Photovoltaics FAQ - Answers to your questions

For commercial photovoltaic systems from 135 kWp, the complete price varies between €800 and €1,200 per kWp, depending on the size and type of system. As a rule of thumb, the larger the solar system, the lower the costs per kWp.

The more solar power a company can use directly from its own PV system, the more economical it is. If the so-called self-consumption rate is high or the electricity is primarily used by the company itself, a solar system pays for itself from day one.

In addition to the EEG subsidy, there are various other subsidy programs in Germany that vary from state to state or from municipality to municipality. The size and type of the planned system also play a role. Even if an investment in a PV system is extremely profitable even without any subsidies, all subsidy options should be checked and individually evaluated in advance. CUBE CONCEPTS advises and supports you in all matters.

Commercial photovoltaics on commercial and industrial roofs do not require a traditional building permit in Germany. However, a technical building permit must be obtained, a grid compatibility test must be applied for from the grid operator and a feed-in commitment must be made. Solar parks and solar carports, on the other hand, always require a conventional and technical building permit. The experts at CUBE CONCEPTS take care of all the bureaucratic work in advance and clarify all questions with the grid operators, the municipality, the district and the regional planning level

When installing a PV system on the roofs of existing buildings, CUBE CONCEPTS recommends a structural analysis by our independent structural engineering partners. Even if the solar systems from CUBE CONCEPTS do not penetrate the roof, wind and snow loads acting on the modules can have an influence. In general, the DIN 1055 and DIN EN 1991 standards are observed and factors such as module weight, module inclination, snow loads according to the snow load zone map, wind according to building height and location as well as other aspects are taken into account. A roof load reserve of between 10 and 24 kg/m² is generally recommended, depending on the nature of the roof.

Thanks to CUBE CONCEPTS' extensive network of solar installers, delivery can be made promptly and construction can begin no later than 8-12 weeks after grid approval.

Operators of PV systems up to 1,000 kWp have received a higher EEG feed-in tariff since January 1, 2023 if their system was commissioned after the cut-off date. These guaranteed feed-in tariffs vary and depend on the system size and feed-in volume. Operators of commercial photovoltaic systems with more than 100 kWp are obliged to commission a direct marketer to market the electricity generated and fed into the grid and therefore do not receive a statutory feed-in tariff, but a combination of the market value of the electricity and the market premium. This amount is currently generally somewhat higher, as the contracts are usually calculated on a long-term basis and short-term fluctuations in the electricity price are compensated for somewhat by means of average values.

The law passed on 20.12.2022 on the introduction of an electricity price brake (Electricity Price Brake Act - StromPBG) stipulates, among other things, that operators of commercial photovoltaic systems have had to pay their surplus revenues since December 1, 2022. These are calculated on a quarterly basis using various ratios, such as monthly market value or system size. The revenue levied from the so-called random profits is to benefit end consumers.

More on the electricity price brake

CUBE CONCEPTS calculates the electricity price openly and transparently. Even if customers do not enter into an off-take obligation with CUBE Contracting, they can benefit from long-term electricity price security thanks to the long contract terms of 15, 20 or 25 years. CUBE CONCEPTS calculates the total investment costs, including the margin, and sets the electricity price for customers over the long term.  

Commercial photovoltaic systems are extremely low-maintenance and durable. They clean and snow and over a period of 20 years, experience has shown that the maintenance costs amount to a maximum of 1.5 % of the original investment. With CUBE Contracting, there are no additional costs for the client anyway. In the case of CUBE purchase, they should build up a reserve for repairs or the replacement of an inverter and insure the system. CUBE CONCEPTS offers its clients a proven and comprehensive insurance package for this purpose.

With efficient solar modules and increased electricity costs, a commercial photovoltaic system will pay for itself in a maximum of 6-8 years.

CUBE CONCEPTS calculates each photovoltaic system individually and selects the most suitable solar modules for a PV project. The experts plan monocrystalline modules with the highest current efficiency and a long service life. Currently, for example, the guaranteed remaining output after 20 years is 90%. As a rule, modules with a size of approx. 100×180 cm are installed on roof surfaces and they each have a maximum rated output of over 400 W. However, the choice of modules naturally depends on the type of system planned. For photovoltaics on roof surfaces, CUBE CONCEPTS takes into account the respective roof load reserves and implements the PV system according to the existing load-bearing capacity.

In contrast to small private photovoltaic systems, various fire protection requirements must be taken into account for commercial PV systems. CUBE CONCEPTS meets these requirements right from the planning and implementation stages. The application rule 2018-12 of the VDE-AR-E 2100-712 is decisive here.

In particular, DIN 18234, DIN 18008 and DIN 14449 should be mentioned when selecting modules. For the installation of low-voltage systems, DIN VDE 0100-200, for snow and wind loads 5400 Pa, DIN EN 61215, VDE 0126-31 and DIN 1055-4/-5 must be observed. The inverters are installed in accordance with VDE 0100-712, DIN EN 62109, VDE 0126-14-2 and VDE V 0126-1-1.

If the PV system is to have a battery storage system, CUBE CONCEPTS observes these specifications: DIN EN 50272-1, DIN EN 50272-2, VDE 0510-1, VDE 0510-2, VDE-AR-E 2510-50, VDE 0100-443, VDE-AR-E 2510-2, VDE 0100-443, DIN VDE 0100-712, VDE 0100-600 and VDE-AR-E 2510-2.

VdS 2025, DIN VDE 0100-520, DIN VDE 0100-712, VDE 0283-618, VDE 0100-712, VDE 0660-600, VDE 0606-24, DIN EN 50618, DIN EN 61439 and DIN EN 60670-24 apply to all cable and wiring systems and VDE-AR-E 2100-712 and VDE 0100-712 apply to the DC disconnecting device. During commissioning, CUBE CONCEPTS complies with DIN EN 62446-1, VDE 0100-600 and VDE 0126-23-1.

Further fire protection regulations are regulated in DIN VDE 0100-712, VDE 0100-712:2016-10 or DIN EN 62446-1, DIN 4102-7, DIN EN ISO 13943 and VDE 0126-23-1:2019-04, among others. Of course, we also observe lightning protection in accordance with IEC 62305-2, 62305-3, VDE 0185-305-3 and NFPA 780.

Here an overview of all specifications. 

CUBE CONCEPTS provides its clients with a comprehensive and proven PV insurance package including all property insurance against hail damage, overvoltage or business interruption insurance with disassembly and reassembly in the event of a roof renovation. CUBE CONCEPTS complies with VdS 2033, VdS 2025 and VdS 2234.