City Verl: Climate-friendly heating from the pipeline

Since 2009, the town of Verl has systematically pushed ahead with setting up and expanding a district heating network which is powered by a range of different heat sources. Both the town itself and a steadily growing number of private customers thus benefit from an efficient and climate-friendly heat supply.

In 2010, in order to replace the antiquated heating systems at a school complex in the town and at a neighbouring church property, they started to build a district heating transmission line that was approximately one kilometre in length in Verl. Prior to this, a feasibility study carried out in 2008 had revealed that a district heating network was the most sensible solution to cover the buildings’ heating requirements of around 5,000 megawatt-hours per year. Talks rapidly got underway with a private investor, who then quickly set up a satellite cogeneration plant in the direct vicinity of the school complex at the end of 2011. The farmer uses this unit to generate electricity from biogas, which he produces on his farm, situated at a distance of around 1.8 kilometres, and he then supplies the district heating network with the waste heat from the cogeneration unit.

Engine for progress:

  • Annual reduction in CO2 emissions of 2,700 tonnes
  • Climate-friendly heat supply using 75 per cent bioenergy
  • Energy-efficient system thanks to the high standard of insulation

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Photo: Energieagentur Lippe GmbH / Christoph Frömming

Schematic illustration of the biomass heating plant in Verl. The boiler shown has a thermal output of around 1.7 megawatts. The heating plant is currently fitted with an additional boiler with an output of 800 kilowatts.

Slow and steady wins the race

As a result of the positive experience gained and since there was extra capacity, the district heating network was opened up to private consumers along the route of the pipeline. In the course of restructuring the road through Verl, carried out by road construction company Straßen.NRW, it was then decided to seize the opportunity of extending the district heating network all the way to the town centre – a distance of more than 2.5 kilometres. After that, the district heating system was made available to another residential estate, which was won over to district heating with a connection rate of over 60 per cent. This constant expansion has ultimately resulted in a current total of 160 private consumers connected to the network. One key element of this success was that residents were given concrete details on the potential heat output for each stage of the network expansion through individual surveys and information meetings. On the part of the town, there was a “carer” responsible for this distribution of information; this individual represented the “face” of the initiative and thus built trust.

Long-term planning

Right from the start, a biomass heating plant with a thermal output of 1.7 megawatts was planned as a heat generator in the district heating network. Wood chips from local wood residues collected during road verge maintenance and from gardening and landscaping companies are used as a source of energy. Fortunately, during the construction of the biomass heating plant, relevant components such as the buildings, fuel feed and flue gas purification were already designed in such a way that a second wood-fired boiler with an output of 800 kilowatts could be easily integrated, and this was the case two years later in the course of the expansion of the district heating network. Over time, three more cogeneration plants powered by natural gas were connected to the network; the electricity they produce is either used directly by municipal institutions or fed back into the grid when excess is generated. The waste heat from the cogeneration plant is also fed back directly into the district heating network.

Streamlined for efficiency

In order to reduce heat loss from the district heating network, which now covers a distance of almost ten kilometres, great emphasis was placed on the high insulation standard of the pipelines. This limits the heat loss to around 10 per cent.

Photo: City of Verl

“Verl is getting in shape for the future and focusing on renewable energy. Our sustainable heat supply is currently enabling us to reduce CO2 emissions by 2,700 tonnes a year. And this is increasing all the time because the expansion of the system is ongoing. We are thus involved in climate protection at a local level.”

Winfried Egbringhoff, Verl Project Manager, Civil engineering branch

Partners and sponsors

  • Versorgungs- und Bäderbetrieb der Stadt Verl
  • Ministerium für Klimaschutz, Umwelt, Landwirtschaft, Natur- und Verbraucherschutz (MKULNV)
  • KfW-Bank

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