Stadtwerke Flensburg reduces CO2 emissions: On course to climate neutrality!

Stadtwerke Flensburg reduces CO2 emissions: On course to climate neutrality!

Stadtwerke Flensburg is embarking on a sustainable course and will have reduced CO2 emissions by 10% in 2024 compared to the previous year. An impressive 463,508 tons of CO2 were emitted - this corresponds to around half of the CO2 footprint of a Flensburg city resident. This result is clearly due to the exchange of coal for natural gas, which reduces emissions by around 40%. But the journey to climate neutrality is not over yet. Loud NDR Flensburg is still slightly above the reduction path set out in the transformation plan in order to become climate neutral by 2035.

An important step on this path is the operation of a second gas and steam turbine power plant since summer 2023. In the future, the first large-scale heat pump that uses Förde water is scheduled to be started in 2027; another facility is planned for 2031. However, there are also challenges: the planned heat pumps will only be able to deliver around half of the power required in winter and will have to be throttled back in severe frost.

Challenges and solutions

The municipal utilities will soon have to resort to green hydrogen, which is unlikely to be available from Denmark before 2032. In addition, a conversion of the district heating network is necessary in order to be able to optimally use the energy from the large heat pumps. In the future, thicker pipes will transport district heating at a temperature of 90 instead of 120 degrees. Flensburg municipal utilities have the ambition to replace coal and gas ten years faster than planned – a thoroughly ambitious undertaking.

The plan also includes the implementation of one of the world's largest systems for using thermal energy from the fjord, which will heat a fifth of the city from 2027. The first climate-friendly substation in Schleswig-Holstein is also being built by SH Netz and is scheduled to go into operation in mid-2026.

Technical considerations

The challenges in energy production relate not only to the change in energy sources, but also to the refrigerants used. There are both synthetic and natural refrigerants, each with their own advantages and disadvantages. Ammonia, for example, is a necessary refrigerant, but carries risks such as high toxicity. On the other hand, for example, CO₂ was used as a refrigerant in Esbjerg, but is not suitable for Flensburg due to the return temperatures being too high. In this context, reference is also made to isobutane, which could in principle be used, but has not yet been used in Flensburg.

The Study by the Fraunhofer Institute for Solar Energy Systems deals comprehensively with the transformation paths to climate neutrality in Germany. She emphasizes that technical CO2 sinks and consideration of different sectors such as energy, industry and transport are essential for the success of the energy transition. The future of Flensburg seems to be associated with many challenges, but also great opportunities.