A neighbourhood running on water: energy efficiency in the middle of a world heritage site

Bamberg , Germany Environment and Resource efficiency
Responsible Housing Award


When acquiring the “Upper Mills” neighbourhood in the 1970s, Joseph-Stiftung was pursuing the values of sustainability and economy. This guided the idea was to use the river as source of energy as was done in the 12th century. However, it was a major challenge to transport the concept of using water power into the 20th and 21st century with all the challenges and requirements of a modern world. The project turned out to be even more challenging since the neighbourhood is located in the historic centre of Bamberg in the middle of a world heritage. It was therefore necessary to realise the project without distracting visitors’ views from the historic sites i.e. no construction or technical system should be visible. Thus the whole construction had to be developed under water, a complete innovation at that time. Due to these requirements, only about half of the river water flows through the turbines which means an absorption of 27.5 m³ of water per second. It is still an objective to constantly minimise the ecological footprint of the neighbourhood and implement ecological improvements in that area. Hence, it was agreed from early on, that the project should also serve an educational purpose and teach the next generations about sustainability and mindful energy consumption.


Before Joseph-Stiftung acquired the area in the 1970s for renovation, it was an ordinary area in the historic town centre of Bamberg. The buildings were in dire need of renovation and the energy provision was as ordinary as any quarter’s at the time. Joseph-Stiftung aimed to improve the overall situation in the neighbourhood and to live up to its four principles and business values: First of all, Joseph-Stiftung has a responsibility to pursue its social, Catholic mission.
Second, it is key to the activities to be innovative and open to new ideas which continuously evolve. Third, it is essential to choose a sustainable approach and preserve what has proven successful for our customers, employees and business partners. Finally, it is important that social and environmental responsibility run parallel with economic values. Under these conditions, the concept of the “Upper Mills” was born and the goals set for the development of the neighbourhood.
These proven concepts and measures can be and are duplicated in
other neighbourhoods where feasible.

Issues tackled

Joseph-Stiftung staff remotely controls the “Upper Mills” system and monitor and analyse system data. A high level of problem-solving competence and creativity was needed to reach their goals. Excellent communication skills were necessary in order to work with researchers, authorities, legal frameworks, developers of technology, preservers of flora and fauna etc., especially
within the framework of a historic town centre with strict preservation regulations. Improvements are always going on in order to meet new requirements, improve performance and better protect the environment. Constant training and education of staff is needed. JosephStiftung decided to keep the project in its own hands, so that all assets belong to the company and are operated and administrated by the company or one of its subsidiary companies.


Apart from realising Europeʹs first underground run-of-river hydropower-plant, Joseph-Stiftung’s goal is to constantly improve and optimise construction according to new developments and research results. In addition, further measures in terms of energy-efficiency are taken in the neighbourhood or implemented at the student housing.

Since the project focuses on the production of energy, performance can be easily measured. Water levels have a gradient of 1.13 metres. A maximum of 54 m³ of water per second
runs through the power-plant. The modernisation of three turbines in 2013 resulted in an average increase in power production of about 130,000 kWh per year. In 2017, the powerplant produced about 2,320,000 kWh/a and reached an efficiency rate of 96%. To generate the same amount of power using fossil fuels, the environment would be polluted by 2,500 tonnes of carbon dioxide per year. 350 hectares of forest would not be enough to decompose this containment.

The “Upper Mills” neighbourhood is completely supplied by “green power”. The share in total power generation adds up to 19%. The remaining 81% of generated power comes from the public power supply. Refunds for this power follow State principles. Overall, the ecological footprint can be considered almost climate-neutral. The “Upper mills” project raises awareness and provides
an educational service by offering tours on technology, water
protection and renewable energy.

Why it works

✚ Europe’s first underground run-of-river hydro-power-plantin a historic setting.
✚ Water and energy consumption were reduced by about
15 to 25 %. This is remarka-ble without the direct financial advantages or incentives. Instead, students pay lump
sums for utilities in the residence.
✚ The hydro-power-plant produced about 2.320.000 kWh/a
power – completely emission-free