Climate neutral within seven years: Lessons from Sønderborg

Sønderborg, a sleepy Danish town, holds many of the keys to decarbonising Europe's towns. [Shutterstock/uslatar]

Sønderborg, a small Danish town lying just beyond the border with Germany, is a living example of a possible future for decarbonised towns – and a blueprint for study by policymakers the world over.

In April 2022, 100 European cities signed up to a pledge to be climate neutral by 2030, far ahead of the EU-wide decarbonisation targets. The Danish municipality of Sønderborg – a sleepy town with 70,000 inhabitants – is one of them.

Faith Birol, chief of the International Energy Agency (IEA), described Sønderborg as the “capital of energy efficiency,” during the global energy efficiency conference held in the town at the beginning of June.

Previous iterations of the conference were held in Paris and Dublin – so why was Sønderborg, a small town even by Danish terms, chosen to host an international conference featuring government delegations from across the globe?

For one, it is home to the Danish multinational Danfoss, a family company dealing in cooling, heating and other efficient technical solutions, which acts as the local hegemon. Moreover, however, the town’s public-private partnership “ProjectZero” provides a blueprint for climate-neutral towns for visitors to engage with and experience.

Policymakers from all over Europe make the trip. “We host a lot of different groups coming through here to see ProjectZero,” Kim Fausing, CEO of Danfoss, told EURACTIV.

And these policymakers leave with lasting impressions of happy voters, cheaper bills and a clear roadmap towards climate neutrality for their towns. 

“If you take a look at what they’ve done for neighbourhoods, you can see what’s possible,” explained Robert Habeck, Germany’s minister for economy and climate action, on 3 June. A past visitor of Sønderborg himself, the minister described the town as a “model municipality”.

“They are basically climate-neutral and have combined solar thermal energy, wastewater, sewage, heat and waste heat,” he added, while speaking to municipal policymakers.

Germany’s Habeck is but one of many policymakers touring the town’s marvels, whether it be one of the world’s most energy-efficient supermarkets, which recovers heat from cooling and acts as a real-world showroom for energy efficiency technologies made by Danfoss, or the area’s pivotal district heating network.

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District heating is the secret

While the town’s plan to achieve climate neutrality by 2029 – one year ahead of the goal of the 100 European cities that signed up to the pledge – will be achieved through many changes, the key instrument perhaps is Sønderborg’s expansive district heating network.

“It’s important to have this district energy grid, which is, in my opinion, one of the secrets of the whole thing here,” explained Jürgen Fischer, president of Danfoss Climate Solutions.

District heating entails the centralised production of heat (and sometimes cold) which is then distributed to households through pipes – more efficient than decentralised systems of heating or cooling.

While cities like Berlin heat water to more than 90°C by burning coal, the Danish town’s grid operates at around 55°C.

“The higher you are in temperature, the more losses you have,” said Fischer. “As a rule of thumb: every ten degrees you go down, you save 30% energy.”

Linking “all the sources of energy and all the consumption of energy via this [efficient] district energy grid” was thus key to the town’s climate neutrality goals, he explained.

Being so low-temperature makes for an easier time using low-temperature waste heat, whether that be from the supermarket or Danfoss’ factory, Fischer told EURACTIV.

Earlier that day, Fischer held preliminary talks with a delegation from Indonesia. The country, one of the world’s most populous, is in the midst of creating a new capital from the ground up.

“They have a perfect opportunity to build new technology, new architecture, to do it [in a way that is] more climate neutral,” he added.

Sønderborg’s district heating grid spans from North, where the Danfoss factory is located, to South, to the town, on the island of Als near the German border. [Wikimedia Commons/Urutseg]

Onboarding populations

But the significance of Sønderborg’s proposed solutions may extend beyond just the technical: the municipality demonstrates the importance of mobilising local populations to support the often seismic changes required to rehaul a carbonised system.

One sentiment commonly expressed by the town’s residents is “green is good”, often said with a sense of pride. Sønderborgians are reminded of their town’s climate neutrality goal frequently by a dominant sphere-shaped representation of one ton of CO2 near the harbour.

“I think the population is proud, on board and also very curious and excited to be part of the journey,” said Fausing.

But fostering popular support requires work. “There is a certain support to people here,” he added. “Today you can find a stand, if you want to know as a citizen here, when can I get connected to district heating?”

“This community will try to help people to make the right decisions for them.”

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[Edited by Nathalie Weatherald]

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