Sonderborg – The future zero carbon city


The 76,000 citizens of the little-known Danish municipality Sonderborg act, while politicians talk and climate change is accelerating. They share the vision of ProjectZero and have committed themselves to make Sonderborg zero carbon by 2029.

Sonderborg is a picturesque municipality close to the water and the German border, and it wants to prove that climate neutrality is achievable when cities take decisive action and ensure citizens and companies participate in finding new solutions and retrofitting society’s energy consumption and generation.

The ProjectZero visionary project is focused on transitioning Sonderborg into a ZERO carbon community, based on sustainable growth and creating new green jobs. Energy efficiency and energy from the area’s own renewable sources are the key means to turn the vision into reality. New thinking is essential and public policy and investments fuel the transition.

In SmartEnCity, Sonderborg seeks to

  • Demonstrate ambitious electrification of Sonderborg’s Roadmap2020 and Roadmap2015, including integration of rooftop PV power production
  • Integrate local green transit mobility solutions
  • Energy retrofitting existing housing association buildings in close cooperation with tenants
  • Engage the citizens as co-designers of the Smart Zero Carbon Sonderborg ambition based integrated solutions, comprehensive learning and the introduction of new ICT based energy information.

Renewable energy in the city

Sonderborg town is supplied with district heating from the Sonderborg District Heating company. The company has a mix of heating sources, including waste incineration, geothermal, solar and biomass, and natural gas for peak loads. Waste incineration is only counted as 50% renewable according to national standards, otherwise the city is mainly heated through renewables. There are five district heating companies supplying heat to the Sonderborg Municipality outside of the town, all with varying degrees of RES. Among these heating sources are solar, heat pump, gas turbine, immersion heater, and a planned straw-fired boiler that will be operational in 2019.

Sonderborg Municipality produced 47GHh electricity from RES in 2016, which is 6 GWh less compared to 2015 mainly because of less wind. The goal for the Sonderborg area is to become CO2 neutral by 2029, which is planned in combination of reducing CO2 emissions by 50% compared to 2007 levels and covering the remaining consumption with 100% RES. Several larger companies along with private households have installed PV panels to cover their own electricity consumption, selling any surplus production to the grid.

Main Project Results in Sonderborg:

                                                    Table: Sonderborg impacts at city level. 

Energy retrofit 

  • 117 buildings consisting of 2,022 dwellings including the following measures: Façade insulation, new windows, new ventilation systems, heating automatic, LED, PV roof integrated panels
  • Additional 1,639 apartments with PV/battery systems
  • New ESCO finance schemes demonstrated
  • Online (CIOP) monitoring system
  • The total investment of the district = 11,517,000 EURO
  • 2,980 MWh in energy savings and 485 t CO2 emissions reduced due to district renovation in total.
  • 44 biogas busses an investment decision made by Sonderborg Municipality and Sydtrafik (2017) plus 24 e-mobility charging points established - now a catalyzer for e-mobility
  • Catalyzing Construction of two gas charging stations in cooperation with Nature Energy
  • Enabling two biogas plants (in operation by 2020, 2022)
  • Enabling Sonderborg to become a pioneer in separation of waste fragments (Sonfor, 2020)
  • Catalyzing the decision of 5 new e and 5 new gas utility
  • waste collection trucks (Sonfor, 2020)
  • Circular economy strategy for Sonfor (2020)
  • Citizen engagement in waste management
  • 2,406 t CO2 yearly saved due to the replacement of diesel busses
  • Sonderborg’s smart city portal (CIOP) replicates the scheme and functionalities created for Tartu’s one. A total of 5467 devices have been connected to the platform.

Other Aspects

  • Launch of Sonderborg's Roadmap2025, an integrated energy planning process to remove 392,000 ton CO2.
  • Citizens are participating in the climate transition journey; a majority have approved almost all the investment measures presented and citizens are actively implementing own initiatives and want more initiatives

For more details on the interventions, click here: Smart Solutions for Sonderborg