Wilhelmsburg’s former air raid bunker has been transformed into a symbol of the “Renewable Wilhelmsburg” Climate Protection Concept. Having languished almost unused since the end of World War II, the monument has now been renovated during the IBA Hamburg and converted into a power plant using renewable forms of energy, with a large heat reservoir. This supplies the Reiherstieg district with climate-friendly heat, while feeding renewable power into the Hamburg distribution grid.
The air raid bunker on Neuhöfer Strasse was built in 1943 to demonstrate the supposed valour of the home front. Thousands of people sought shelter from the allied bombing raids in two such bunkers, one in Wilhelmsburg and the other in St Pauli. With its flak towers, the bunker also formed part of the German war machine. In 1947 the interior of the building was completely destroyed by the British Army in a controlled demolition. Six of the eight floors collapsed, and the rest was too dangerous to access. Only the outer shell of the structure, its walls up to three metres and its ceilings up to four metres thick, remained almost intact. For over sixty years, further use of the building was restricted to a few adjacent areas.
Now the bunker, which had been in danger of collapsing, is being renovated and preserved as a monument as part of the Internationale Bauausstellung IBA Hamburg (International Building Exhibition). The history of the bunker and the former residents of the Reiherstieg district are the focus of an exhibition in and around the building. The <vju> Café and its 30 metre high terrace offer a unique view over Hamburg, the city's harbour, and across to the Harburg Hills.
Monument and Energy Bunker
With a solar casing on its roof and southern side, the “Energy Bunker”, visible from a distance, marks an important milestone on the road towards supplying the Elbe islands with renewable forms of energy. By using, in an intelligent way, a combination of solar energy, biogas, wood chips, and waste heat from a nearby industrial plant, the “Energy Bunker” is set to supply most of the Reiherstieg district with heat, while also feeding renewable power into the electricity grid. When completed, the bunker will generate approximately 22,500 megawatt hours of heat and almost 3000 megawatt hours of electricity. This meets the heating requirements of around 3000 households and the electricity needs of around 1000 homes, equalling a carbon saving of 95 per cent, or around 6600 tonnes of carbon per year. As a local power plant, the “Energy Bunker” represents a decentralised energy policy that creates local jobs and income.
Innovative Technology in a Smart Network
At the heart of the project is the large heat reservoir built inside the former air raid bunker. In the years to come it will transform the building into an “Energy Bunker” capable of supplying a district covering an area of more than 1.2 square kilometres (120 hectares), thanks to the integration of different types of environmentally friendly heat and electric power units. The project's most innovative feature is its large-scale buffer storage facility, with an expected total capacity of 2 million litres (2000 cubic metres). This is fed by the heat from a biomethane-fired combined heat and power unit, a wood combustion system, and a solar thermal unit, as well as the waste heat from an industrial plant. The buffering effect of the storage facility will result in a significant drop in the thermal generation performance, from 11 to 6.5 megawatts, enabling the economic use of renewable energy as part of the heat supply concept.
The concept is the first of its kind in the world, advancing knowledge about the practicality of the control and hydraulic technologies used. In addition, an extension of the project is currently being researched by SMART POWER Hamburg. In future excess wind power from northern Germany could be transformed into heat in the reservoir, or heat from an extra combined heat and power unit could be fed into the reservoir at times of low wind and sunshine, and used to generate electricity.
The total cost of the project comes to around € 27 million, of which approximately € 11.7 million was spent on the technology and the heat grid (excluding the solar casing). This money was boosted by the European Union, with around € 3.1 million from the ERDF (European Regional Development Fund). The solar casing was also supported by funds from the Hamburg Climate Protection Concept.
Overview of the Power Supply
- Efficient and large-scale use of renewable local energy
- Simultaneous generation of electricity and heat through combined heat and power, based on biomethane
- Storage of (heat) energy, to compensate for the non-controllable solar energy and to increase power generation in the combined heat and power unit, in a large reservoir, with a capacity of approximately 2000 cubic metres, within the bunker
- Use of solar energy in a large-scale unit covering around 2000 square metres
A Café with a View: <vju> Café
One of the bunker’s flak towers houses the <vju> Café and its remarkable panoramic terrace. This cantilevered platform, which runs around the whole building at a height of 30 metres, offers 360° views over almost all of Hamburg. From up here, it is clear just how fascinating and varied Wilhelmsburg really is. What's more, the second major project to be carried out as part of the exhibition theme “Cities and Climate Change” is almost at eye level – the “Georgswerder Energy Hill”, with its giant wind turbines and Hamburg's largest open photovoltaic system, lies to the east of the “Energy Bunker”.
2006–2009: concept development
2010: structural investigations and urgent safety measures
March 2011: start of redevelopment work and clearance of debris from interior
- October 2011: restoration of façade
- Spring 2012: start of construction work on energy centre (HAMBIRGENERGIE)
- October 2012: start of construction work on solar casing (HAMBURG ENERGIE)
- October 2012: start of heat supply
- March 2013: completion of building
- 23 March 2013: opening of <vju> Café and exhibition
- 2015: planned project completion of the heat grid expansion
This project is supported by:European UnionEuropean Regional Development FundInvesting in Your Future
Free and Hanseatic City of Hamburg
Coordination Center for Climate Issues
Built in: 1943
Demolition of the interior: 1947
Beginning of conversion: 2010
Floor area: 57 x 57 m
Height: 42 m
Documentation centre with café: 880 m² + 540 m²
Energy centre: 5625 m²
Solar panel façade:
Approx. 1600 m² (south side)
Photovoltaic system: Approx. 1100 m² (roof)
Hot water tank: 2000 m³
Heating for 3000 and electricity for 1000 households, CO2 saving ~ 95 %