The district heating operator in Berlin-Adlershof BTB enables the connection of a solar thermal plant and an innovative plus-energy house concept for a district via net-metering contract.
The specificity of the business model currently appears very clearly. The 613 m² evacuated-tube collectors from Ritter XL located on two from the five buildings already produce heat since May but the apartments in the buildings are not occupied yet. Still, the future occupants benefit from the heat produced now since the BTB (Blockheizkraftwerks-Träger- und Betreibergesellschaft mbH), operator of the district heating network, has offered the housing company a special deal: every kWh of solar heat which is not needed in the buildings is fed-into the district heating network and accounts for one kWh that will be delivered by the district heating network in the winter.This is a win-win situation. The evacuated-tube collectors produce more over the year than the heat consumption of the five buildings, even if only two of the roofs are covered. The surplus heat is free for the district heating operator. On the other hand, the housing company has guarantee that it does not need to buy heat and can define a relatively cheap fixed rent including heat costs. Thanks to the fact that the network is used as storage, only 10 m³ of storage volume is needed for the five buildings. As soon as these are loaded, the additional solar power is fed into the district heating network.