Planning a PV system: an overview of the components

A photovoltaic system consists of four components that must work together: solar panels generate direct current, the inverter converts this into alternating current for the home and the grid, a storage unit stores the surplus for the evening, and the mounting structure holds everything in place on the roof. This page guides you through the planning process in this order. If you do not wish to coordinate the components yourself, you will find the ready-made combination under ‘PV system’ as a complete set.

Most modules in the range measure around 1.76 × 1.13 m, i.e. approximately 2 m² per module. Per kWp, a system therefore requires a good 4 m² of pure module area; a 10 kWp system would thus require around 43 m², excluding any edge clearances. The practical size of the system also depends on how much electricity is consumed in the house and at what time of day.

The module determines power output and space requirements. The range includes modules from several manufacturers, including JA Solar, Trina, Aiko, Solitek and TCL, mostly with outputs ranging from 290 to 505 W, almost all featuring a glass-on-glass design, some of which are bifacial or ‘Full Black’. Dimensions and weight are specified for each module. The overview: solar panels.

If you intend to include a storage system from the outset, a hybrid inverter is the obvious choice: it combines modules, battery and domestic mains in a single unit. Information on how to wire modules and inverters can be found under ‘Solar cables and MC4 connectors’. Without a storage system, a grid-tied inverter is sufficient; this consumes the electricity directly in the home and provides the surplus for grid feed-in. The range includes hybrid units from 0.8 to 29.9 kW and grid-tied units up to 125 kW, available in single-phase and three-phase versions; the single-phase units are more suitable for smaller systems, and a specialist contractor will determine the correct specification. All units: inverters.

If a lot of electricity is used in the evening and at night, a storage system increases self-consumption; during the day, an electric car can also absorb the surplus – see ‘Wallbox with PV surplus charging’. The battery modules have a capacity of 2.56 to 5.12 kWh per module and can be stacked; ready-made sets are available with capacities ranging from 5 to 50 kWh. It is important that the storage system and inverter are compatible: under ‘Storage systems for inverters’, you’ll find the modules including the BMS (Battery Management System) for each manufacturer; all systems are listed under ‘Battery storage’.

Pitched roof, standing-seam roof, trapezoidal sheet metal or flat roof: the substructure must be suitable for the roof and the module size. For this purpose, there are roof hooks, rails and clamps – most of them from K2 Systems – and, for flat roofs, east-west kits for 2 to 12 solar panels. Which K2 parts are suitable for which roof is explained under ‘K2 substructure: Which parts fit which roof?’. Which mounting system is suitable for which roof and who checks the structural integrity is explained under ‘Mounting systems for solar panels’.

A complete set takes care of the coordination of the components. The complete PV sets with storage range from 6.8 to 30.2 kWp, featuring glass-on-glass modules from JA Solar or Trina, a hybrid inverter (predominantly three-phase) and 5 to 15.36 kWh of storage. The PV complete sets without storage have a capacity of 9.4 to 16.92 kWp; information on how to add storage at a later date can be found under ‘Retrofitting PV storage’. Sets with around 10 kWp are grouped together under ‘10 kWp PV system with storage’.

As a complete set including storage, a PV system in the range costs about 350 to 600 €/kWp per kWp; around half of the sets are priced between 430 and 600 € per kWp (as at October 2026). A system with around 10 kWp and storage therefore comes to about 4,300 to 5,700 €. Larger systems are usually cheaper per kWp than smaller ones.

The price is determined primarily by the module output, the storage capacity and the inverter. Sub-structure, installation, electrical connection and registration are added to this. The price ranges are the shop prices excluding VAT: for PV systems, no VAT is payable under the conditions set out in Section 12(3) of the German Value Added Tax Act (UStG). Please indicate during the ordering process whether these conditions apply. You can find the relevant information under ‘VAT on products related to photovoltaics’. The prices by size are listed under ‘PV system with storage’, whilst the sets with around 10 kWp are listed under ‘10 kWp PV system with storage’.

Where a full roof is not available, a balcony power plant is a good place to start. The grid operator and the Federal Network Agency provide information on power limits and registration.