I often hear about nZEB buildings (nearly Zero Energy Buildings) and less often about NZEB (net-zero energy buildings). What is the difference between the two acronyms? How many people know what they really mean? Which projects aim to meet these requirements? And what is net-positive architecture?
The next challenge for our studio (www.lcarchitetti.com) is no longer to build passive buildings close to zero energy use (nZEB), but to design buildings that meet the requirements of net-positive architecture. In practice, the goal is to design buildings that generate more energy than they consume – paradoxically, even by renovating nearly passive or passive buildings. I say this provocatively because the property market is still lagging far behind the latest trends in eco-friendly and sustainable architecture, and there are still very few good examples in Italy.
In Europe, however – in Norway, to be precise – a building is set to rise in the town of Porsgrunn that will further define the new horizons of green architecture: Powerhouse Telemark, designed by the architects of Snøhetta (https://snohetta.com/projects/283-powerhouse-telemark). It is not the first experiment of its kind in the world, but it is certainly the northernmost, in a very harsh climate with very little direct sunlight. The challenge is ambitious both technically and economically, and its completion could become a milestone of this new trend. Powerhouse Telemark has a distinctive diamond shape that makes the most of natural daylight for interior lighting while allowing the photovoltaic modules to capture as much solar radiation as possible. Its high level of sustainability is also ensured by materials from renewable sources and recycled materials. The energy it generates will fully meet the needs of the building, which will have a floor area of about 6,500 m²; completed in 2019, it will be 11 storeys tall and house offices and shared spaces open to the public. Finally, Powerhouse Telemark also aims to prove the economic sustainability of such projects: its construction cost of 17 million dollars will be fully covered by the profit from surplus energy over the building’s whole life (estimated at 60 years).
Improving on and going beyond nZEB buildings
The concept of zero-impact buildings, energy self-sufficient, is now well established and increasingly put into practice. Net-positive architecture aims to create green, highly efficient buildings perfectly integrated into their urban or natural setting, so as to have a truly “positive impact”. They are designed not only to keep energy use to a minimum but to produce more energy than they use over their entire life cycle, giving the surplus back to the community. Net-positive architecture is set to play a key role in the coming decades, as the energy-saving challenge becomes ever more pressing. Today there are a few hundred certified positive-impact public buildings and private homes worldwide, and each is a laboratory for energy solutions that can later be applied on a large scale.
