Supported by solar modules that plug into the grid, you can generate your own solar power as a tenant or a homeowner. We will keep you updated on areas of focus.

Brief summary of the most important information:

• Your own balcony or terrace can generate solar power and use it to power your household.
• Grid plug-in solar modules produce electric power for personal use, but are not intended for grid integration.
• Balcony modules systems are safe and financially viable in the long term.
• Certain overly complex rules and requirements still apply, but this should not be a concern to you.
• Simplification measures are already being discussed, which, unfortunately, are still not applicable in practice.

Can we expect simpler grid plug-in rules for solar modules any time soon?

On 11 January 2023, the Association for Electrical, Electronic & Information Technologies (VDE) in Germany has published a position paper, calling for simpler rules for plug-in solar devices. Consumer exchanges have welcomed pending simplifications. Currently, the propositions such as the adoption of the Schuko plug, the removal of the mandate for grid operator registration, and the enhancement of the power threshold from 600 to 800 watts (alternating current) are merely recommendations presented in the VDE position paper. Therefore, they are not yet valid and enforceable.

The The Federation of German Consumer Organisations (Verbraucherzentrale Bundesverband – vzbv) also recommends the use of Schuko plugs.

Important information: Photovoltaic and battery energy storage systems are subject to 0% VAT since 1 January 2023. This zero percent also applies to grid plug-in solar modules.

1. What is a solar plug-in module and how does it work?

Do you have a balcony or terrace? If the answer is ‘yes’, then you can generate your own solar power and you can be actively involved in the energy transition – with the support of a solar plug-in model. These small photovoltaic systems are often also called mini solar systems, plug & play solar systems, or balcony power plants, as they can be mounted on the balcony railing. This, however, is not a system in the technical sense, but rather a power generating household appliance.

What can the solar plug-in module do? The solar module generates electricity from the sunlight, which an inverter converts into household electricity. It connects directly to an existing electrical circuit in the home. The simplest case is to plug in to an existing outlet.

The energy from the solar module is channeled directly to a conveniently placed outlet, such as an outlet on the balcony. This energy can then be distributed in your home, powering essential appliances like your television, refrigerator, and washing machine, connected to various other outlets within your living space. The electricity meter would indicate reduced consumption, as less electricity from the public grid is required. If the balcony generated electrical power cannot power household appliances, grid electricity is used instead.

Without a connection to the grid, solar modules do not produce electricity. When camping or on a garden plot, you can instead use the so-called  island systems with a battery and a different inverter type.

Solar plug-in modules usually consist of 1 or 2 standard solar modules and an inverter. Additional components are added, depending on the equipment.

1. Solar power modules: The grid-connected solar power unit consists of one to two solar modules. A module has rated power of approximately 300 W, with dimensions 1 x 1,70 m and a weight of up to 20 kg. Some systems are also comprised of several smaller modules.

2. Inverter: It is integrated into the solar module or attached separately, for example to the module frame.

3. Connecting cable: The cable leads from the inverter to a suitable external outlet.

4. Function Check: With a power meter – with or without an Internet connection – you can measure how much electricity is being produced.

5. Secure installation: Solar modules are installed using appropriate installation materials to safely withstand wind and weather conditions. Check in advance whether the selected solar modules can be installed at the planned location. Not all modules are appropriate for every balcony, and the consent of the landlord or the condominium association is required.

Solar modules: Standard modules measure about 1 meter by 1.7 meters, weigh about 20 kilograms and provide a rated power ranging from 350 to more than 400 watts. Furthermore, the selection includes glass-free solar modules or compact size solar modules, which are very suitable for easier installation, for example on a balcony.

Inverter: The inverter houses the electronic components that transform the direct current generated by the solar module from sunlight into alternating current. This conversion enables the electricity produced to be directly integrated into the home’s electrical system, allowing for immediate use by standard household devices. This modular inverter meets all the technical and safety requirements that larger appliances have to meet. It is generally suitable for outdoor use.

Connection to the grid: Connection to the mains happens via a plug cable. It is generally not anticipated to have a permanent connection, allowing the solar model to be turned on or off anytime and relocated, without needing to hire an external electrical installation provider. You can find the plug-in connector in the manufacturer's specifications. Two options usually exist – the special Wieland-type plug or the Schuko plugs, commonly used in households. In fact, it does not matter which of the three phases of the grid a solar module is connected to; electricity is also used by the devices in the other two phases.

Solar module installation: Special attention should be paid to the solar module installation. The installation site and materials must be suitable for this purpose. You can find information about this in the manufacturer's specifications (operating instructions). Most companies also sell ready-to-assemble kits. The primary priority here is to ensure that the solar module is not susceptible to wind damage or collapse because of its own weight.

Monitoring: Using a suitable metering device to check the correct functioning of the solar module and the amount of energy it delivers is recommended. In some inverters there are additional devices that take over this function. Otherwise, you can use socket meters or measuring sensors via WLAN or Bluetooth.

Battery energy storage: Solar electricity is not stored in the solar module, but is fed into the utility grid and consumed directly. Individual producers occasionally include small rechargeable devices in their product range. However, there have not been any economically viable products so far. Therefore, we do not recommend the use of batteries to store energy for solar modules.

2. What is the difference compared to a PV system?

Contrary to photovoltaic systems, the notably smaller solar modules intended for grid integration are designed for private individuals with the ability to handle their own set-up, connection, and usage. You can also create your registration with the grid operator and the Market Master Data Registry. Mini solar systems can also be easily dismantled and used elsewhere, for example when moving house. Their power is up to 600 watts (inverter power).

Photovoltaic systems on private homes, on the other hand, have a capacity between 3 and 20 kilowatts (kWp). The installation and maintenance of the constituent components and the technical reports and registrations with the local grid operator need to be provided by a specialized firm. The solar power system is firmly set up for ongoing use and can only be dismantled and moved to a different building at considerable expense.

In this video you can see what a solar module looks like in operation and the experiences of balcony power plant owners:

3. Is the solar module suitable for my home?

Normally the solar plug-in module is suitable for apartments with

• a balcony; or
• a terrace; or
• covering roof surface, respectively in front of a window, garage roof; or
• surface of an external wall facing the sun.

The grid plug-in solar module is much more cost-effective than a photovoltaic system and can therefore be financed by low-income individuals.

You can also install a solar module on the terrace or in the garden. When you move, you can simply take the device with you.

The following applies to rentals and owned homes: If you wish to attach the solar panel on the edge of your balcony or the wall of your residence, it is typically required to obtain approval from the owner or the owners’ collective. Since the Home Ownership Act (WEG) was amended in 2020, this no longer requires unanimity, only majority approval.

• Be advised that in special cases, historic preservation regulations may be contradictory to the project.
• For example, in close proximity to buildings listed as cultural monuments; or at the center of a listed site; or if building regulations prevent the project implementation. Keyword: Top glazing.

4. Are solar modules safe to plug in?

The devices are extremely safe overall. By the end of 2021, more than 190,000 such systems are in operation in Germany. So far, there is no known case of material damage or human casualties. This is due to the fact that the equipment used is very sophisticated, as it utilizes the same professional grade components as professional photovoltaic systems. Only standard-compliant produced and tested components may be used.

Solar plug-in modules are safe if the modular inverters used meet the requirements for regular photovoltaic system inverters. The installation standard additionally requires the electrician to confirm the circuit's ability to supply the grid with solar power.

To begin with, it is advised to only connect one solar module (also referred to as inverter) to a single plug or circuit. Connecting multiple modules via multiple sockets would be hazardous.

A product standard  for device testing and certification is currently in development. The DIN Consumer Council and the Consumer Advice Center are also involved in this process; a publication on this topic was expected in 2022 and has now been pushed back to 2024. Until its publication, you can refer to the Safety Standard published by the German Solar Energy Society (DGS), as an example.

In addition, you have to follow the device manufacturer instructions for connection and use. They contain know-how on how to securely fix the solar module and the inverter at the the intended place for installation.

5. What are the dimensions of the plug-in solar modules and what size is the right one for me?

By plug-in solar modules, we mean 1 to 2 solar modules with an inverter that are connected to a household's electrical circuit.

These can be 1 to 2 standard solar modules (measuring about 1 x 1.70 m) of an up-to-date design, which typically have a power rating ranging from 350 and 420 W each. Over the next few years, the electrical performance of standard modules will continue to improve.

The specified 600 watts refers to the power of the inverter connection to the mains (AC). It is also possible to use 2 modules with a power of 340 W each, or 2 modules with a power of 420 W each, provided that the inverter connection power does not exceed 600 W.

Alternatively, smaller format and lighter solar modules are also suitable, which are easier to attach to balcony railings, for example. They have a power range from 50 to 150 W and 2 to 4 of them can be connected to a single modular inverter.

Tip: If you want to use as much solar energy as possible for personal consumption and prevent power consumption from the grid, we recommend 200 to 400 W, which is usually the standard solar module. If you want to produce more solar energy, you can also consider 2 standard solar modules.

In principle, photovoltaic systems can also be set up to incorporate more power. Concurrently, solar modules that have an output of 2,400 watts are also available, but their inverters maximum output is also 600 watts. Consumer advice centers advise against this, due to the high input costs and the low power use permitted due to deregulation.

In our view, higher power modules without an inverter limit should be designed as a proper photovoltaic system. However, this is the last possible stage for a qualified electrician to check all the technical prerequisites of the electrical connection and to register the device with the grid operator.

However, the higher costs of installing a large photovoltaic system are financially justified only for significantly larger system outputs, exceeding 3 kilowatts.

This content has been prepared by the North Rhine-Westphalia and Rhineland-Palatinate user centers for the German user Center Network.

Source: Steckersolar: Solarstrom vom Balkon direkt in die Steckdose