the storing of the hot water needed for households, and even during the summer, the redistribution of cold air in the double-flow ventilation system (which also recovers the energy contained in the stale air). Note that rain water is also recovered and used to supply toilets and laundry washing machines. “Rain water has no energy value but it is all about sustainability. We tried to do everything.”

The Ponzio Group was thus invited to present its project, under the “Good ideas in Switzerland” banner, during the 2015 United Nations Climate Change Conference, COP 21, held in Paris. “People around the world showed their interest in this, whether for fitting out a tourist resort in Guadeloupe, or for clinics in Africa. The temperature in the tank can reach 100°C, and could be used to disinfect medical instruments. This steam could also be used to generate electricity here in the summer.”

For Marc Ponzio, the Thierrens eco-neighbourhood really runs like a laboratory. “Once the apartments are occupied and the offices are completed (the first residents will move in within a month from now and a few apartments are still available), the buildings will allow a more accurate analysis of consumption cycles. We will be our own guinea pigs.”

At the core of the system, there are still batteries which, since their cost has decreased, can now be installed in homes to solve the problem of storing electrical energy. Any “excess” energy generated during the day will thus be used at night to charge cars. The electric car manufacturer Tesla is also very interested in producing such batteries. “Which brings us back to California, where the hippies of the 1970s, who used to build greenhouses and recover rain water, experimented with many of these principles. We have brought them together and perfected them.” The tank is thus expected to provide three weeks of hot water without sun and the 400 kWh battery will allow four days of operation (without charging cars).

To the question posed in a vote on May 21 about the 2050 energy strategy, the designers of the Thierrens eco-neighbourhood provide their practical experience: in 2017, it is already possible to construct a building which is both self-sufficient and run entirely through renewable energy. Just the opposite of the cold shower announced by the opponents of the new law on energy. Marc Ponzio also notes that in less than two years, his group has already created more than fifteen jobs – engineers in electronics and hydraulics, electrical and heating engineers – and has trained new specialists. “We are already in 2050!”

Marc Ponzio estimates the additional cost of its eco-neighbourhood to be 20% compared to similar buildings in the same area, primarily due to the particular care given to their insulation. At the price of energy (electricity, oil or gas), this difference will be quickly written off. The same applies if the system is tailored to older buildings. “Leaving fifteen or twenty years of clean energy to one’s children is really valuable. An inheritance is now not just about money, but also energy.”

Published in L’illustré (Swiss Magazine)

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