Photovoltaic Systems/Packages


Photovoltaics in Germany is a success story that, in the past, was due in no small part to the Renewable Energies Act (Erneuerbare-Energien-Gesetz (EEG for short)). However, as a consequence of the reduction in the feed-in revenue to currently 12.31 euro cents per kilowatt-hour (kWh) of solar electricity and the present mains electricity price of around 28 euro cents per kWh, the order of the day is no longer feeding in, but: self-consumption optimisation with photovoltaic systems (PV systems).

The following figures show that this development has in no way led to a decline in photovoltaics in Germany: In 2015 the production of photovoltaic systems increased by around 4.8% in comparison with the previous year to 37 TWh. Photovoltaics accounted for about 6% of the total electricity mix (gross electricity generation). Further growth was recorded in 2016. PV accounted for just under 6.5% of the German electricity mix in the first half year.

Germany’s obligation to increase the percentage of the gross electricity consumption attributable to renewable energies to at least 80% by 2050 is the main force behind the increasing number of installed photovoltaic systems.

On this page you can learn what you need to bear in mind if you wish to become part of the success story with your own photovoltaic system in Germany. You’re given all the information, from the planning of your photovoltaic system to its installation. You’re welcome to contact us, should you have any questions.

The complete packages from SOLARWATT

SOLARWATT offers a range of different photovoltaic systems. Depending on whether you want to optimise your electricity consumption at low cost, use your free solar electricity for your hot water or simply achieve the maximum self-consumption, with the complete packages you have a choice of different systems in various performance classes.

How does a photovoltaic system work?

Solar systems generate electricity from sunlight, or rather solar energy. The sun’s rays fall on the solar cells in the modules, creating DC electricity. Since alternating current flows both in the household network and in the national grid, however, an inverter subsequently converts the direct current to alternating current.

The solar energy generated in the solar power system can now either be used directly by household appliances and other consumers, stored in a battery storage system for later use or fed into the national grid.

1. Checking your property and finance

The following points should be clarified in the early phase of the planning: Is your property suitable for the mounting of solar modules and which form of financing or subsidy comes into question for you? In Germany, for example, the Kreditanstalt für Wiederaufbau (KfW Bank) has various solar subsidy schemes on offer.

2. On-site appointment with a specialist partner

Our competent and reliable specialist partner obtains an initial impression of your property and also checks the structural requirements. Our specialist partner will be glad to advise you comprehensively and answer your questions.

3. Obtaining a quotation

A short while after the preliminary appointment you will receive your personal quotation.

4. Checking the quotation

Check the quotation with regard to the completeness and correctness of the data.

5. Placing the order and commissioning

As soon as you have placed the order with our specialist partner, he will agree an installation date with you. Following the completion and comprehensive testing, including the preparation of a test report, the system is handed over to you. On the day of the handover you will also receive comprehensive instruction on the system and its operation so that you can put it into operation afterwards.

6. Maintenance

A solar system must be maintained at regular intervals.

Our tip: Take out a maintenance contract with our local specialist partner. You don’t need to ensure that the maintenance intervals are complied with and you always have a contact person.

Generating electricity yourself – requirements and preconditions

Certain structural preconditions need to be met for the installation of a photovoltaic system. Things to be considered in advance are, for example, the orientation and pitch of the roof as well as the size and condition of the roof surface. In the case of a roof with many windows or dormers, the usable area for the PV system and the solar energy yield are reduced in comparison with a roof with no such special features. Further important factors are the roof statics and possible shading.


Roof pitch

On flat roofs the solar modules are uprighted with the aid of metal frames, while on pitched roofs they are mounted parallel to the roof surface. In case of deviations it may be necessary to mount more modules for the same output. The rule of thumb is: a roof pitch of between 20° and 30° is ideal for the generation of solar electricity.

Strength of the solar irradiation

The solar irradiation is sufficiently high in all regions of Germany to be able to operate a photovoltaic system profitably. Learn more


Shade can lead to a reduced output of a photovoltaic system. It is therefore advisable to observe the roof surface before the installation with regard to possible shading, including in the future due to tree growth or the neighbour’s building plans.

Roof orientation

A roof facing south is ideal, but photovoltaic systems can also be mounted roof surfaces with other orientations. In that case, however, a larger number of modules may be required to achieve the same output.

Domestic electrical installation

For the connection to the national grid, solar cables need to be laid from the roof to the basement or the utility room.

Legal aspects related to photovoltaic systems

Legal questions always have to be observed when installing a PV system. These include the following topics: The necessity of planning permission, how the income from the system is to be taxed and guarantees/warranties for the components.

Planning permission is not normally required for a photovoltaic system on the roof of a house, since this is considered a structural measure. Special rules apply to installations on listed buildings. Further exceptions, depending on the federal state, are systems that project from the building or regulations arising from the local development plans. You can get information about the respective rules from the applicable building regulations.

Particular caution must be exercised in relation to the natural surroundings of a planned system. The building regulations specify the extent to which the surroundings may be adapted to suit the requirements of a photovoltaic system – for example, whether a tree may be felled in order to prevent shading.

Observe applicable building regulations

The applicable building regulations must be checked to ascertain whether and what changes to the surroundings may be made in order to improve the output of the PV system.

Feed-in revenue and solar loans

A further legally relevant topic is the financing of a solar system. In Germany, this area covers the feed-in revenue fixed by the legislator in the EEG (Renewable Energies Act). This is a fixed sum that system operators receive from the grid operator for the feeding-in of the solar electricity from their system. Due to the low remuneration this model is no longer relevant, particularly in the case of new installations.

The so-called solar loans offer a further finance option. Various banks, including the Kreditanstalt für Wiederaufbau (KfW) in Germany, offer consumers loans for the acquisition and installation of a photovoltaic system. You can find further information of this topic here.

Before you commence with the installation of a photovoltaic system or place an order with a specialist to do so, please inform yourself about the applicable building regulations and any planning permission that may be necessary.


High-value photovoltaic modules secure good yields

The main constituent parts of a PV system are the photovoltaic modules. The better the technology, the higher the yields and the more reliable they are in the long term – as is the case with the glass-glass modules from SOLARWATT.

Optimise output with the right inverter

Since the direct current generated by the solar system normally cannot be used, an inverter converts it into alternating current. You have a choice of many inverters – we’ll be glad to help you.

Firm hold of the sub-construction is decisive

The sub-constructions of PV systems serve to support the modules on roofs. On account of the loads due to weather influences and the weight of the modules, sub-constructions must be of particularly high value.

Cables – the important connections between components

The cables of a solar system transmit the current from the modules to the inverter. To ensure trouble-free operation, it is best to lay top quality photovoltaic cables that are resistant to external influences.

Installation of a solar system

The installation of a photovoltaic system should be carried out only by specialist companies. Our competent specialist partners in your area will be glad to help you.

The photovoltaic systems are mounted with a sub-construction on the existing roof covering and are thus particularly suitable for retrofitting PV to existing properties. The modules are mounted a small distance above the roofing tiles – it is essential to ensure sufficient air circulation behind the modules. Particular care must be taken during the installation not to damage the roofing tiles or the insulation.

In the case of tiled roofs, which are commonest in Germany, hooks are screwed into the rafters. The installer then mounts rails on the hooks to which the solar modules are fastened. Depending on the type of module, they can be bolted, hooked in or fastened with clamps. An alternative to conventional rooftop solar systems are roof-integrated systems.

After the installation is before the maintenance

Despite the low maintenance requirement of PV systems, this topic should not be neglected, because a photovoltaic system consists of various components that on the one hand are exposed to varying degrees to external influences and on the other hand have service lives of different lengths. The maintenance requirement for solar modules is particularly low. In particular the glass-glass modules from SOLARWATT are very durable and extremely robust. By comparison, irregularities are more likely to occur with cabling and inverters, which can be quickly rectified through regular maintenance. Further information on the subject of maintenance.

Self-consumption optimisation with photovoltaic systems

What does self-consumption optimisation with photovoltaic systems mean? The central concept is to consume as much of the self-generated solar electricity as possible in one’s own household in order to reduce the quantity of mains electricity required. There is a very simple calculation behind this: The more free solar electricity consumed by the system operator, the lower the requirement for mains electricity.

This means: If you feed in solar electricity for a remuneration of 12.31 euro cents per kWh and purchase in its place mains electricity for around 28 euro cents per kWh, you still pay almost 16 euro cents for your solar electricity despite your photovoltaic system, even though the actual solar electricity costs nothing.

How can you achieve the highest possible self-consumption? Combine your solar system with a battery storage system, as in the SOLARWATT Store complete package. This stores excess electricity until you really need it. Since the electricity consumption is highest in the evening and at the weekend, you can use the stored electricity during this period instead of the expensive mains electricity.

A high self-consumption hence results on the one hand in a lower electricity bill and on the other in more independence, because the less mains electricity you require, the more independent you become from the energy supplier.

Independent thanks to high self-consumption

Photovoltaic systems and battery storage systems – added value or wishful thinking?

The connection of photovoltaic and battery storage system is on everyone’s lips at the moment. But is the installation of a battery storage system really worthwhile? In a word: Yes.

Since the Bundesnetzagentur (Federal Grid Agency) radically reduced the remuneration paid to system operators for electricity fed into the national grid (feed-in revenue), it is more worthwhile consuming the free solar electricity oneself. A

battery storage system, sometimes also referred to as a solar battery storage system, ensures that the solar electricity is available precisely when it is needed. This means that stored solar electricity is available when you need it – day or night. As a result, system operators require less of the expensive mains electricity; the energy costs are lowered and independence is increased.


The process, from the search for information to the installation and commissioning of a photovoltaic system, is very complex and requires extensive planning. We support and advise you through the individual steps. Our reliable specialist partners also help with the precise planning and take care of the installation of the SOLARWATT complete package for you.

Information & Service


Particularly good looking and in the familiar SOLARWATT quality, we present to you our Style glass-glass modules. They are an eye-catcher on any roof and deliver the highest yields.

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