Solar Systems 2021


Renewable energies, i.e. primarily wind power, geothermal energy, biomass and solar energy, are inexhaustible sources of energy. They represent an important alternative or addition to fossil fuels in Berlin’s energy supply. The expansion of solar energy use is emphasised as a particularly important building block in Berlin’s climate protection strategy, since, with over 560,000 buildings in Berlin, there are rooftops and house façades aplenty, unlike suitable wind power sites. By 2050, the Berlin Senate aims to have achieved a climate-neutral energy supply of the city. The goal of increasing the generation and use of renewable energies on public buildings is established in Article 16 of the Berlin Energy Turnaround Act of March 22, 2016 (EWG Bln 2016). In addition, the expansion of renewable energies, in particular tapping into the potential of solar energy, was adopted by the Berlin Senate in the Berlin Energy and Climate Protection Programme 2030 (BEK 2030) (Abgeordnetenhaus Berlin 2016).

According to the BEK 2030, the “Masterplan Solarcity” (solar city master plan) forms an important stepping stone for overcoming existing obstacles and building on the currently rather limited development of solar energy. In September 2019, after an in-depth and hands-on process, the “Expertenempfehlung zum Masterplan Solarcity Berlin” (expert recommendations for the Berlin solar city master plan) was presented to the lead Senate Department for Economics, Energy and Public Enterprises. Combined with an extensive catalogue of measures, it forms the basis for the future expansion of solar energy in Berlin. The study confirms that Berlin has a potential solar power share of 25 %, provided that better framework conditions are put in place at federal level, creative approaches are taken on site and a variety of instruments is applied (Masterplan Solarcity, only in German).

Based on this, the Senate passed a comprehensive action plan to accelerate the development of solar energy in Berlin on 10 March 2020 (Senate Chancellery 2020). The first monitoring report on the “Masterplan Solarcity” has been available since January 2021 (SenWEB 2021).

The set of measures stipulated in the master plan is accompanied by the proposal of a Berlin solar law. Solar panels shall be mandatory from January 1, 2023. The installation and operation of photovoltaic systems will then be mandatory for new and existing buildings under certain conditions (SenK 2021).

So far, solar power has accounted for less than 0.5 % of the total generated power (Berliner Morgenpost 2019). To start tapping more into the potential of solar energy, both in the private and the public sector, the SolarZentrum (solar centre) Berlin was opened in May 2019. It is a component of the “Masterplan Solarcity”, which works as an independent advisory centre on the topic of solar energy (SolarZentrum Berlin, only in German). The centre is operated by the German Section of the International Solar Energy Society (DGS) and the Berlin Brandenburg regional association, supported by the Senate Department for Economics, Energy and Public Enterprises.

Previously, the use of energy-relevant data, such as solar data, and how it was presented on the map, was handled inconsistently using a variety of channels. In July 2018, the Energietlas Berlin (Energy Atlas, only in German) was created as a portal specialised in supporting the energy turnaround. For this purpose, it presents the most important data in a user-friendly and visually comprehensive way, which is updated regularly.

The Environmental Atlas contents regarding

  • Photovoltaics (PV), i.e. the direct conversion of solar energy into electrical energy and
  • Solar-thermal energy (ST), i.e. the generation of heat from insolation

presented here refer to data published in the Energy Atlas on photovoltaic systems (as of January 1, 2021) and solar thermal systems (as of December 31, 2015 and as of 2017 for aggregated BAFA data).

The plan is to further improve the frequency and quality of the data on solar systems as part of updating Berlin’s Energy Atlas.

Map 08.09.1 Photovoltaics

There are far fewer photovoltaic than solar thermal systems in Berlin. As of January 1, 2021, some 10,2006 systems were in place, with a total installed capacity of around 155 MW. The electricity that these generate per annum can only be estimated and is expected to amount to approx. 139 million kWh/a (minus 5 % for the generator output and an average electricity yield of 900 kWh/a per kW). Theoretically, this output could cover the supply of about 34,900 households with an assumed average electricity consumption of 4,000 kWh/a each.

The previous method of data recording used in the solar cadastre was discontinued with the introduction of the Energy Atlas. The method switched to a combination of multiple sources (cf. Statistical Base) and ways of presenting analysis results. Figure 1 presents the range of development numbers by borough (Fig. 1a). Here, urban areas largely characterised by single and two-family homes account for the largest shares. In line with this, the lowest capacity class of up to 30 kW (Fig. 1b), the preferred choice for smaller roofs, predominates with about 9,400 of the 10,200 systems. The amendment of the Renewable Energy Sources Act (EEG 2014) of August 1, 2014 affected these development figures negatively. The number of systems installed prior to the amendment had been considerably higher. About 88 % of the capacity recorded for the year had been installed by August 1. The negative change in framework conditions associated with the amendment, affecting particularly small and medium-sized systems, can thus be assumed to have caused the slump in PV expansion in Berlin also in the following year of 2015. With the amendment, the EEG surcharge was also introduced for using your own electricity. The contracting model used by housing cooperatives in Berlin, for example, which supplied residents with their own PV electricity while the PV system remained the property of the investor, became much less attractive following this change. According to the Bundesnetzagentur (Federal Network Agency 2020), this trend continued and was observed nationwide in the two years following the EEG amendment coming into force in August 2014.

In terms of area-related expansion of photovoltaic capacity, the State of Berlin, with 11.6 kWp/km², still ranked first among the federal states in 2017. In 2018, however, the states of Brandenburg and Saxony-Anhalt with a larger territory saw a much greater expansion (Renewable Energies Agency, March 2021). The cadastre does not include off-grid systems, e.g. for self-supply and stand-alone power systems, such as PV modules on parking metres, park lighting systems and in allotment gardens. These are estimated to amount to an extra 2,500 systems.

Enlarge photo: Fig. 1a: Development by borough
Fig. 1a: Development by borough
Image: Umweltatlas Berlin
Enlarge photo: Fig. 1b: Development by capacity class
Fig. 1b: Development by capacity class
Image: Umweltatlas Berlin

Map 08.09.2 Solar Thermal Energy

The previous method of data recording used in the solar cadastre was discontinued with the introduction of the Energy Atlas. The method switched to a combination of multiple sources (cf. Statistical Base) and ways of presenting analysis results.

As of December 31, 2019, there were about 8,000 solar thermal systems in the State of Berlin with a combined installed collector surface of some 71,000 m². Averaged over the years, the collector surface amounted to around 11 m² per system. As compared to the years prior to 2013, the following years saw a sharp decline in the growth of new installations, a development that is highlighted in Figure 2. Overall, a declining trend has been observed since then. In Berlin, solar thermal systems are mainly used for hot water supply and to supplement space heating. In addition, some larger solar systems are used for heating drinking water and swimming pool water; they are further used for solar air systems and air conditioning systems. Similar to the distribution of PV systems, solar thermal systems are clearly concentrated in the outer areas of the city, which are characterised by more rural types of settlements (cf. Berlin representation at postal code level in Fig. 2; the darker shades represent more than 100 systems).

Enlarge photo: Fig. 2: Development of solar thermal systems in the State of Berlin in number of systems, by borough; Distribution per postal code area (as of December 31, 2020)
Fig. 2: Development of solar thermal systems in the State of Berlin in number of systems, by borough; Distribution per postal code area (as of December 31, 2020)
Image: Umweltatlas Berlin

Due to the incomplete recording of hot water supply systems, it can be assumed that the number of systems is actually higher. Flat plate collectors were chosen for the largest number of installations. Table 1 shows which collector types were installed in 2014 and 2015.

Tab. 1: Type and number of collectors of the solar thermal systems installed in 2014 and 2015 (as of October 31, 2015, final available update for these categories, source: IP SYSCON)
Collector type Number
Flat plate collector 80
Evacuated tube collector 52
Air collector 4
Not specified 9

Most solar thermal systems in Berlin were mounted on single-family homes. Table 2 displays the number of systems per building type according to the utilisation details presented in the Property Map ALK (SenStadtUm 2016), which was still in use at the time.

Tab. 2: Number of installed solar thermal systems based on the building type according to ALK (as of December 31, 2015, final available update for these categories, source: IP SYSCON)
Building type Number
Single-family home 4,895
Multi-family home 563
Other (non-residential) 66
Not specified 1,753

In Berlin, the number of new solar thermal systems has dropped dramatically since 2012 as compared to previous years and has continued to further decrease since then. The lowest increase in number and capacity of new installations since the year 2000 was recorded in 2015.

From 2016, the data for Berlin has been provided by the Federal Office for Economic Affairs and Export Control (BAFA), which is aggregated at a more general level and does not provide detailed information. Conclusions regarding collector types, building types or collector surfaces can therefore no longer be drawn.

Across Germany, the growth of new solar thermal collector surfaces has slowed since 2012, and by the end of 2019 it had dropped to a growth rate of around 500,000 to 600,000 m²/a (German Solar Association 2019). Generally, the curves for both growth (in area) and for the number of systems have flattened considerably in the last few years. The situation in Berlin therefore also reflects what is happening at a national level (cf. Fig. 2)