Not content with simply aiming for zero emissions, European policymakers are embracing a growing trend to create entire neighborhoods that are net exporters of energy.
There are 10 to 20 such pilots underway today across the continent, depending on the precise definition of a "positive energy district." But there are plans to have at least 100 such districts in Europe by 2025, combining efficiency measures with distributed generation to deliver a net surplus of energy over the course of the year.
Work on positive energy neighborhoods has been underway for the last five years, evolving as an extension of zero-energy building concepts, said Christoph Gollner, program manager for positive energy districts and neighborhoods for sustainable urban development at the Austrian Research Promotion Agency.
In 2018, the European Commission published an implementation plan for positive energy districts, saying they can raise the quality of life in cities, contribute to reaching the EU's climate targets and boost Europe's know-how in clean-energy technologies.
Gollner said other countries, including the U.S. and China, are watching Europe's progress on positive energy districts. Within Europe, the question is whether the concept will scale quickly enough to help the trading block achieve its carbon reduction targets.
“I think it’s very ambitious,” Gollner told GTM. “The main challenge is retrofitting. Most positive energy districts are focusing on new developments. But I’ve worked in retrofitting for many years, and these processes take a long time.”
It's not easy extending energy efficiency and distributed generation from buildings to entire neighborhoods. The first challenge is governance: City administrations are traditionally organized in silos, which makes it hard to develop the collaborative planning processes and policies required for positive energy districts.
And there are many thorny legal issues, since regulations around topics such as peer-to-peer energy trading are still in their infancy.
“This concept depends a lot on the nontechnical side more than the technical side,” said Miguel Ángel García Fuentes, energy area manager at Cartif, a Spanish technology center, during a presentation at the Smart City Expo World Congress in Barcelona, Spain last year.
“We have the technologies. From the nontechnology side, there are elements that have to be solved in order to ensure that this concept works. Regulation is one of the elements.”
Spain, for example, had strict regulatory barriers regarding solar self-consumption until recently. That meant that a positive energy district pilot called Remourban, in Valladolid, was forced to use solar PV for district heating rather than electricity generation, he said.
In Limerick, Ireland, where a positive energy district program is wrestling with an old building stock, “it is really about behavioral change,” said Mihai Bilauca, head of digital strategy and EU programs at the city and county council.
While the Limerick positive energy district program, called +CityxChange, is succeeding in introducing some energy-efficiency measures for buildings and has plans to extract hydropower from a river that runs through the city, one of the project’s most important components is a citizen observatory.
This allows residents within the positive energy district to have a say in the program, which is shared with Trondheim in Norway, and which aims to integrate more than 4,500 gigawatt-hours of new renewable generation into the electricity and heating systems of both cities.
Another challenge is simply defining a positive energy district properly. Should, for example, "surplus production" take into account fuel used in transport systems or embodied energy in buildings?
Neighborhoods don't necessarily need to be completely energy-autonomous, Gollner said. And "it doesn’t make sense to locally produce a surplus if you have, 5 kilometers away, a wind park that can be used for energy production," he said.