Detailed description and data of the solar power system
During the planning of the settlement, it was already taken into account that a photovoltaic system was to be implemented on some of the roofs. For this reason, some of the roofs were already designed during construction so that the later attachment of the substructure for the modules should be possible without any problems. The following areas are available on the three roofs planned for the photovoltaic system: Roof A: approx. 535 m² roof area - Roof B: approx. 410 m² roof area -Roof C: approx. 410 m² roof area.
All roofs are provided with a sheet metal covering, which is responsible for the roof waterproofing. The substructure is formed by reinforced wooden beams, which can take the additional load of the photovoltaic system. The roofs are almost optimally aligned to the south and have an inclination of approx. 20°. All roofs are almost completely covered with solar modules. This results in a total generator area of 1,172 m². In relation to the available roof area, this results in a specific area used for the photovoltaic system of approx. 86 %.A total of 1,250 modules from the manufacturer Kyocera were used on the three roofs. These are polycrystalline modules with a performance guarantee of 25 years from the manufacturer. The total output of the photovoltaic system is 145 kWp. The entire system is divided into several module strings, each of which is routed separately to the generator connection box. 25 modules per module string are electrically connected in series. A total of 26 inverters were used to convert the direct current of the modules into grid-compliant alternating current. The alternating current converted by these is fed completely into the public power grid of Bewag. The solar plant was realized by the Berlin Phönix Solar Initiative.
Energy yield and pollutant reduction
During the planning of the system, a simulation of the system was carried out based on the data of the components used (modules/inverters). This took into account the compass direction and roof pitch, as well as the interconnection of the modules to form individual strings. For all three roofs, the specific yield of the system was over 800 kWh per kWp of installed nominal power. In total, the photovoltaic system will feed about 100,000 kWh of solar power into the Bewag grid annually, thus contributing to the reduction of pollutants:
- Carbon dioxide (CO2): 90,000 kg per year
- Sulphur dioxide (SO2): 75 kg per year
- Nitrogen oxides (NOX): 220 kg per year
Promotion and economic efficiency
For the photovoltaic system of the Heinrich-Böll-Siedlung, a subsidy was applied for and approved within the framework of the "Solar Power Exchange" of Bewag. This resulted in an initial subsidy for the system of approximately 3,000 to 3,250 euros per kWp of installed capacity. With a plant output of 145 kW, this results in a subsidy of just under € 0.5 million. In addition, Bewag will pay approx. € 0.34 for each kilowatt hour of solar power generated and fed into the public grid. With a probable total annual feed-in of more than 100,000 kWh of solar power, this results in an annual payment of approximately €35,000 for the developer. Due to the initial subsidy and the remuneration for the solar power fed into the grid, the system has almost paid for itself economically by the time the increased feed-in tariff expires. Not taken into account here are possible maintenance and repair costs, which are to be borne by the builder. Recently, the builder has been receiving the increased feed-in tariff from the 100,000 Roofs Programme of 0.5 euros/kWh. This should make the solar system economical to operate
Overall, a well-integrated photovoltaic system in terms of design, which can be recommended as a model for other housing associations and homeowners.
More info:
http://sdg21.eu/db/heinrich-boell-siedlung
