The Powerhouse movement seeks to inspire net-positive buildings
What if instead of just reducing the environmental impact of the buildings we construct or striving "just" for zero energy status, we could construct or design structures that have a net positive effect on the planet? That's the mission behind Powerhouse, a green building framework that has its roots in Norway.
Powerhouse is a collaboration between various companies involved in numerous aspects of building design and construction. The partnership consists of Entra Eindom, a real estate company; Skanska, involved in construction and development; architectural firm Snøhetta; environmental organization ZERO; aluminum extrusion company Sapa; and consulting firm Asplan Viak.
The organization’s collective purpose is demonstrating that making buildings energy-positive is possible, even in a cold place such as Norway. Here's the main definition (PDF) of the structures that it hopes to inspire: "A Powerhouse shall, during its lifetime, produce more renewable energy than it uses for materials, production, operation, renovation and demolition."
The framework that the group has developed also includes additional criteria, including the notion that the building must be commercially viable and that it also demonstrate qualities such as good architecture and indoor climate. In other words, that people will want to live or work within them.
What qualifies as a Powerhouse?
A Powerhouse needs to provide value to the environment, its occupants, its owners and the companies that work on its construction. In this way, the building is sustainable both environmentally and financially.
Klaus-Anders Nysteen, CEO at Powerhouse partner Entra Eindom, commented on this aspect of a completed Powerhouse project, Powerhouse Kjørbo, in an article on the website of another Powerhouse partner, Skanska.
"Through Powerhouse Kjørbo we are showing that it's possible to construct a building that provides a positive result, not just environmentally, but financially as well," Nysteen said. "Making a commercial gain is a basic precondition for investing in this type of project in the future."
To achieve the net positive goal set out by Powerhouse, builders must focus on the entire lifecycle of the building and the materials used to construct it, said Rune Stene, managing director of Powerhouse.
Producing aerated concrete, for example, generates 442 grams of carbon dioxide emissions (PDF) for each kilogram of concrete. Manufacturing aluminum sheet creates 2,980 grams of carbon dioxide emissions per kilogram and producing a kilogram of timber creates between 40 and 200 grams.
To counter the impact of these processes, construction companies aiming to build a Powerhouse must switch to more eco-friendly materials. That might include using more recycled materials.
"We welcome reuse of materials as we value that as zero-emission materials," Stene said. "If we can design and plan for a high degree of reuse of materials, we may reduce estimated energy for demolition, and better our energy account, reduce demand for energy production and finally reduce costs."
As another criterion for Powerhouse certification, a building must also meet the Passive House Norwegian Standard 3701. A passive house is one that takes advantage of passive energy such as sunlight for light heating needs and uses continuous insulation to minimize heat loss. This design reduces energy demand. An energy-positive building goes beyond passivity, however, and includes energy generation through renewable sources such as solar, wind and geothermal systems.
The first completed Powerhouse project, two renovated office buildings outside of Oslo, uses rooftop solar panels that produce more than 200,000 kilowatt-hours of energy each year.
Thanks to the energy-efficient design of the buildings, this is more than twice what the building consumes. The renovation helped reduce power consumption by at least 90 percent. The site uses ground wells to provide heating for radiators, water and ventilation systems; as well as cooling during summer months. The original structures themselves were more than 30 years old.
Developers may be able to combine Powerhouse ideas with other green building certification standards, including those commonly in use in their home country. (Although the Powerhouse collaboration began in Norway, the organization sees opportunities for projects in the rest of the European Union, the United States and other parts of the world.)
For example, the first two Powerhouse projects are certified as "outstanding" under the Building Research Establishment Environmental Assessment Method (BREEAM), which evaluates construction projects in a range of categories including energy, land use, water use, materials, health and well-being and transportation.
The rating of "outstanding" under BREEAM is equivalent to the platinum rating under the Leadership in Energy and Environmental Design (LEED) certification scheme used in the United States. Use of LEED is widespread in the United States, especially in cities such as Philadelphia, where the rate of green adoption is nearly 38 percent.
Several other green building standards emphasize energy-positive operation, such as the Living Building Challenge. Buildings that achieve this certification must be self-sufficient, produce more energy than they consume and treat all water on site. Buildings that already meet other green standards such as LEED and BREEAM likely will have an easier time achieving Powerhouse status.