For most of us, life in the city of Trondheim, Norway, would take some getting used to. At 63 degrees north of the equator, it receives but five hours of daylight in the winter and a full 20 hours of daylight in the summer. Trondheim’s extreme seasonal shifts would seem anything but optimal for generating consistent solar power, but the global architecture firm Snøhetta just completed a building in the city that proves otherwise. The structure generates twice as much energy as it needs through the sun—enough to offset the hidden energy costs that are part of the building’s construction and eventual demolition. Its solar array is so productive, it works as a mini reactor for the city, providing excess energy to neighboring buildings and electric transit.
This is the Powerhouse Brattørkaia, an office building with 200,000 square feet of space, featuring a massive skylight built into its sharply sloped, polygonal roof, allowing sunlight to filter in through the central atrium. The roof is angled to optimize for maximum energy harvesting and topped with over 32,000 square feet of black solar panels that suck as much power as they can during the long summer days and store it for the dark winter, and then some.
The entire building is wrapped in black aluminum, completing the black-on-black ensemble. It gives the office building a stark, international look that yells “corporate office” but barely hints at sustainable building. “This color might not intuitively convey ‘green’ so to speak, even though it is,” says senior architect Andreas Nygaard. “What people might instinctively associate with ‘green’—large glass facades, for example, might not always be correct . . . It is a complex equation and not always apparent unless this is your field of expertise. We hope to contribute to an increasing awareness of what solutions are actually sustainable when one considers the whole value chain, so that we can move beyond ‘greenwashing.'”
The name of the project—”Powerhouse”—describes the radical idea behind its design: that buildings themselves can help generate enough power for the city around them, ultimately paying back the energy used to build and eventually raze them when their useful life is over. In fact, this is the fifth Powerhouse that Snøhetta has built, including the Drøbak Montessori Secondary School, the Harvard HouseZero and Powerhouse Kjørbo (both of which were actually renovations), and the ZEB Pilot House (a residential project). All of these buildings have drastically different designs, and yet all of them will be a net positive to the environment over the course of 60 years.
“The size can be big or small, and the location can be urban or rural,” says Nygaard. “The key is to make the operation of the buildings as efficient as possible, and maximize clean energy production, while taking into account the whole value chain that goes into constructing, preserving, and demolishing a building.”
Could other Powerhouse buildings be constructed closer to the equator? Or is there something special about the north, where most are built, that makes the firm’s Powerhouses so efficient? Nygaard says no—the same idea could be applied nearly anywhere on Earth.
“The solar panels produce the most energy when the angle towards the sun is 90 degrees. Thus, in order to harvest enough energy for the building to be net energy positive over its lifespan, the angle of the roof needs to be adapted to this given its specific location. Closer to the equator, the ideal roof angle would be flatter and towards the poles it would be steeper,” she explains. “The area underneath the roof also plays a central role here—the more square meters in the building, the larger the surface needed to harvest solar energy to ensure that the building produces a net energy surplus. (Thus, if you install solar panels on a skyscraper for example, this would hardly produce enough solar energy to supply the whole building with energy, unless one uses the façade as well). So the concept could be used anywhere in the world that has a decent amount of sun exposure, and then it needs to be adapted to the specific location, size, etc.”
In other words, we can create cities that don’t destroy our environment, but we need to do it more intentionally than we do now. We can’t build them too tall, and we need to angle them toward the sun. That makes me picture fields of sunflowers, each stretching for a sip of energy. Sounds beautiful.