Nearly 60 % of the world’s carbon dioxide emissions are attributable to the energy sector. Cities are one of the biggest sources of emissions and, just 100 cities are responsible for 18 % of those emissions. One solution to the problem could be the creation of more energy-positive city districts, i.e. specific areas, or neighbourhoods in a city that generate more energy than they consume, thereby helping make energy systems more green.
Stockholm’s first energy-positive building is located in the district of Norra Djurgårdsstaden. Over the course of a year, the building generates more energy than it consumes. It is equipped with solar cells that generate energy, highly effective insulation and storage for excess heat in boreholes.
– “Norra Djurgårdsstaden is a great example of an energy-positive city district, or anyway, one that is nearly that,” says Kerstin Rubenson, Project Manager at RISE. By definition, an energy-positive neighbourhood must consist of several buildings that actively manage their energy consumption and exchange energy between themselves. We’re currently working with similar trials in both Malmö and Lund. Thus far though, we don’t have a city district in Sweden that has been fully tested,” she says.
Supplement to large-scale solutions
In a country like Sweden, with large-scale energy facilities and advanced systems for district heating, investing in small-scale, local solutions might seem unnecessary. But Kerstin Rubenson disagrees:
– “There are several reasons for wanting to create energy-positive city district. The environmental and resource-efficiency aspects are important. We want to make the best use of the resources and opportunities that we have available to us. We want to give the entire energy system a push in the right direction and make renewable energy a larger component of the system. But large-scale solutions aren’t enough. We also need small-scale ones,” she says.
Legislation stands in the way
Challenges with different sources of energy
When talking about energy-positive neighbourhoods, the sources of energy referred to are primarily electricity and heat. How the two are managed, locally, also varies.
– “Thermal energy is quite simple to manage and there has been much progress in the ability to make use of residual heat in Sweden and distribute it among buildings via the district heating network. Doing the same, on a large scale, with electricity production is more difficult to achieve and thus far, we haven’t been able to overcome the challenges associated with seasonal electricity storage. Legislation stands in the way as well and there are many rules and regulations when it comes to transferring electricity from one property to another,” says Kerstin Rubenson
So, how do we make energy-positive neighbourhoods a reality?
– “We must start by convincing residents in the area to lower their energy consumption. We’ve been able to see that household energy consumption peaks in both the morning and in the evening, when people return home from work. And, although we can’t fully control those behaviours, we can still influence them by, for example, variable pricing models that encourage major customers to adapt their energy consumption to other times of day. Policy changes regarding the transfer of electrical energy are also needed, along with a revision of how varies types of energy are taxed,” concludes Kerstin Rubenson.