Content

Solar Systems 2021

Methodology

The two maps feature multiple layers that differ thematically and spatially. This is both for data protection considerations a well as academic reasons. The layers are self-contained; combining several of the two-dimensional layers will not generate any additional information.

More specifically, the maps consist of the following specialised layers:

Map 08.09.1 Photovoltaics contains 9 layers:

  • PV system locations for small systems up to 30 kW (not true to location) and above 30 kW
  • Installed capacity of the PV systems presented separately per borough and postal code area
  • PV electricity feed-in presented separately per borough and postal code area
  • Theoretical PV potential per building
  • Relative coverage rate presented separately per borough and postal code area (ratio of the output that can be achieved theoretically to the already installed capacity).

Map 08.09.2 Solar thermal energy contains 4 layers:

  • ST system locations (data protection reasons allowed only for a limited range of scales to be used for presentation)
  • Total number of ST systems presented separately per borough and postal code area
  • Theoretical ST potential per building.

Map 08.09.1 Photovoltaics

With the amendment of the Renewable Energy Sources Act (EEG) in August 2014, the responsibility for publishing PV system data was transferred to the Bundesnetzagentur (Federal Network Agency) as a centralised institution with uniform standards across Germany. This is a distinctive feature of the current methodology. Previously, the responsibility for publishing PV system data was with the network operators, who would usually publish information on the address and generator output of all systems on their own websites. For data protection reasons, the Federal Network Agency only publishes the postal code for systems below 30 kWp; the exact address including street name and house number is only published for an output of 30 kWp or more.

Map layer “PV system locations for small systems up to 30 kW (not true to location) and above 30 kW”:

The data set only includes systems that are subsidised according to the EEG. Systems that do not feed into the grid and use the electricity exclusively for self-supply are not included in the presentation. This applies for example to off-grid systems and stand-alone power systems, such as PV modules on parking meters, park lighting systems and in allotment gardens.

The location of systems above 30 kW was determined based on the address details provided by the system data reported. It cannot be ruled out that these may deviate slightly from the actual system location in individual cases, as it was not always possible to match the system to its roof. Due to data protection regulations, systems of up to 30 kW are not displayed at their exact location but are presented together in the centre of a specific postal code area.

The PV system data for the period from 2017 to January 2021 is based on preliminary reports from the core energy market data register and the EEG installation register of the Federal Network Agency. As data on existing systems is still being added, the figures are still incomplete. This data will be added successively as part of the updating process, however, i.e. the figures will be completed gradually.

Map layers “Installed capacity of the PV systems per borough and postal code area”:

The data set only includes systems that are subsidised according to the EEG. The Anlagenregisterverordnung (Installation Register Ordinance) (in force until August 2017) summarised all master and billing data for PV systems previously reported by the transmission system operators. This data is address-specific and was summed up per borough and postal code areas.

Map layers “PV electricity feed-in per borough and postal code area”:

The electricity feed-in data presented includes the billed quantities determined by the Stromnetz Berlin GmbH, aggregated by borough and postal code area. For the electricity feed-in, the measured data and the data billed in accordance with the valid, defined market processes is available. The available annual values are not to be regarded as final; changes may still have occurred in individual cases, for example due to billing corrections.
Considerable annual fluctuations in electricity feed-ins may occur in individual areas. Specific reasons may include weather fluctuations, system extensions or operational failures. Based on the available data, however, it is not possible to identify the exact underlying reasons.

Map layer “Theoretical PV potential per building”:

Part of developing the Solar Atlas Berlin was to determine the PV potential. This involved using available data, such as orthophotos and ALK building floor plans, as well as transparent calculations as a basis (cf. BLC 2011 for more detailed information). The map does not differentiate between rooftops already equipped with PV systems and those without. In addition, building developments, i.e. new constructions, modifications or demolitions that occurred after the data collection was complete (end of 2013) are not considered here.

As a result of the analysis, the rooftops are sorted into three suitability classes: highly suitable (>95 % of the highest possible annual irradiation in Berlin), suitable (90-95 %) and moderately suitable (80-90 %). Click here for an in-depth description of the methodology (only in German). The fourth class presents all rooftops that were classified as “unsuitable”.

Analysing this potential enabled Berlin to provide initial estimates for the future use and production of solar electricity (e.g. for building owners) in the city. However, this information does not replace the expert assessment of the individual object that is still required, for example in relation to the statics of the roof, before a solar system can be planned in detail and eventually constructed. The technical suitability is therefore not guaranteed and needs to be determined for each individual case.

Map layers “Relative coverage rate of the actual output compared to the theoretical PV output that can be achieved by borough and postal code area”:

The theoretical PV potential for highly suitable rooftops was calculated as part of analysing the PV potential for the Solar Atlas Berlin (cf. previous section), which resulted in the present data. The latter was also based on information on existing stock supplied by the Installation Register Ordinance (in force until August 2017, cf. sections above), which provided the actually measured feed-ins.

At first glance, the relative coverage rates between the potential and existing stock calculated for the boroughs and postal code areas appear to be relatively low. This is, however, due to the difference between the theoretically calculated potential and the potential that is technically feasible. These would need to be confirmed individually by further investigations and calculations to facilitate reliable assessments.

Map 08.09.2 Solar thermal energy

At this point, it is helpful to remember that not every installed system could be recorded in the solar cadastre in its final version as of December 31, 2015. Four years and 600 new systems separate the location data of the cadastre and the updated and aggregated version from late 2019.

Map layer “ST system locations”:

Due to data protection regulations, the presentation of system locations (as of December 31, 2015) is only permissible for certain scale ranges. The solar thermal systems are therefore presented only at a scale of 1:15,000 and larger.

Map layers “Total number of ST systems presented separately per borough and postal code area”:

The data presented also includes updates for the years between 2016 and 2019, i.e. additions based on information provided by the Federal Office of Economic Affairs and Export Control (BAFA). The data is only available at postal code level, which forms the most detailed level here. It was therefore possible to adjust the total number summed up at postal code and borough level. The location of individual systems, however, could not be identified.

Map layer “Theoretical ST potential at building level”:

Part of developing the Solar Atlas Berlin was to determine the PV potential. This involved using available data, such as orthophotos and ALK building floor plans, as well as transparent calculations as a basis (cf. BLC 2011 for more detailed information).

Rooftops with a highest possible annual irradiation of more than 80 % and a surface area of at least 5 m² for pitched roofs and 15 m² for flat roofs were considered suitable for solar thermal systems. A further classification was not made due to the strongly use-dependent suitability.

Analysing this potential enabled Berlin to provide initial estimates for the future use and production of solar heat (e.g. for building owners) in the city. However, this information does not replace the expert assessment of the individual object that is still required, for example in relation to the statics of the roof or required heat, before a solar system can be planned in detail and eventually constructed. The technical suitability is therefore not guaranteed and needs to be determined for each individual case.