Balcony power plants – i.e., plug-and-play mini-photovoltaic systems for balconies or terraces – are experiencing a boom in Germany. In 2023 alone, around 300,000 new balcony power plants were installed. Consequently, owners frequently ask: When and where do you have to register a balcony power plant? This article provides an understandable overview of the registration requirements, current legal regulations (as of 2025), and offers practical tips for households wishing to start generating their own solar energy.
Introduction to Balcony Power Plants
A balcony power plant is a small photovoltaic system, usually consisting of one to two solar modules and a micro-inverter. Fed into the household grid via a socket, it can directly generate electricity for home use. Typically, no complex permits are required for installation, and thanks to simplified regulations, balcony power plants have become very popular. Especially tenants and apartment owners appreciate these plug-and-play solar kits to cover a portion of their electricity needs with their own solar energy.
However, even with mini-PV systems, a few legal requirements must be met – particularly regarding the registration of the system. Since 2024, these regulations have been significantly simplified. We will explain exactly what is required, who is responsible, and when you need to register your balcony power plant in the following.
Legal Situation and Registration Obligation in Germany
In Germany, balcony power plants are generally permitted, provided they comply with certain power limits. Since 2024, the module power can be up to 2000 watts (2 kWp), while the inverter may feed a maximum of 800 watts into the house grid. This limit was raised from the previous 600 W to 800 W by the federal government's "Solar Package 1" in 2024. This higher feed-in limit allows a balcony power plant to supply more solar power to its own grid – however, it remains important to comply with safety standards (an updated VDE standard for 800 W systems is expected by the end of 2024).
Registration Obligation: Anyone operating a balcony power plant in Germany is legally obliged to register it in the official Market Master Data Register (MaStR) of the Federal Network Agency. Since mid-2024, this single registration is sufficient – the previous dual registration obligation (additionally with the local grid operator) has been abolished. Therefore, it is no longer necessary to separately report the balcony power plant to the electricity grid operator. Instead, entry in the central register is sufficient; the Federal Network Agency then automatically informs the responsible grid operator about the new system.
Important to know: Registration in the Market Master Data Register is free of charge and can be done online. Every electricity-generating system – no matter how small – is assigned an entry here. With this, the legislator aims to maintain an overview of decentralized electricity generation. A balcony power plant is legally considered an electricity generation system, which is why the registration obligation applies. Violations can theoretically be punished as an administrative offense.
Further Requirements: In addition to registration, technical requirements must be met. For example, a bi-directional meter is usually required in the apartment, which can separately record grid feed-in and grid consumption. Old Ferraris meters without a reverse lock may only be operated temporarily. In practice, this means: After registration, your grid operator may exchange the meter if an old one is still installed. This exchange is usually free of charge for the system operator but ensures that excess solar power does not cause the meter to run backward.
Balcony power plants have also become attractive from a tax perspective: Since 2023, VAT is no longer charged on the purchase and installation of PV systems up to 30 kW – this also applies to mini-PV and PV storage. This saves private households 19% of the costs, which further favors the acquisition.
Who is responsible? Where do you have to register the balcony power plant?
For the registration of a balcony power plant in Germany, the Federal Network Agency is responsible, specifically its online portal Market Master Data Register (MaStR). All plug-in solar power systems must be recorded there. Operators register their system themselves in the MaStR – alternatively, an authorized person (e.g., an electrician) can take over. Only a few details are required: location address, system name (often simply "Balcony Power Plant"), date of commissioning, total module power, inverter power, and the meter number. Optionally, an existing solar storage unit can also be entered with its name, power, and capacity. Overall, the form was greatly simplified in 2024 so that even laypersons can register their mini-PV system without bureaucratic hurdles.
As mentioned, separate registration with the regional grid operator is no longer required since 2024. Once the system is registered in the MaStR, the obligations are considered fulfilled. The grid operator is automatically informed, so you do not need to take any additional action. If your grid operator still requests a separate registration form, this is probably a relic of old practice – according to current legal provisions, you can refer to the fact that the entry in the MaStR is sufficient.
Notification to the Landlord/Owners' Association: In addition to the official bodies, as a tenant or apartment owner, you should inform your landlord or the owners' association before installing a balcony power plant. A lot has changed legally here: In 2024, balcony PV systems were included as a "privileged measure" in apartment ownership law. This means that owners may install a balcony power plant without requiring unanimous consent from all co-owners. As a rule, a simple majority resolution of the owners' assembly is sufficient, provided no structural changes to the common property are necessary. There have also been improvements in tenancy law: Landlords may no longer refuse permission for a balcony power plant without a valid reason. Tenants now have a legal right to consent, provided safety requirements are met. Nevertheless, it is important to discuss your plans early – this often helps to address concerns (regarding mounting, building aesthetics, etc.). Written consent can also be helpful for insurance later on.
Where does the registration take place? Practically, registration is done via the Federal Network Agency's web portal. You can create a user account and register your system at www.marktstammdatenregister.de. Have the above-mentioned data ready; the input usually only takes a few minutes. After completing the registration, you will receive a confirmation and your MaStR number, under which the system is listed. Keep this data safe. If you dismantle your balcony power plant or move, you must also note the decommissioning or change in the MaStR.
When do you have to register a balcony power plant?
The timing of the registration is crucial. According to the Federal Network Agency, a balcony power plant must be registered at the latest within one month after commissioning. So, from the day your mini-PV system first feeds electricity into your home grid, you have a maximum of four weeks to complete the registration. Even better: Complete the registration immediately upon commissioning or even shortly before, so you don't forget this obligation. The online form can also be filled out while the system is being installed – then you enter the planned start date as the commissioning date.
Tip: Many manufacturers or retailers include instructions for registration with the balcony power plant. If available, use this help. Otherwise, an information sheet outlining the necessary steps can also be found on the MaStR website.
What happens if you do not complete the registration on time? – Theoretically, this constitutes a violation of §5 of the MaStR Ordinance and can be penalized with a fine. In practice, however, no cases have been reported so far where private balcony solar system owners were punished for failing to register. The authorities tend to focus on information and subsequent registration rather than penalties. Nevertheless: You should not rely on this. On the one hand, you are acting illegally, and on the other hand, other disadvantages could arise. For example, your grid operator could cause problems, or an insurance company might reduce benefits in the event of damage if the system was not registered. In short: Register your balcony power plant correctly – the effort is minimal, and you are on the safe side.
In summary: A balcony power plant in Germany must be registered within one month of its first connection. It is best to do it immediately upon commissioning online in the Market Master Data Register. This way, you comply with legal requirements and avoid potential risks from forgotten registration.
Advantages of a PV Storage Unit for a Balcony Power Plant (Optional)
A balcony power plant can in principle be operated without a battery storage unit – the solar power then flows directly to the currently running devices, and surpluses are fed into the public grid. However, many users consider purchasing a PV storage unit to benefit even more from their own solar power. Indeed, a battery storage unit offers several advantages:
• Higher Self-Consumption: A storage unit significantly increases the proportion of self-consumed solar power. Without storage, typical balcony power plants might use perhaps ~30–50% of their electricity directly in the household; with storage, self-consumption rates of up to 80% are possible. This is because midday surpluses are not wasted but are buffered for the evening. This means less grid electricity needs to be purchased at night. In short: More of your "own" electricity is used, which makes sense both financially and ecologically.
• More Independence: With a balcony power plant storage unit, you are less dependent on energy providers and rising electricity prices. While a single balcony power plant will never cover the entire household demand, a storage unit somewhat increases autonomy. In combination with the public grid, the battery can buffer demand in the evenings or when it's cloudy. With some advanced systems, even limited emergency power operation is possible in case of a power outage. However, balcony power plants are not designed for complete outage protection – the storage unit primarily serves to optimize consumption.
• Easy Retrofitting: Modern balcony power plant storage units are compact, modular, and often mobile. There are plug-and-play systems specifically designed for mini-PV – sometimes not much larger than a beer crate. These can also be accommodated in rented apartments (e.g., in a storage room) and taken with you when moving. Many storage units can be expanded by stacking additional battery modules if the balcony power plant is later enlarged. Installation is generally straightforward: the storage unit is either connected between the PV system and the socket or integrated into the house grid on the AC side, depending on the system.
• No Legal Disadvantages: Connecting a battery storage unit is permitted – no special permits are required. There is also no capacity limit for the storage unit itself. It is only important that the limits of 2000 W module power and 800 W feed-in power are still observed. A storage unit does not count towards the feed-in power, as it does not feed additional electricity into the grid but only buffers the existing solar power. Thus, the system remains legally a balcony power plant. The tax exemption also applies: Since 2023, battery storage units for PV systems are exempt from VAT, making the purchase cheaper.
Of course, a storage unit incurs additional costs. Therefore, every household should weigh whether the investment is worthwhile. With rising electricity prices and the discontinuation of feed-in tariffs (for balcony power plants in Germany, you usually do not receive compensation for excess feed-in), a storage unit is becoming increasingly attractive. It ensures that as little surplus electricity as possible goes unused into the grid, but rather ends up in your own battery.
Conclusion: A PV storage unit is a useful addition if you want to maximize self-consumption and achieve a certain degree of independence. It is legally unproblematic and technically easy to implement nowadays. Especially in combination with favorable conditions (0% VAT) and tariff-free operating obligations, balcony power plant storage units are becoming increasingly popular.
Conclusion and Outlook
A balcony power plant enables private households to generate their own solar power easily – and thanks to current regulations, it's easier than ever. The registration of such a mini-PV system is mandatory but not a major hurdle: Since 2024, a free online registration in the Market Master Data Register is sufficient, which must be completed within one month of commissioning. Anyone who registers their balcony power plant correctly complies with legal requirements and can then calmly let the sun work for them.
The bureaucratic effort surrounding it is also limited: Neither building permits nor elaborate approvals are usually necessary. Thanks to new laws, tenants and owners now have a right to balcony solar, as long as there are no serious objections. In combination with tax advantages (VAT exemption) and simplified installation, the current situation offers ideal conditions to start with a small PV system.
If you are now eager to generate your own electricity, check out NYLYN Solar. In the NYLYN Solar range, you will find complete balcony power plant kits, suitable PV storage units, and high-quality complete systems – everything you need to start your private energy transition. Get advice and become your own electricity producer!
