While photovoltaic systems on roofs and façades must be professionally commissioned by electricians, plug-in solar devices (so-called "balcony power plants") can simply be plugged into the outdoor socket yourself.

Plug-in solar devices usually consist of one or two solar modules and a micro-inverter, which converts the direct current generated into alternating current that is used directly in the household grid. This micro-inverter may currently have a maximum feed-in power of 800 watts - in relation to a final circuit, i.e. per residential unit.

The city of Bonn subsidizes the purchase of such plug-in solar devices, for example "balcony power plants" (subsidy module M13). In this way, people with lower incomes can also contribute to climate protection and at the same time reduce their electricity bills by 10 to 15 percent by drawing less electricity from the grid.

Plug-in solar devices are primarily intended for installation on balconies. Roofs, on the other hand, should be completely covered with modules in order to maximize the solar power yield. Plug-in solar devices on house and garage roofs will therefore no longer be subsidized for new applications from April 1, 2023. However, mini solar systems will continue to be subsidized if they are mounted or installed on balconies, facades, terraces or in gardens.

Suitable locations are those that are hardly shaded and face south, (south)-west or (south)-east. Photos of the installed and commissioned plug-in solar device as well as the registration in the  Federal Network Agency's market master data register (opens in a new tab) must be submitted for the funding application. Grant recipients must agree to the City of Bonn carrying out random on-site inspections when submitting their application.

For applications submitted since April 1, 2023, the grant is dependent on both the feed-in power of the micro inverter and the purchase price. Tenants (resident in Bonn) receive a subsidy of up to 480 euros, but no more than 60 percent of the invoice amount. Bonn ID card holders can receive a grant of up to 640 euros - limited to 90 percent of the purchase price. Owners receive up to 240 euros for plug-in solar devices, up to a maximum of 30 percent of the price shown on the invoice.

The invoice price to be recognized includes solar modules, micro inverters, cables, plugs and, if applicable, mounting materials. Shipping costs and other extras, such as electricity meters (smart meters) or battery storage systems, must be deducted from the invoice amount. An invoice that only shows a total price for a set of solar modules and storage cannot be taken into account, as in these cases the storage portion cannot be deducted from the invoice amount. The plug-in solar device/balcony power plant is not eligible for funding in this case.

Technically, the  safety standard of the German Solar Energy Society DGS 0001:2019-10 (opens in a new tab) is recommended. Please note that the landlord or the homeowners' association (WEG) must agree to the installation of the plug-in solar devices and that you are responsible for ensuring that they are securely fastened (liability).

In the case of listed buildings, a monument permit in accordance with § 9 DSchG NRW must also be obtained from the lower monument authority for plug-in solar devices. Please note that an approved grant can only be paid out if the Lower Monument Authority actually grants permission. In this respect, you should wait for the result of your monument application before purchasing a plug-in solar device. Regulations from design or conservation statutes must also be observed.

As the market situation is very dynamic, it is permissible to change the provider or model of the plug-in solar device after receiving the approval notice if the offer submitted in the application is no longer available. It is always important that the maximum permissible feed-in power of the micro inverter (currently 800 watts) is not exceeded.

For the years 2023/24, the funding guideline stipulates a 25 percent quota for plug-in solar devices. This means that one out of a total of four million euros of the planned funding budget is reserved for plug-in solar devices.

Photovoltaics on the roofs of apartment buildings with four or more residential units (funding module M2) and on all façades (funding module M4) are subsidized with 300 euros per installed kilowatt peak in order to stimulate the urgently needed expansion. In subsidized residential construction, there is an additional bonus of 200 euros per full earmarked year (subsidy module M3). For listed buildings (funding module M5) and non-residential buildings such as offices, commercial buildings or cultural facilities (funding module M6), the subsidy is 200 euros per kilowatt peak.

In the segment of residential buildings with up to three residential units, the photovoltaic subsidy of EUR 100 per installed kilowatt peak has only been granted since 1.1.2023 if the applicants fully occupy the roof areas suitable for solar use (subsidy module M1) - instead of only optimizing the solar power system for a high proportion of self-consumption.

Full roof occupancy within the meaning of the funding guideline is achieved if the installer confirms in writing (see form below) that the installed photovoltaic system is designed to maximize solar power production - on all gable and monopitch roof surfaces with south/southwest/west/southeast/east orientation (100°W-NW over 0°S to 100°E-NE) and on all flat roofs with 0-20° roof pitch (angle between the roof and the horizontal).

Excluded are areas that may not be used for solar energy due to public regulations (e.g. fire protection), areas with solar thermal collectors and areas that are completely shaded all year round.

On January 1, 2023, an attractive subsidy of 200 euros per kilowatt peak was introduced for ground-mounted photovoltaic systems - including, for example, solar power systems on parking lots, in agriculture or in private gardens (subsidy module M8). However, this usually requires planning permission - and possibly a change to the land use plan and the creation of a development plan.

If you green the roof under your photovoltaic system at least extensively, you can apply for a bonus of 100 euros per kilowatt peak (funding module M10). The green roof cools your building and the neighborhood and is therefore part of the adaptation to climate change. The photovoltaic system has a higher efficiency due to the cooling. When combined with green roofs, it is a condition that the green roof remains permanently functional, for example by elevating the photovoltaic modules.

Tip: You are also welcome to use our greening subsidy program for any green roofs or façades. This is also available to you independently of the installation of a photovoltaic system. If you implement photovoltaics and greening on the same partial roof area, you can even use both the Greening and the Solar Bonn funding programs.

Tenant electricity models with an EEG tenant electricity surcharge (in accordance with EEG Section 19, Section 21 (3) and EnWG Section 42a) are made even more attractive by the municipal subsidy of EUR 10 per kilowatt peak and per residential unit (subsidy module M9). For example, anyone who installs 10 kilowatts peak for 10 residential units will receive a bonus of 1,000 euros. With 30 kilowatts peak and 50 residential units, the bonus would already be 15,000 euros.

On the basis of Solar Package 1, which came into force on May 16, 2024, the "community building supply" (in accordance with Section 42b EnWG) is also subsidized with a grant of 10 euros per kilowatt peak per residential or commercial unit (subsidy module M9).

As part of the preliminary planning for the installation of a solar system, you can apply for funding for the inspection of the roof for tightness and / or static load capacity (funding module M7). This involves an assessment of the statics of the roof structure and, if applicable, the building underneath, including the roof structure, a description of the additional roof loads that would be permitted by a photovoltaic system and, if applicable, a description of the measures required to upgrade the roof for the installation of a photovoltaic system.

The assessment of the condition of the roof and the evaluation of whether it is recommended to install a photovoltaic system without prior roof renovation is also eligible for funding. These "PV ready" roof assessments are subsidized with 80 percent of the costs (max. 1,000 euros) - but only for existing buildings whose construction or last roof renovation was completed before December 31, 2012.

As the use of solar energy is increasingly becoming standard in new buildings and the introduction of a solar obligation is also on the horizon in NRW, the city of Bonn no longer considers incentives for new buildings to be necessary. The available public subsidies are therefore focused on existing buildings with construction completion by December 31, 2021.

If you would like to install a solar system (photovoltaic, plug-in solar device/balcony power plant, solar collector) on a listed building or in a listed area, you must submit the permit from the Lower Monument Authority by the time you apply for funding in accordance with Section 9 DSchG NRW at the latest.

However, in order to speed up the overall procedure, the funding application can be submitted before the monument permit is issued. However, you must wait for permission to be granted before purchasing, commissioning or installing your solar system. This is because the Lower Monument Authority can refuse permission to install the solar system for reasons of monument protection or possibly impose conditions (e.g. color, arrangement, mounting of the modules).

The application is made via the online form linked here and can be made either before or after the commissioning, purchase or installation of the solar system - but no later than three months after the final invoice. As long as no notice of approval has been received, the commissioning or purchase is at your own financial risk, as the application for funding may be rejected if the funding requirements are not met or the funding program has expired.

If you decide to use a different solar installer after receiving the approval notice, this is also permissible. If the actual size of the solar system is smaller when the subsidy is called up than envisaged in the approval notice, you will receive correspondingly less money - you do not have to submit a new application. If your solar system becomes larger than previously planned when you change installer, you can submit a second application for the additional system size - in accordance with the then applicable subsidy conditions.

All photovoltaic systems that are connected to the public grid must be registered. This applies to photovoltaics on buildings, facades and open spaces as well as all plug-in solar devices (such as balcony solar power plants). On the one hand, they must be registered with the  grid operator Bonn Netz GmbH (opens in a new tab), and on the other hand in the  market master data register of the Federal Network Agency (opens in a new tab). Your solar installer can help you with this.

Since the Solar Package I came into force, plug-in photovoltaic devices with a feed-in power of up to 800 W no longer need to be registered with the grid operator. The grid operator is automatically informed when you register in the market master data register.