Powerhouse Telemark in Porsgrunn is one of a series of energy-positive office buildings designed by Snøhetta that sets new standards for low energy consumption and surplus energy production.

The 11-storey building, located southeast of Oslo, Norway, uses 70% less energy than similar newly constructed offices. It is expected to produce more energy than it will consume over its lifespan.

Key to its energy production are photovoltaic (PV) panels on the roof and south facade. These are part of an overall energy equation that also considers passive design strategies, the impact of maintenance, and embodied energy.

Generating clean energy, Powerhouse Telemark nods to the Porsgrunn area’s history of generating hydropower since the 19th century.
© Ivar Kvaal / Snøhetta

Powerhouse Telemark is the fourth project completed by the Powerhouse brand. The brand is a collaboration between three leading partners: Swedish project development and construction company Skanska, environmental organisation ZERO, and Snøhetta.

A staircase on the ninth floor connects the staff canteen and conference room, and guides visitors towards the rooftop terrace.
© Ivar Kvaal / Snøhetta

As described on Ecogradia by Kjetil Trædal Thorsen, Founding Partner of Snøhetta, “The idea was to be able to design and build buildings that, at least, would be fully CO₂ neutral after a lifespan of somewhere between 25 and 30 years.”

The combination of daylighting and efficient artificial lighting reduces the building’s energy consumption for indoor illumination.
© Ivar Kvaal / Snøhetta

The 8,313 sqm structure primarily houses offices, including two storeys of co-working spaces. It also contains a reception, penthouse meeting room, staff restaurant, wellness space, and roof terrace overlooking the fjord.

A skin of wooden balusters provides protection from the sun on the most exposed facades.
© Ivar Kvaal / Snøhetta

The angle of the roof plane, which maximises the amount of solar energy harvested, contributes to the striking silhouette of Powerhouse Telemark.

This, along with a 45-degree notch on the east-facing facade and timber baluster cladding, establish the building as a landmark in the surrounding Herøya Industripark.

The building’s landmark character reflects the ambition for it to be a beacon of sustainable design and the decarbonisation of new construction.
© Ivar Kvaal / Snøhetta

New energy standards for office buildings

The south facade and roof generate 256,000 kWh each year through solar energy harvesting. This is approximately twenty times the annual energy use of an average Norwegian household. The surplus energy is sold back to the grid.

The PV panels on Powerhouse Telemark generate a considerable surplus of clean energy.
© Ivar Kvaal / Snøhetta

The triple-glazed windows effectively reduce heat transfer through the glazing while allowing abundant natural light to enter.
© Ivar Kvaal / Snøhetta

The building is super insulated and has triple-glazed windows. The wooden balusters cladding the west, northwest, and northeast elevations provide shading. Low-carbon STENI facade panels and glazing complete the building’s wall surfaces.

Glass slits in the roof allow daylight penetration on the uppermost floors. With plentiful natural daylighting reaching the interior, the artificial lighting system is conservative, and energy efficient at that.

The durable staff cafeteria receives natural light from slit windows in the sloping roof.
© Ivar Kvaal / Snøhetta

The concrete slabs store thermal heat during the day and slowly emit it during the night. A low-exergy system with water loops in the border zones of each floor, ensuring efficient cooling and heating (facilitated by geothermal wells dug 350 m below ground level).

A sectional drawing shows the distinctive 24-degree tilt of the roof. The building envelope extends beyond the edges of the floor plates.
© Ivar Kvaal / Snøhetta

A low-embodied-energy interior for the long haul

Internally, the concepts of standardisation, resilience, and low embodied energy dominate the design.

Standardised and durable fittings and furniture minimise the need to refit interior spaces over time.
© Ivar Kvaal / Snøhetta

The standardisation of elements across all floors is a way to avoid the wastage that comes with new interior fitouts as tenancies change. As such, the same design, colour, and materiality is applied to all flooring, glass walls, office dividers, kitchenettes, and lighting.

Sturdy materials known for their resilience and low embodied energy give the interior an unfussy appearance and help to reduce the impact of maintenance over time. These include local wood, gypsum, and exposed environmental concrete.

Light-coloured materials and furniture complement the copious natural light in the staff cafeteria.
© Ivar Kvaal / Snøhetta

The embodied energy of materials is minimised thanks to an emphasis on reuse. The tiles on the reception desk were recycled from the local porcelain factory. Wooden parquetry flooring is made from discarded ash.

The carpet tiles are composed of 70% recycled fishing nets. Second-hand chairs have upholstery crocheted from leftover yarn supplied by a Norwegian wool factory.

An open-plan work area with moveable meeting pods can be easily reconfigured.
© Ivar Kvaal / Snøhetta

The project demonstrates effective principles for energy-positive and sustainable architecture. The BREEAM NOR Excellent certification awarded to the building legitimises its achievements.

Powerhouse Telemark follows the footsteps of its ambitious counterparts: Powerhouse Kjørbo, Powerhouse Montessori, and Powerhouse Brattørkaia. It has the capacity to redefine our expectations of future office spaces, embodying environmentally, socially, and economically sustainable architecture.

Listen to Kjetil Trædal Thorsen’s perspective on sustainable architecture in Season 4, Episode 2 of Ecogradia.