The Swiss village of Urdorf is home to new residential buildings, called Umwelt-Häuser von (environmental houses of) of Urdorf. The residents live energy self-sufficiently but they do not have to compromise on comfort. Solar panels are installed everywhere in the building, and there is a power plant in the basement. Power-to-X is a key technology for living without fossil energy.
(Translation based on an article by Daniel Schneebeli if Tages-Anzeiger)
The three apartment blocks stand in an inconspicuous neighbourhood in Urdorf – wedged between the hospital and the Limmattal Cantonal School. They blend seamlessly into their surroundings.
But if you take a closer look, you will notice that these five-storey buildings are anything but ordinary. Between each of the visitor parking spaces, a row of drivable solar panels is embedded in the ground. The green façade also consists of solar panels, and wind turbines rotate on the flat roofs. “These are our lift power stations. They supply as much electricity as the lifts need,” says Andreas Kriesi. He is deputy managing director of the Umwelt Arena Foundation, which built the houses with its partners during the Corona period and now rents them out.
On the top floor, lives Dominik Wlodarczak with his wife in a three-room flat. Until recently, the two were at home in an old building that was over 100 years old, and they were in the mood for a new living experience. “We live in an environmentally conscious way, but we weren’t looking for a climate-neutral settlement,” says Wlodarczak, who works as a developer in a building materials company.
Wlodarczaks came across the Urdorf project through the usual marketing channels. They were taken with the idea of keeping their own energy consumption under better control: “We wanted to find out how much energy we could save without sacrificing comfort.”
In the meantime, the Wlodarczak couple has been living in Urdorf for nine months. Their flat is flooded with light, there is a large cooking island in the living room, and a terrace of 20 square metres on each side.
At the dining table, the Wlodarczaks take stock: “We haven’t even used half as much energy as is usual in a comparable three-room flat,” says Dominik Wlodarczak, switching on a tablet. In terms of hot water consumption, they have not even come close to the budget the landlord allows them in any month. For electricity, the green columns showing consumption are also below the red budget line in eight out of nine months.
Only in July is the end of the column slightly above. “In the heatwave summer, we needed a lot of energy for cooling here on the top floor.”
The Umwelt Arena Schweiz foundation in Spreitenbach has already realised several pioneering projects for environmentally friendly construction in the canton of Zurich. One of these is a completely energy-autonomous apartment building in Brütten, which does not need any external energy supply. The energy demand is covered by solar roofs and facades. The surplus electricity from the summer is not fed into the grid, however, but converted into hydrogen and stored in large tanks in the garden. However, this system is too expensive for profitable operation.
Things are different in Urdorf, as Andreas Kriesi says. The three apartment buildings are connected to the electricity and gas grids. Thanks to intelligent energy management, however, they can be 85 per cent self-sufficient even in the winter gap, when the solar panels supply little electricity. On the one hand, this is made possible by a battery in the heating centre, in which surplus electricity is stored for a short time each day for consumption in the evening. But the most important part is the hybrid box, which is responsible for intelligent energy management. It ensures that the electricity generated in the house is consumed in the house first.
In the second priority, it flows into the battery. In third priority, the hybrid box feeds the surplus solar power into the grid. At Limeco in Dietikon, it is converted into synthetic methane gas and temporarily stored in the gas grid. In winter, when solar power is scarce, the hybrid box also becomes a small power plant. The box draws the stored gas from the grid and converts it into electricity and heat. The heating system is also supported by five geothermal probes.
The construction costs in Urdorf are about five per cent higher than usual because of the solar panels and energy management system. “This is bearable and even advantageous for investors,” says Kriesi. The value of the property is higher, and what is most interesting, according to Kriesi, is that the returns are also above average. The 39 flats are rented out somewhat more expensively than is usual in Urdorf. A two-and-a-half-room flat is available from 1500 francs, a four-and-a-half-room flat from 2500 francs.
Is the Umwelt-Arena practising rent profiteering? “On the contrary,” says Kriesi, “our tenants actually benefit.” According to Kriesi, they save up to 250 francs per month on electricity and heating costs, because electricity and heat are free – if you stay within the given energy budget. The budget is tight. For a four-room flat, there is only 2000 kWh per year – half the usual average.
But according to Kriesi, this goal is realistic. All flats are equipped with the most economical appliances and LED lights. Thanks to high-quality insulation and glazing, hardly any heat is lost. And even when showering, 30 per cent thermal energy is saved. The used hot water is used to preheat the cold water flowing into the drain.
Self-monitoring is also helpful for the economical use of energy, says Kriesi. The energy budgets provide an incentive for tenants to save. Dominik Wlodarczak confirms this: “You automatically pay attention to your own consumption. However, it is more the ambition to stay under budget than the threat of energy costs that encourages saving. For example, the Wlodarczaks never use the tumble dryer, even though there is one in every flat. They also always turn off the Wi-Fi when they leave the flat. “That makes a surprisingly big difference,” Wlodarczak notes.
Within just two months, the Umwelt Arena had rented out all the flats, and not to “eco-fundies”, as Kriesi emphasises. There are no climate policy requirements for the tenants. Environmentally friendly behaviour is welcomed, but it is not an award criterion. People are allowed to fly on holiday and drive a car. There are 52 spaces in the underground car park. 46 are rented out and by no means only to e-mobile owners. “We don’t want to educate people,” says Kriesi.
Wlodarczaks don’t have a car. “We are well served by public transport here,” says Dominik Wlodarczak. The only thing he has is an electrically powered Vespa – for local transport. It is charged from the private electricity budget with an extension cable, which he always lets down from the balcony to the motorbike car park: “I can’t very well plug in in the underground car park and charge my vehicle at general expense.” Despite this inconvenient charging process, Wlodarczaks would move back to Urdorf. Wlodarczak even says, “If we ever move, it would have to be a living arrangement like this again.”
In the end, however, he does have one restriction and one wish. The restriction: “Those who like it a little warmer in the living room in winter might be disappointed.” Because you can’t heat it to over 21 degrees here. The wish: “It would be nice if you could check the power consumption of each appliance separately on the tablet.”