A building in Norway has become the world's first to be renovated to produce more energy than it consumes.

The designers say the re-build could be a model for more energy-positive buildings around the world.

The Powerhouse Kjørbo building will even generate more energy when it is operational than was used for the production of its raw materials, making it one of the least environmentally harmful constructions of its kind.

“Even when you take into account their complete life cycle, including all the energy used to produce building materials, the buildings will still be energy positive. This is probably one of the world’s most energy-efficient renovation projects,” says Philipp Müller, one of the lead designers for the project.

“We also want to ensure that all new materials are recycled after use, without losing any of their qualities. This is one of the reasons we are using aluminium, including for all the window profiles.”

It is difficult to overestimate just how tough this was to do.

Designers had to calculate the total energy requirement for everything that went into the building, and offset it with on-site generated power over the life of the building.

Powerhouse Kjørbo’s energy requirements, including heating, cooling, ventilation and lighting, will total just 100,000 kWh per year.

But energy will be generated by solar panels, which are expected to produce over 200,000 kWh per year and supply excess energy to the power grid.

Heat loss is cut by tight-fitting walls, ceilings and windows, and advanced insulation.

The building has been re-opened in recent weeks, and will continue to host a number of firms dedicated to on developing energy-positive projects.

“Powerhouse Kjørbo illustrates that it is possible to construct a building that is both environmentally correct and profitable, and this makes us tremendously proud,” said Klaus-Anders Nysteen, chief executive officer of Entra Eiendom, the owners of the building.