Warenkorb
Dein Warenkorb ist leer
Weiter einkaufen
The energy transition is no longer just taking place on the roofs of large industrial buildings or in huge solar parks, but directly on the railings of balconies across Germany. Balcony power plants (mini PV systems) are enjoying enormous popularity, as they offer tenants and homeowners alike the opportunity to actively reduce electricity costs. But with the boom in these plug-and-play solar systems, a technical term is increasingly coming into focus: zero export.
But how exactly does zero export work with a balcony power plant? Why is this topic of burning interest to so many system operators, and is the technical effort involved worthwhile? In this comprehensive guide, we illuminate all aspects – from the technical functioning to legal issues and economic viability in combination with a battery storage system.
What does zero export mean for a balcony power plant?
To understand the concept of zero export, you must first consider the basic principle of a balcony power plant. Normally, the solar system produces electricity that flows directly into the household grid. This electricity is immediately used by active consumers (refrigerator, router, stand-by devices). However, if the system produces more electricity at midday than the household consumes at that moment, the surplus electricity automatically flows unremunerated through the electricity meter into the public grid.
Zero export means that precisely this surplus into the public grid is technically prevented. The system is intelligently controlled so that the inverter of the solar system always produces and feeds exactly as much electricity into the household grid as the household needs in the same fraction of a second. The system's output is therefore dynamically throttled ("curtailed") as soon as a surplus threatens. The feed-in value to the public grid is thus always exactly zero watts.
Difference between a balcony power plant without feed-in and feed-in to the electricity grid
The main difference lies in the communication and control of the system.
With classic grid feed-in, the inverter of the balcony power plant operates "blindly". It converts the direct current (DC) from the solar modules as efficiently as possible into alternating current (AC) and pushes it into the house grid at maximum power – completely regardless of whether 100 watts or 2000 watts are currently being consumed in the house. Everything that is too much flows into the public grid via the household meter. Since feed-in tariffs under the Renewable Energy Sources Act (EEG) are generally not applied for conventional balcony power plants (up to 600W or 800W), this electricity is essentially given away to the grid operator.
A balcony power plant without feed-in (zero export), on the other hand, is an intelligent system ("Smart System"). It requires a measuring point directly at the house's main electricity meter. This measuring point (often a so-called smart meter or current sensor with clamp-on transformers) records the current flow in real time. If current flows out of the house, the sensor sends a signal to the inverter to immediately throttle its output. The essential difference is thus the transition from uncontrolled full production to demand-controlled real-time production.
How does the technical implementation of zero export work?
The technical magic behind zero export is based on a permanent data exchange. The setup typically consists of three main components:
-
The smart meter / sensor: This is installed in the fuse box (meter cabinet) directly behind the grid operator's official electricity meter. It measures every phase of the household precisely in watts.
-
The communication unit: The measured data must reach the inverter. This happens either via cable (RS485/Modbus connection) or wirelessly (WLAN, Zigbee, or proprietary radio protocols).
-
The dimmable inverter: The inverter receives the signal ("Attention, 50 watts surplus!") and shifts its operating point so that the solar modules produce less electricity, even if the sun is shining brightly. This process happens in milliseconds.
Why do many want to prevent PV feed-in through zero export?
The motivation to block feed-in usually has psychological, economic, and bureaucratic reasons:
-
The "giving away" factor: Many operators feel it is unfair to give away high-quality, green electricity to multi-billion-euro energy companies, who then theoretically resell it to their neighbors.
-
Avoidance of bureaucracy: In the past, some grid operators caused problems when old meters (Ferraris meters) ran backward due to the fed-in electricity. Although the legislator has now introduced relaxations here (such as Solar Package I), many operators want to avoid any discussions with the grid operator from the outset through zero export.
-
Technology enthusiasm: For many, the pursuit of self-sufficiency and optimizing their smart home is a fascinating hobby. Zero export is the first step towards a fully integrated energy management system.
BERATUNG STARTEN
Bereit für Dein eigenes Solarprojekt? Lass uns sprechen.
Unser Team hilft Dir, Speicher, Solarmodule, Wechselrichter und Zubehör passend zu Deinem Zuhause zusammenzustellen.
Persönliche Fachberatung