The overall district heating system benefits significantly from the flexibility of these fossil-based boilers.
the next few years, large electric boilers will replace some of the larger oil-fired boilers.
Copenhagen walked the talk! Is the above brief description of the possible development of a district heating system just theory? No – if we briefly look at the district heating system in the western part of Greater Copen- hagen, the historical development here has been as follows. In the 1960s and 1970s, 19 local, independent district heating companies comprised the district heating system. The district heating supply was based on fuel oil or coal-fired boilers and small local waste incineration plants. In the late 1980s, the many district heating companies were connected to a central district heating transmission network (VEKS – www.veks.dk), which supplied surplus heat from large central combined heat and power plants (coal-fired) and large waste incineration plants to the local distribution networks.
Conclusion If there had not been an expansion of district heating in the western part of Greater Copenhagen based on coal and oil- fired boilers 50-60 years ago, the foundation would not have been laid for a well-functioning, energy-efficient district heat- ing system in the western part of Greater Copenhagen in 2025, which will be based on 100% CO2-neutral heat production. The next step is to reduce biomass consumption and utilize more surplus heat from future sources – such as CCS/U – more about this can be read in this article describing Copenhagen's heat plan up to 2050.
At the same time, the small local waste incineration plants were closed, and the local coal-fired boilers were shut down. The central boilers in the local district heating companies were retained – over time, fuel oil was phased out and replaced with light gas oil. Some boilers were equipped with dual-fuel burn- ers so that they could use both gas oil and natural gas. Today, only 2-3% of the district heating demand in the western part of Greater Copenhagen is covered by produc- tion from oil and natural gas-fired boilers, while the remain- ing 97-98% is covered by surplus heat from combined heat and power (CHP) plants, which now use sustainable biomass, surplus heat from waste energy plants, and surplus heat from industry. The CHP plants were converted from fossil fuels to sustainable biomass between 2008-2020. Today, the originally oil-fired boilers still have a significant func- tion in the overall district heating system. Their role today is not to cover the entire heat demand but solely to serve as peak and reserve load when it is very cold – or when the large, CHP plants or waste-to-energy plants cannot meet the heat demand. Over
The Copenhagen system demonstrates the stepping stones used back then. Now we need to move ahead stepping on similar stones without building new fossil-based production capacity. So, starting the green transition by connecting fos- sil-based customers to a fossil-based district heating system can be the first step on the "green journey." Let’s not sit around waiting for all conditions to be perfect; there are several step- ping stones, and we gather knowledge by every step we take.
For further information please contact: Lars Gullev, lg@veks.dk
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