Grid connection for solar parks — the most common bottleneck
In short: The grid connection determines the maximum plant size and, in many regions, whether a park can be realised at all. Before any serious project development comes a grid connection pre-application (Netzanschluss-Voranfrage) with the responsible distribution system operator. In regions with grid bottlenecks, waiting lists of 12 months and more are realistic.
Voltage level by plant size
| Plant size | Typical connection level |
|---|---|
| < 100 kWp | Low voltage (Niederspannung, NS) |
| 0.1–10 MWp | Medium voltage (Mittelspannung, MS, usually 20 kV) |
| 10–100 MWp | Medium voltage with a dedicated transfer station, possibly high voltage (Hochspannung, HS, 110 kV) |
| > 100 MWp | High voltage / extra-high voltage via a transformer substation |
The exact threshold and availability depend on the specific grid area — clarifying this in advance is mandatory.
The pre-application — what it delivers
On request, the distribution system operator (Verteilnetzbetreiber, VNB) examines:
- Available connection capacity at the nearest transfer point.
- Necessary grid expansion measures (transformer upgrade, line reinforcement).
- The connecting party's cost share under the NAV / NAV-StromGS (low-voltage connection ordinance).
- Reservation terms (deadline, possibly a fee).
The pre-application is often free of charge or carries moderate fees — the binding reservation (the "grid connection point commitment", Netzverknüpfungspunkt-Zusage), by contrast, often costs several thousand to tens of thousands of euros depending on the VNB.
Typical cost blocks
- Cable route from the park to the transfer station: 100–250 €/m, depending on soil type and cross-section.
- Transfer station: 80,000–250,000 €, depending on power class and switchgear configuration.
- Transformer station(s) in the park: 30,000–80,000 € per station.
- Possible medium-voltage reinforcement (VNB share): can run into six or seven figures if the grid is locally insufficient.
- Connection fees according to the VNB's tariff.
Rule of thumb: 5–10% of the total investment goes to the grid connection; in grid-constrained regions considerably more.
Solar park grid connection — voltage levels, cost blocks and bottleneck warning
What project developers can do
- Ask early: submit the pre-application as soon as the site is realistically available.
- Check several transfer points — sometimes a longer cable to the next substation pays off.
- Plan for scalability: size the transfer station for possible repowering / expansion.
- Factor in storage: a battery storage system can smooth grid feed-in and reduce the required connection capacity.
- Coordinate with other developers — bundled connections reduce the cost per connecting party.
Frequently asked questions
Who bears the cost of grid expansion?
Under the NAV rules, the costs are shared — the connecting party pays the customer-specific share (cable route, transfer station), the VNB pays the share attributable to general grid expansion. In the event of a dispute, the Bundesnetzagentur (Federal Network Agency) is the point of contact.
What if the nearest connection is too far away?
Long cable routes (e.g. 5 km) are fundamentally feasible but tip the economics — a rule of thumb: from a distance of 2–3 km onwards, a critical economic review using the LCOE calculator is worthwhile.
Can I press the VNB?
The right to a grid connection is statutory (§ 17 EnWG, NAV), but the processing deadline is not hard. In case of inaction, file a complaint with the Bundesnetzagentur — it works, but it takes time.