Mid-November was a turbulent week for the heat transition in Germany. On 21 November, one of the largest solar process heat plants in Germany went into operation – a 1.5 MW vacuum tube collector field for a gas pressure regulating system. In the same week, HeatExpo, a trade fair specifically for commercial heat, was held for the first time in Dortmund with around 100 exhibitors from 12 countries. At the same time, the German Ministry of Finance was forced to announce a budget freeze, which also stopped applications for two funding programmes that are important for the commercial heat transition: Federal Funding for Efficient Heating Networks (BEW) and Energy Efficiency in the Economy (EEW). It is hoped that applications will be possible again in just a few weeks.
Photo: Ontras Gastransport GmbH
The 1.5 MW plant impressively demonstrates that the commercial heat transition in Germany can be organized locally. The 165 collector panels of 13 m² each were sourced by Akotec Produktionsgesellschaft, a manufacturer in the same federal state of Brandenburg. The project developer was the German company Enertracting supported by the University of Kassel in central Germany. Enertracting already had experience with solar heat for gas pressure regulating systems, but on a much smaller scale. The company´s first solar heat system for a gas company was installed already in 2012 with a capacity of 0.2 MW.
Ontras Gastransport is the owner and operator of the 1.5 MW solar industrial heat plant in Kienbaum. There, Ontras takes gas into its network from the interconnected European system. Whereas long-distance gas transportation requires high pressures, the distribution pipelines are operated at lower pressure levels. Reducing the pressure causes a significant temperature drop, which would lead to icing of the pipes This can damage the pipes and fittings. To avoid such situations, gas pressure regulating systems are heated, for example, by a gas boiler, which usually consumes 0.1 to 0.2 % of the transported gas.
The first contact between Ontras and Enertracting took place back in 2019. Implementation was then delayed several times due to the turbulence on the gas market caused by the pandemic and the Russian war with the Ukraine.
Ontras wants to use the solar heat plant in a heat-led manner as far as possible. “We operate our network in such a way that it takes on exactly the amount of gas in Kienbaum that can be completely preheated using solar thermal energy without also using the gas boilers. This enables us to maximize CO2 avoidance in gas preheating”, Ontras Managing Director Ralph Bahke is quoted as saying in a press release.
Company spokesperson Dr Ralf Borschinsky does not clearly confirm whether Ontras is planning any further solar thermal systems for its gas regulation plants: “We are currently planning CO₂-reducing measures for several systems, but these are still in the final coordination phase, so I can’t give any more detailed information on this yet.”
| Gross size of solar thermal collector field | 2,145 m² |
| Solar thermal capacity of collector field | 1.5 MW |
| Collector type | Heat pipe vacuum tube collectors of the type Mega with 13 m² each |
| Supplier of collectors | Akotec Produktionsgesellschaft, Germany |
| Temperature of supplied solar heat | 60 °C |
| Project developers | Enertracting supported by the University of Kassel, both Germany |
| Owner and operator of solar collector field | Ontras Gastransport, Germany |
| Estimated annual yield of solar collector field | 850 MWh/a |
| Specific annual yield | 395 kWh/m²a |
| Total investment costs of solar plant including installation, land property, compensatory measures, fulfillment of official requirements, integration into the existing system | Around EUR 3.5 million |
| Level of subsidy | 45 % of the investment costs from Energy Efficiency in Industry funding scheme |
Key figures for the 1.5 MW solar heat plant in Kienbaum, Eastern Germany. The system is operated without a storage tank because the solar heat is continuously used to preheat the gas. Source: Ontras / Akotec
Solar heat was well-represented during the first HeatExpo in Germany
The heating transition in Germany needs new platforms. The fair in Dortmund in central Germany has created a new trade fair format under the title HeatExpo: a B2B platform for representatives of municipal utilities and energy suppliers. Solar thermal energy was well represented at the three-day event.
Akotec Produktionsgesellschaft was among the exhibitors sharing a booth with the German chiller manufacturer Fahrenheit, whose sorption chillers can also be driven be solar heat.
Aalborg CSP introduced its new cover concept for multi-functional storage tanks (see photo), which was used among others in Høje Tåstrup near Copenhagen. From below, the insulation is separated from the water layer by diffusion-open geomembranes. At the top, the rainwater is additionally channelled via a stone layer to a depression, where pumps are located that drain the rain water away from the storage cover. Senior Vice President Jes Donneborg confirmed that Aalborg CSP is currently participating in planning around 10 seasonal storage facilities in Germany alone and almost the same number outside Germany. Not all of these have solar thermal systems as the primary heat source, but will be used for storing waste heat or power to heat often via heat pumps.
EAG Energieanlagen Greifswald presented its transfer station (balance of plant) for what is currently Germany’s largest solar district heating plant in Greifswald. The company has tendered for the balance of plant for the even larger 45.5 MW SDH plant in Leipzig, Germany. The process is still ongoing. Managing Director Michael Lüdeke said that HeatExpo exceeded his expectations: “We were able to acquire new customers thanks to the extremely knowledgeable audience,” he was quoted as saying by the fair organizers in their press release.
Jes Donneborg, Executive Vice President of Aalborg CSP, with its new cover concept for pit heat seasonal storage tanks during the HeatExpo in Dortmund, Germany Photo: solrico
