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Zero Sun™ – our project of the future has a dark side

Building a modern house that is self-sufficient in solar energy is one thing. But it is quite another to do it where the sun is conspicuous by its absence for much of the year.

På svenska. Zero Sun is the experiment that demonstrates that solar power – when combined with the right technology – is one of the keys to the future supply of sustainable energy. The winters here in the Nordics are long, cold and dark. Our aim is to show that if the experiment can be done here, it can be done anywhere.

Self-sufficiency in solar energy. Even in darkness.

What we have built near Vitberget in Skellefteå is no ordinary house. Even though it may look like it from the outside. Because this comfortable house with modern furnishings has a unique energy system on the roof, inside the building, and underground.

It is an energy system where solar cells, batteries, electrolysis, geothermal, hydrogen and fuel cell operation interact to ensure that the house is able to cope using its own energy supplies in the tough Nordic climate with long dark winters and short bright summers.

This holistic solution means that the house can store solar energy during the sunny months, and then use the surplus in darker times. Something that used to be virtually impossible.

A real-time experiment with technology from around the world

With Zero Sun, we and our partners aim to explore the possibilities of solar energy and make the technology behind it even more efficient, reliable and accessible. We can take what we learn here and use it to help people, companies and organizations – even far beyond our own sun-starved Nordic latitudes.

Zero Sun is not intended to be a finished solution, but an experiment where we will test, evaluate, improve and go again.

– Zero Sun is part of Skellefteå Kraft’s efforts to learn more about the next generation of energy systems. To drive the transition to a 100% renewable energy system, we need to be inventive and focus on technical innovation, says Fredrik Jonsson, Head of Business Innovation at Skellefteå Kraft.

The house is fitted with solar panels on the roof. The electricity generated while the sun is shining is firstly used for the direct energy supply of the house, domestic electricity and hot water. The excess is then stored in batteries.

When the batteries are full, an electrolyser starts producing hydrogen gas. The hydrogen gas is piped to a separate building on the site, where it is stored.

The hydrogen cylinders store the excess sunlight for the times when energy is needed most. For example when it is dark and cold.

In winter the process is reversed. The hydrogen gas is piped back to the house into a fuel cell, where the gas is converted into electricity to recharge the batteries.

The fuel cell is also water-cooled so the waste cooling water can be reused for heating and hot water.

You can read more about the experiment at

Fredrik Jonsson

”We are constantly looking for opportunities to be part of the solution. That’s why we liked the idea of building a self-sufficient solar energy house in one of the darkest places on earth”

Fredrik Jonsson, business area manager innovation at Skellefteå Kraft

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