Five new solar-bioenergy villages in Germany

Photo: Mengsberg

 

The solar district heating system in Mengsberg is the largest of the five new installations and supplies heat to 150 households. It was a complex and long planning phase which started in November 2012 when Viessmann staff paid a visit to the village, which is part of Neustadt in the state of Hesse. Almost exactly two years later, the next milestone was reached with the founding of the Bioenergiegenossenschaft Mengsberg (BEGM) association, now the operator of the renewable heating installation. In all, Viessmann spent 18 months on constructing a 3,000 m² solar field, a 1.1 MW wood-chip boiler and a 9-kilometre-long district heating system, including a heat interface unit for each of the 150 buildings. Solar energy is expected to provide 17 % of the heat in all homes.

 

German vacuum tube collector manufacturer Ritter XL successfully tendered for another three larger solar fields in bioenergy villages last year (see the following table). The largest, with 2,400 m² of collector area, was constructed in Randegg, which is part of the town of Gottmadingen in southern Germany. To clean bottles, local drink producer Ottilien-Quelle requires relatively large amounts of grid heat. The heat is supplied by Ritter-made Aqua Plasma vacuum tube collectors (link to https://www.solarthermalworld.org/content/germany-ritter-groups-eco-consequent-product-development) at 95 °C. These collectors possess two features that improve their efficiency. One is a silicon-oxide coating, applied to the glass tubes via a dry plasma process to raise the transmission rate from 91 % to 94 %. The other is a coating that covers the Compound Parabolic Concentrators (CPCs) to increase hemispherical reflectance (AM 1.5) from 84 % to 90 %. The woodchip boiler does not run in summer. 

 

Village and part of Germany	No. of grid-connected households	Length of district heating	Collector area	Collector type and supplier	Estimated annual yield	Estimated specific yield based on annual yield	Estimated solar share	Backup heat source
Liggeringen, south	90	5 km	1,100 m2	Flat plate collectors, S.O.L.I.D., Austria	470 MWh/a	427 kWh/m2a	20 %	Wood-chip boiler
Mengsberg, middle	150	9 km	3,000 m2	Flat plate collectors, Viessmann, Germany	900 MWh	300 kWh/m2a	17 %	1.1 MW wood-chip boiler
Randegg, south	150	6.6 km	2,400 m2	CPC VTC, Ritter XL, Germany	1,000 MWh/a	417 kWh/m2a	20 %	2 MW wood-chip boiler and 700 kW pellet boiler
Breklum, north	42	3.8 km	652 m2	CPC VTC, Ritter XL, Germany	289 MWh/a	443 kWh/m2a	8 %	Gas-fired cogeneration plant
Ellern, south	105	5.3 km	1,245 m2	CPC VTC, Ritter XL, Germany	555 MWh/a	446 kWh/m2a	15 %

List of the five new solar fields installed in bioenergy villages in Germany. The annual yield is maybe calculated with different tools in the five projects.

 

A growing number of German villages were using sunlight to produce heat, research institute Solites wrote in a press release last October. It also quoted Executive Board Member Thomas Pauschinger as saying that solar thermal installations were “being implemented in more and more energy villages as a reliable and economical heat source because such plants are a future-proof investment,” and were widely accepted by the local population. Today, villages could use solar energy to meet round about 20 % of their energy needs. Pauschinger added: “We expect solar thermal energy not only to meet summer demand, but to achieve higher solar shares via greater storage capacity in the future.”

 

Organisations mentioned in this article:

Solites: https://www.solar-district-heating.eu/de/startseite/