In Senftenberg, Brandenburg, the largest solar thermal plant of Germany with 8 300 m² collector was inaugurated. It should deliver 4 GWh in the district heating network of Senftenberg,
25 000 inhabitants, every year.

At the inauguration event on 23rd of September, the utility ‘Stadtwerke Senftenberg’ as operator and Ritter XL Solar GmbH as manufacturer and planner of the collector field could already look back on more than four weeks of successful operation. Thanks to the late summer weather, the plant could already deliver more than 20% of its predicted yearly yield, said Detlef Moschke, director of the utility. ‘Already during the weekend from 26th to 28th of August, we measured 85,6 MWh supplied. It is enough to cover the basic load of 3 000 households in Senftenberg’, said Moschke.By such summerly conditions, the solar plant is the only heat supplier feeding in the net. Via the newly built heat exchanger, the heat is normally fed directly into the feed-in pipe of the district heating system. The CPC evacuated tube collectors deliver temperatures from 85 to 110°C. In case of bad irradiation conditions at the beginning and end of days or in case of cloudy sky, the plant can also feed in the return pipe of the district heating network, where lower temperatures and pressures have to be overcome.

The collector field of Senftenberg, unlike some other smaller solar projects from Ritter XL, is hydraulically separated from the district heating net. Even if the collectors are operated with water without any antifreeze fluid, two heat exchangers separate them from the district heating net. Rolf Meißner, director of Ritter XL explains that the hydraulic separation is simply a precaution due to the insufficient water quality in the district heating of Senftenberg.

The area of 2,2 hectares where the plant is built is located on a previous waste disposal site from the City of Senftenberg, where the recultivation process ended last year. It was a chance for Senftenberg that a strand of the district heating net is passing directly along the site. Like this, a short transmission pipe of a few hundred meters is enough to connect the solar plant with the district heating network.

The head of the energy policy department in the Federal Ministry for Economic Affairs and Energy Thorsten Herdan underlined at the inauguration event that the solar thermal plant of Senftenberg is not a research or demonstration plant but a commercial plant that has been calculated according to economical criteria. As an emblem of the solar district heating technology, the plant will be observed with attention from Berlin, said Herdan. ‘The monitoring of this plant is extremely important to us. Show us with this plant, how it can be done’, called Herdan to the public.

Important facts about the solar thermal plant in Senftenberg
Total area: 2,2 ha
Collector field: 170m * 120m
Gross collector area: 8 300 m²
Number of evacuated tube collectors: 1 680
Total length of the pipes: 6,5 km
Calculated yearly yield: app. 4 GWh
Operator: Stadtwerke Senftenberg
Manufacture and planning of the collector plant and regulation: Ritter XL Solar GmbH
General contractor: INTEGRAL Projekt GmbH & Co. KG, Cottbus