Installing a balcony power plant: How to mount it on the roof easily and safely

The energy transition is not just happening in large solar farms, but directly above our heads. Installing a balcony power plant on the roof is the first step towards solar independence for many homeowners and tenants. However, while the name "balcony power plant" suggests simple installation on a railing, roof mounting often offers significantly better yields due to optimal sun alignment. In this guide, you will learn step-by-step how to safely and efficiently install your own power plant on the roof.

Balcony Power Plant on the Roof: Smart Entry into Solar Energy

A balcony power plant – often legally referred to as a plug-in PV system – is far more than just a trend. It is a democratization of energy generation. Roof mounting offers a decisive advantage over the balcony variant: the tilt. While balcony railings are often vertical, roof mounting allows for a tilt of about 30 to 45 degrees, which massively increases the efficiency of the modules. For many, this is the "smart entry" because the acquisition costs are low, but the yield over the 20-year lifespan leads to a significant reduction in electricity costs.

Requirements for Roof Mounting a Balcony Power Plant

Before the first roof hooks are set, the foundation must be right. Not every roof is suitable for a PV system.

• Check statics: A solar module, including the substructure, weighs about 20 to 25 kilograms. For two modules, that's 50 kg plus wind load. Your roof (especially for carports or garden sheds) must be able to support this load permanently.

• Roof condition: Is the roof watertight? If the roofing (tiles, trapezoidal sheet metal) needs to be renovated soon anyway, you should do that before installation.

• Orientation and shading: A south orientation is ideal, but east-west systems are also highly efficient. Important: Make sure that no chimneys, dormers, or tall trees shade the modules, as this can cause the performance of the entire system to drop significantly.

• Permissions: While tenants often need the landlord's permission, owners have it easier. Nevertheless: For listed buildings, always check local regulations.

Observe the Permitted Power Limit for Balcony Power Plants

Germany has massively simplified the expansion of small solar systems with the "Solar Package I". The current limit for simplified registration is a inverter output of up to 800 watts.

The installed module output (the sum of the nominal power of the solar panels) may now be higher (e.g., 1000 W or 1200 W), as long as the inverter limits the feed-in to 800 watts. This is useful to operate the inverter as close to its full load as possible, even on cloudy days. When purchasing, make sure that the inverter has a certificate according to VDE-AR-N 4105. This is your safety guarantee for operation in Germany.

Is it Permitted to Install and Connect Your Balcony Power Plant Yourself?

The short answer is: Yes, but with common sense.

As an owner, you are allowed to perform the mechanical installation (drilling, screwing, laying the substructure) yourself. The "connection" is also extremely safe for plug-in systems today. Previously, a special Wieland socket was mandatory; today, operation via a normal grounded socket (Schuko) is permitted, provided an appropriate inverter with NA protection is integrated.

Important note: If you feel unsure about the electrics, consult an electrician. Work on the fuse box (e.g., meter replacement or installation of smart meters) is generally a task for a specialist company. Safety always takes precedence over savings.

Step-by-Step Guide to Mounting Your Balcony Power Plant on the Roof

Installation differs depending on the roof type (tiles or trapezoidal sheet metal). Here is the procedure for a typical tiled roof:

1. Planning and safety: Working on the roof is dangerous. Use approved scaffolding or appropriate fall protection.

2. Install roof hooks: Carefully remove the roof tiles at the planned locations. Screw the roof hooks directly into the rafters. Make sure that the hook does not rest on the tile, but has enough play so that the tile does not break.

3. Mount the rails: Fasten the aluminum profiles to the roof hooks. These form the basic structure for the modules. Align the profiles with a spirit level.

4. Wiring: Connect the solar modules to the DC cables of the inverter. Make sure that the cables do not lie loosely on the roof tiles (risk of chafing!), but are fixed in cable ducts or with UV-resistant cable ties to the profile.

5. Insert modules: Lift the modules onto the profiles and secure them with the module clamps.

6. Commissioning: Route the AC cable (from the inverter) safely into the house, plug it into the socket, and register the system in the market master data register.

Frequently Asked Questions (FAQ)

1. Do I have to register the balcony power plant with the grid operator?

Yes. You must register the system in the market master data register of the Federal Network Agency. This process can be done online, takes only a few minutes, and is free of charge. An additional registration directly with the grid operator is often no longer necessary due to the new laws, but usually happens automatically through the register.

2. What happens in the event of a power outage?

Your balcony power plant has NA protection (grid and system protection). As soon as the public grid fails, the inverter switches off within a few milliseconds for safety reasons. Therefore, you cannot use your balcony power plant as an emergency power generator.

3. Can I operate the system in winter?

Yes, solar systems also produce electricity in diffuse light and cloudy conditions. However, the yield in winter is significantly lower than in summer due to shorter days and lower sun angles.

4. Do I need a new electricity meter?

Due to Solar Package I, it is now permitted to operate the system even with old meters (Ferraris meters with a rotating disc), as these may temporarily run backward. Nevertheless, modern meters (mME) are gradually being installed by the grid operator, which makes the process even more convenient.

5. What is the lifespan of a balcony power plant?

The modules are extremely durable and often have a performance guarantee of 25 years. The inverter is the most sensitive component and usually has a lifespan of about 10 to 15 years before it may need to be replaced.