The landmark war ruins of the Hamburg-Wilhelmsburg flak bunker (Friedrich Tamms, construction period: end of 1942 ' mid 1943) was redeveloped in 2012 and became the energy centre for the decentralised heat and power supply of the neighbouring residential area. As part of IBA-Hamburg GmbH, the project converts up to 85% of its heat from renewable sources of energy which saves approx. 95% in CO2.
The solar casing, which as a steel structure ' detached from the contour of the building ' is drawn across the roof and southern façade, is a far-reaching visible element for its transformation from a military construction to the symbol of renewable energy supply in Hamburg. The thermal power of its collectors is 750 kW; the output of the photovoltaic installation on the southern side is approx. 100 kWpeak.
A large-scale buffer storage facility, whereby the thermal generating capacity to be installed could already be greatly reduced, is the centrepiece of the energy bunker. The large-scale buffer storage facility holds a total of 2,000,000 l of water and is in the central room inside the bunker, which came into existence through explosions to the internal structure shortly after the end of the war. The storage facility is fed by the heat of the solar thermal installation, industrial waste heat, a biomethane gas-driven combined heat and power unit and a wood combustion system.
The bunker has been made accessible to the public as a memorial and landmark monument (in March 2013), which is in the middle of a residential area, through a new development and the opening of a café in one of the anti-aircraft turrets at a height of 30 m.