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Former Nazi bunker transformed into green energy power plant


February 11, 2014

The Energy Bunker was originally constructed in 1943 to serve as a Nazi anti-aircraft bunker during WWII (Photo: IBA Hamburg GmbH / Bernadette Grimmenstein)

The Energy Bunker was originally constructed in 1943 to serve as a Nazi anti-aircraft bunker during WWII (Photo: IBA Hamburg GmbH / Bernadette Grimmenstein)

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Energy and utilities company Hamburg Energie has joined forces with IBA Hamburg to transform a former Nazi anti-aircraft flak bunker into a green energy power plant. The Hamburg-based "Energy Bunker" has already begun producing energy for the local community, but once running at full capacity will provide up to 3,000 homes with heating, and another 1,000 homes with electricity.

Originally constructed in 1943 to serve as an anti-aircraft bunker, complete with gun turrets, the 42 m (137 ft) -high building also sheltered local people from Allied bombing raids during WWII. Though the British Army made an attempt to demolish the building on the war's close, blowing up its massively thick walls was deemed too dangerous to nearby buildings. The British ultimately settled on destroying much of the interior, and the bunker remained in this neglected state for over 60 years.

Plans to transform the building into a green energy hub first arose in 2006, with the renovation proper commencing in 2011, following extensive safety tests. The total cost of the project came to €26.7 million (roughly US$36.5 million) and was funded by both the the European Regional Development Fund (ERDF) and the Hamburg Climate Protection Concept.

The Energy Bunker is outfitted with several sustainable technologies. The main feature is a 2 million liter (528,000 US gallon) water reservoir that acts as a large heat store and plugs into the existing Reiherstieg district heating network. The reservoir itself is heated by several methods: a biomass power plant and wood chip burning unit which feed into a large boiler, a solar thermal array installed on the roof of the bunker, and waste heat produced by a nearby industrial plant.

A large photovoltaic system is installed on the south-facing facade of the building to produce electricity, and the wood chip burning unit is also used to produce electricity. A peak-load boiler and large battery array ensure that the energy output is kept steady at all times.

In addition to the production of green energy, Energy Bunker also contains a war memorial, cafe, and visitors center, where people can learn more about the building's history.

Source: IBA Hamburg

About the Author
Adam Williams Adam scours the globe from his home in North Wales in order to bring the best of innovative architecture and sustainable design to the pages of Gizmag. Most of his spare time is spent dabbling in music, tinkering with old Macintosh computers and trying to keep his even older VW bus on the road. All articles by Adam Williams

I wonder if they left all the historical markings. I guess the Nazi's made all sorts of structures that retain them but still. . .


If they could only extract energy using Godwin's Law! :)

Jon A.

Godwin could not win arguments without hobbling his opponents.


With the energy required to gather the wood chips I really don't see the burner as being greener than pipe delivered fuels like oil and natural gas.


@slowburn, Amazed by your comment, you must be deep in oil business and global warming denial. Wood chips are either left overs form wood production or thinning wood from the forest, both realized in a nearly closed CO2 process. Indeed transport might adds some negative points to it. Comparing with oil and natural gas, transported around the globe, only adding CO2 into the atmosphere, that's peanuts.

Ramon Verhoeven


I rather doubt any historical markings survived the sanctified scrubbing that has been done already, and continues to be done. Oh, maybe, "Achtung! Wash hands here!" or "Achtung! Throw garbage here!" survived. To be safe, one can dwell to the heart's content on say, the Roman conquest of Gaul... or

"I don't do history often, but when I do, The Peloponnesian Wars, are not Greek to me. Stay safe my friends."


Anyone interested in doing this kind of work should also look into adding phase change salt heat storage. Phase Change Salts are capable of storing a far larger amount of energy per unit volume than water and they absolutely will not "wear out", are cheap, stable, and relatively non-toxic. Water would still be the best & cheapest heat transfer media for initial heat gain and also for transporting the heat gained to storage and users. It is practical to produce domestic water & space heating as well as process heat flows. Phase Change Salt heat storage can compactly store enough heat to span most any cold & cloudy period to get to the next sunny heat gain period and at a price that fossil fuels can never compete with.


Ya, nice thing, thou not realy overwhelming. Esthetically questionable and technicaly nothing realy new. Still: For sure much better than just keeping that rotten concrete block.

Anders Knoll

@ Ramon Verhoeven Wood is being harvested in in the USofA to fuel electrical generation plants in Europe so clearly the transportation is significant. Besides leaving the wood chips on the forest floor in highly beneficial. In many places gathering wood is forbidden because the wood on the ground provides the nutrients for the growing trees.


@slowburn, partly wright but: I think you have a typical example of wrong economics. Are the US not capable to use their woodchips in making elektricity? Or might oil/gas be cheaper because of subsidies (read tax breaks/investment subsidies) for big oil ? If the real costs of coal/oil/gas would have to be paid, including the pollution factor, I think the US would use more of the woodchips. Europe has a carbon tax system that pushes to more greener energy and away from oil. Time for the US to get into this direction and take their responsibility towards global warming. Do you suggest bringing woodchips back into the forest, you cant be serious ? Here we leave a sufficient amount of woodchips/trees and dead trees/meterial behind in the forest. Woodchips/sawdust from industry is definitely not needed for that.

Ramon Verhoeven

9,125 dollars per home not bad but why wood chips typically shipped in from outside the nation when you have the sewage from the homes to use and you are making fertilizer at the same time. This is just more government puedo green energy pork feel good BS.


@ Ramon Verhoeven

First. Burning wood as an industrial energy source as been tried before; it was an ecological disaster which is why burning wood to make Iron and glass was banned.

Second. How much wood scrap and sawdust do you think industry makes?

Third. What would it take to convince you that the global warming is a result of natural processes not the actions of man? For me it was looking at three charts next to each other: Average global temperature over the 20 century. Atmospheric C02 over the 20 century. Solar output over the 20 century. But I am automatically suspicious of anything that the solution proposed is to give a greater portion of my earning to the government.


Germany is a beautiful country, and the people are very neat, and clean, and friendly. I spent 2 years in Germany, and loved meeting the people, and getting to know the country. We all know that Germans, will engineer a project to the best of their ability. This project is a fine example of how they turned a structure into a viable asset, for the community. BRAVO.

alfred knows
Talk about turning swords into plowshares! It makes sense as these bunkers were made to be bomb proof and the cost and energy required to dismantle a bunker like this is prohibitive. Jim Sadler


I don't think you know much about the wood industry because there is plenty chips and waste. Trees are tubular most planks are flat. Even making plywood and chipboard creates plenty waste. Wood chips are sold by many milling and forestry companies to monetise that waste.

In the old days wood was burnt incorrectly with not enough oxygen leading to plenty carbon monoxide emissions Nowadays with forced draught burners and fluidised bed systems burning is quite clean.

Trees also grow far faster than oil takes to form so it is far more renewable. I won't go into your disbelief of global warming. All I will say is that oil is finite. So we should be saving it however we can.

Leaving wood waste in the forest leads to decomposition and the release of methane which is a more potent greenhouse gas than the carbon dioxide emitted from combustion.

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