Silkeborg's solar district heating to cover 20 % of heating demand

The Danish town of Silkeborg now holds the record for having the world’s largest solar heating system. The SDH plant of 156,694 m² came online as scheduled in December 2016 after only seven months of construction. Municipal utility Silkeborg Forsyning intends to use the harnessed solar energy to meet around 20 % of the annual heating demand of the 21,000 plant-connected users. The solar field was divided into four subfields to make it possible to set up the installation and hydraulics systems on this irregularly shaped piece of land (see photo).

Name of Project / installation site

Silkeborg Forsyning



Start of operations

December 2016


District heating

Gross collector field size

110 MWth, 156,694 m²

Storage size

Short-term storages with a total volume of 32,000 m3, no seasonal storage available

Supplied process / network

Supply of 21,000 users

Expected specific solar yield per year

511 kWh/m2 (80,000 MWh per year)
The yield is higher than at Vojens, the second largest solar district heating plant worldwide with 400 kWh/m2, because Silkeborg has no seasonal storage and a smaller solar share

Predicted solar share

Around 20 % of the total heating demand of app. 425,000 MWh/year

Customer / operator

Silkeborg Forsyning, Denmark

Planning / construction / commissioning

Arcon Sunmark, Denmark

Manufacturer of collectors

Arcon Sunmark, Denmark


Silkeborg Forsyning A/S

0045 89 20 64 00

More information


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