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Conditions for connecting a photovoltaic system to the power grid in Germany.

2023-07-03
Application and Inquiry for Injection of Solar Power

Application and Inquiry for Injection of Solar Power

For smaller solar installations, the electricity is injected through the house connection. However, for larger installations with a capacity of 30 kWp or more, an application for grid connection (application for injection) must be submitted to the local energy provider before the solar system is installed. Please note that the review of the application and required documents will take time, but will not exceed eight weeks. It is generally recommended to include this step in the planning phase as early as possible to meet the intended commissioning deadline.

Timeline and Process for Handling a Grid Connection Request according to §8 Paragraph 5 EEG
Process Step Responsible Party Duration
Inquiry for Grid Connection Customer
Response with Information on Required Documents for Technical Assessment Energy Provider Approximately 5 working days
Compilation and Submission of Required Documents for Technical Assessment Customer
Preparation of Technical Assessment and Response Energy Provider Up to 8 weeks
Compilation and Submission of Required Documents for Connection Offer Customer
Connection Offer Energy Provider Up to 8 weeks

In the application for injection, the maximum achievable nominal power should be requested. The indicated value can be subsequently adjusted downwards if a smaller nominal power is realized. The approval for the injection of solar power remains valid.

The energy provider then conducts a network compatibility assessment and checks if the existing house connection is sufficient for your photovoltaic system. This is usually the case for small and medium-sized installations on single-family houses. However, for larger installations, it may be necessary to modify the network connection. In such cases, additional network connection costs should be expected.

In addition to an application, project planners can also make a general inquiry to the local energy provider for an injection commitment. However, this approach is generally not recommended when there is a specific project intention, as an inquiry for injection does not constitute a legally binding decision, unlike an application for injection.

While an injection commitment is usually granted, there may be cases where the energy provider deems the network compatibility as not feasible. In such instances, the energy provider is obliged, according to §8 of the EEG, to expand the local network capacity.

Overview of Documents for the Application of Connecting a Generation System to the Low-Voltage Grid
Application Documents
Registration for Grid Connection - ANA Electricity
Application for Generation Systems - Data Sheet for Self-Generation System (SGS)
Data Sheet for Generation Systems
Commissioning Protocol (documentation of the commissioning of the generation system by the electrical installer - Declaration of Commissioning for a Generation System (SGS))
Measurement Concept for Feed-in (common feed-in variants and associated measurement setup)
Circuit Diagram / Wiring Diagram of the entire electrical system including all components used
Dimensioned Site Plan of the house or the installation
Certificate of No Objection for the Generation Unit according to VDE 4105
Conformity Declaration for Grid Protection according to VDE 4105
Roof Layout Plan as a sketch for photovoltaic systems
Data Information Sheets for the modules and inverters or for the CHP system
Copy of the current installer ID of the responsible installer
Solar installations under 30 kWp without radio ripple control receivers require a confirmation of limiting the power to 70% of the installed module capacity

Your electrical installer or solar system provider can assist you in providing the necessary documents and with the application process. During the quotation phase, inquire about any additional costs related to the aforementioned procedures and whether your solar installer will handle these formalities on your behalf.

Selecting an Appropriate Grid Injection Point

The boundary of ownership to the supply grid is referred to as the handover point. For smaller solar installations, the connection box serves as the handover point, connecting the house and the solar system to the public power grid. For example, in the case of ground-mounted systems, the grid operator determines the most favorable injection point during the network compatibility assessment, where solar cables will need to be laid from the solar system. The installation operator is responsible for the costs of connecting to the nearest injection point.

However, if an injection point is assigned further away than the nearest one, the energy provider is obliged to cover the resulting additional costs. If solar cables need to cross third-party properties for the installation to reach the injection point, a permit agreement must be concluded with the property owner. If you plan to inject solar power from your system, it is advisable to address such circumstances in advance.

Technical Components for Solar Power Injection

Inverter

The inverter is the most crucial technical requirement for grid injection. Since photovoltaic systems produce direct current (DC), it must be converted into alternating current (AC) before injection into the power grid. There are different types of inverters used depending on the size and characteristics of your solar system.

  • String Inverter: Injects solar power through one or more strings, suitable for smaller photovoltaic systems with consistent external conditions.
  • Module-level Inverter: Used when individual modules have different orientations or are subject to shading. Each solar module has its own inverter.
  • Multi-String Inverter or Hybrid Inverter: Used for specific applications.
  • Central Inverter: Commonly used in large-scale solar installations, offering maintenance advantages due to its modular design.

The inverters should comply with IEC 77 standards and have voltage drop protection to prevent a failure of the photovoltaic system. When selecting an inverter, European efficiency is an important factor to ensure the profitability of your solar system.

Feed-in Meter

For accurate billing of the solar power injected into the grid, a feed-in meter, also known as a generation meter, is required. It measures the amount of injected solar power, based on which the grid operator disburses the EEG (Renewable Energy Sources Act) remuneration.

You can obtain the feed-in meter from the grid operator for a fee, or alternatively, purchase your own meter from a specialized retailer. Ensure that the meter has a reverse flow lock to ensure it stops counting when consuming power from the grid. The feed-in meter can be easily installed in a meter box.

The recorded data on electricity generation and solar power injection also serve to verify the performance of your system. If there is an unexpectedly low injection, it is advisable to have your photovoltaic system inspected by an expert to identify possible damages to the technical components or modules.

Injection Management

Currently, an energy manager is mandatory for almost all solar installations. For larger solar installations, the grid operator must be able to remotely reduce the grid injection if your photovoltaic system is overloading the grid. Therefore, larger systems require an energy management system that can not only remotely control the injection but also send the current injection data to the grid operator.

Operators of systems up to 25 kWp had the option to choose between a constant 70% reduction at the inverter or the installation of a ripple control receiver for remote control of PV systems. New solar installations up to a size of 25 kWp, installed since the amendment to the EEG 2023, are exempt from the obligation to limit their effective active power injection to 70%.

This regulation aims to improve grid control. If many solar installations are running at full capacity at noon but there is low household consumption, the grid operator must be able to reduce the solar power injection to prevent overvoltage in the grid and a potential blackout. However, you do not need to worry about the grid operator shutting down your system and losing the feed-in tariff. For each kilowatt-hour of solar power that is not injected due to grid overload, you will be compensated by the grid operator according to the EEG.

Energy Storage

Energy storage systems, also known as PV storage, offer another option to avoid grid overload and vary the injection of solar power. In addition to optimizing self-consumption, they can also be used to avoid injection peaks around noon. Through intelligent and proactive charging behavior, energy storage systems do not charge completely with excess solar power in the morning but can selectively reserve capacity for midday peaks. This is based on an automatic synchronization of weather and consumption data.

By reducing the injection capacity during peak times, the need for additional grid expansion, especially at the low-voltage level, decreases. Therefore, only grid-friendly energy storage systems that can smooth out PV injection peaks are currently supported.

Note: This text is for informational purposes only and should not be considered legal advice. For accurate information and specific requirements related to energy storage and solar installations, it is recommended to consult a specialized expert or legal advisor.

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