23.06. – 03.07. | EAERE Conference 2020
25. June 2020
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30. June 2020

Solarcity: Study on the potential for photovoltaics in the old town of Spandau

In the project "Solar Study Old Town Spandau", RLI determined the potential for photovoltaics on the roof surfaces of the old town of Spandau.

The city of Berlin has set itself the goal of becoming climate-neutral by 2050. To achieve this, renewable energy in the city must be expanded considerably. In densely built-up urban areas, solar energy is usually the best option for generating electricity from renewable sources – the many roof surfaces are ideal locations for photovoltaic systems. Based on a study by the Fraunhofer Institute for Solar Energy System (ISE), which determined Berlin's solar power potential at 25 percent, a photovoltaic capacity of 4,400 MWp would have to be installed in Berlin by the target year 2050 to be able to generate around 4,000 GWh of solar power each year.

These goals are implemented in the Masterplan Solarcity Berlin, which was ratified by the Berlin Senate in March 2020. Almost all departments of the Berlin administration are contributing to this plan.

Analysis of potential in several steps

The Berlin districts independently check where suitable roof areas for photovoltaics are located and how homeowners can be supported in making use of them. In case of the old town of Spandau, the RLI Research Unit Transformation of Energy Systems took on the task of determining the demand and the existing potential. For this purpose, existing photovoltaic systems in the old town were identified, their current output was determined, and the roof surfaces that were potentially suitable were evaluated. In addition, a detailed investigation was carried out for four private and four public buildings to determine how solar systems can be installed and operated.

What do suitable roofs for photovoltaic systems look like?

Criteria used to assess the suitability of a roof surface for generating electricity with photovoltaics include its size, any obstacles such as chimneys or skylights, the direction in which the roof is facing, the general condition and load-bearing capacity of the roof, and any restrictions imposed by historic preservation rules.

Historic preservation is not an exclusion criterion

The old town of Spandau has the special feature of a large stock of historical buildings, some of which are listed as cultural heritage and therefore fall under historic preservation rules. This also applies to two of the public buildings, which are examined in detail. Consideration of the protection of historical monuments is an explicit part of the study in order to gain insights into how such special structural conditions and climate protection can be reconciled.

Project duration: September 2019 - July 2020

RLI is preparing a study on the potential of photovoltaics for the old town of Spandau based on the following steps:

  • Determination of the power requirements:
    • Preparation of current load profiles (15-minute values) for each building block in the old town of Spandau
  • Recording of the inventory of photovoltaic systems (data sources: Core energy market data register and aerial photographs)
    • Calculation of typical production time series for each plant, each block, and the entire area
  • Determination of suitable roof areas as well as the expected generation capacity there (data sources: Solar Atlas Berlin and Spandau District Office)
  • Detailed considerations for the construction and operation of PV systems on four private and four public buildings


Birgit Schachler

Project manager

Mascha Richter

Unit Head

Sabine Haas


Sarah Berendes