It stays clear here, even during a blackout

If the storage reservoirs are empty at the end of winter, there is a risk of a power shortage in Switzerland. In the worst case, the network is interrupted hourly. Then Mr. and Mrs. Schweizer are sitting in the dark!

All? No not all. Ernst Oschwald (63) and his family in Walterswil SO have their refrigerator and washing machine running even when the power is off. The turning off of the lights is also not announced. And the heat pump continues to supply heat.

A solar system has been installed on the roof of their more than 200-year-old house. The solar surface of 110 square meters reliably supplies energy. In the basement is a battery tower with a storage capacity of 20 kilowatt hours. In the event of a power failure, the system switches to emergency power.

Battery bridges power failure

“If the power grid goes down, we don’t even notice, at least not right away,” Oschwald says. “Only at night, when the street lights go out and the neighbors stay dark.” The stamina of his power island depends on the season and the weather. “In the summer we are 100 percent self-sufficient,” says the Solothurn.

Even in winter it supplies electricity. In order for him to lose power, too, the system would have to be covered in snow or the sky would have to be cloudy for days. “Thanks to the battery, we can always bridge a power cut of four or eight hours – even when the heat pump is running.”

Many systems fail during a blackout

Fortunately, who has a photovoltaic system? Unsure. “Many people think that a solar system protects them from a blackout,” said David Stickelberger (60) of the Swissolar association. “Most solar systems depend on grid delivery or they won’t work at all.”

In order for a system to function on its own, a hybrid inverter is needed, which makes the home network depend on the general power grid. And it needs a powerful battery. “The so-called isolated operation is also possible without a connection to the grid.” With certain systems, single-phase emergency power operation is even possible without a battery system, which Stickelberger says is sufficient for at least a few lamps.

There are no figures on how many systems have such an isolated solution. Stickelberger estimates that no more than a third of solar system owners have the system. “However, the demand for batteries is increasing significantly,” says the expert. The solar energy market is also booming. If you only want to make provisions for a winter power shortage now, you are too late. The waiting time for solar panels is currently one year.

“Pure luck”

Oschwald emphasizes that it was pure luck that he switched to photovoltaic energy just before the impending power shortage. Because he had to replace his gas heater, he switched to sustainable energy.

The project was managed by the self-build cooperative SolAar. Oschwald installed the system together with his sons in the summer and put it into operation in July. And if he produces more electricity than he consumes, his electricity supplier pays him a fee.

Oschwald does not expect a power outage

Does Oschwald invite the neighbors to the warm room in the event of a power failure? “If anyone wants to come over because they’re at home in the dark and freezing cold, we’re open,” he says with a smile. He doesn’t think there can be jealous people. “But I’m sure a few people in the village want to know why my light is on.”