Cologne is one of the largest cities in Germany and a key location for our assessor work in Nordrhein-Westfalen. As the Rhineland metropolis, Cologne presents unique challenges: flood protection for battery storage systems near the Rhine, heritage protection in the historic Altstadt, and large flat-roof PV systems on former industrial brownfields. In every project, the TAB of RheinNetz form the technical backbone of our assessment work.
RheinNetz operates the grid in Cologne serving approximately 1.08 million inhabitants across roughly 12,500 km of grid. As a million-plus city, Cologne has highly varied grid conditions — from well-developed suburban areas in Rodenkirchen to heavily loaded inner-city networks in the old town.
Through its programme "Photovoltaik: klimafreundliches Wohnen in Köln", the City of Cologne funds PV systems on existing residential buildings at least five years old. Flat-rate grants range from EUR 1,500 (2 to 5 kWp) to EUR 2,500 (over 14 kWp), and from EUR 500 to EUR 1,300 for batteries with a ten-year warranty. Plug-in solar devices receive EUR 150, or EUR 300 with the KölnPass. The grant covers at most 60 percent of eligible costs and is capped at EUR 10,000 per building and year. Planning and commissioning must demonstrably be carried out by a specialist contractor (City of Cologne).
RheinNetz accepts registrations via its online feed-in portal, no earlier than six months and no later than six weeks before commissioning. The metering concept must be registered at least four weeks before start of operation. Since February 2025 RheinNetz has required the ZEREZ ID of the inverters. Several systems on the same property commissioned within twelve months count as one system (RheinNetz). This affects thresholds such as the 30 kW limit of the simplified procedure.
Under section 42a of the NRW Building Code, the solar obligation has applied to non-residential buildings since 2024, to new residential buildings since 2025 and to roof renovations starting from 1 January 2026. New buildings must cover 30 percent of the roof area; for single and two-family houses with roof renovation, 3 kWp is an alternative (Verbraucherzentrale NRW).
| Standard | Subject | Applies to |
|---|---|---|
| VDE-AR-N 4100 | Low-voltage connection | Meter location, service entrance, protection concept |
| VDE-AR-N 4105 | Generation on the LV grid | Mandatory for connection to the low-voltage grid |
| VDE-AR-N 4110 | Medium-voltage connection | Mandatory for connection to the medium-voltage grid |
| Supplementary TAB RheinNetz | Regional requirements | Grid area |
| DIN VDE 0100-600 | Initial verification | Every system before commissioning |
| Requirement | Specification |
|---|---|
| Meter type | eHZ in three-point mounting system |
| Surge protection | Type 1+2 combined arrester (mandatory for new systems) |
| SLS switch | Selective line protection switch upstream of the meter |
| Space reserve | Min. 1 slot for smart meter gateway |
| Equipotential bonding | Connection to main earthing busbar |
Balcony power plants up to 800 W can be registered with RheinNetz through a simplified process.
Cologne is located in the Amprion control area. The responsible transmission system operator (TSO) is Amprion GmbH, in charge of system stability and renewable feed-in in the extra-high voltage grid (220/380 kV).
| Level | Operator | Voltage Level | Relevance for PV/BESS |
|---|---|---|---|
| Transmission grid | Amprion | 220-380 kV | System stability, EEG feed-in |
| Distribution grid | RheinNetz | 0.4-20 kV | TAB, grid connection, meter location |
| Customer system | System operator | 0.4 kV (LV) | PV array, BESS, inverter |
Regional points we check when planning and assessing projects in Cologne:
Battery storage systems near the Rhine must be designed with flood protection in mind. In flood-risk zones (HQ100), BESS must be installed above the maximum flood level or in waterproof enclosures. This particularly affects districts such as Rodenkirchen, Porz, and the Altstadt along the Rhine.
PV systems in Cologne's historic old town require heritage protection approval. Modules must be visually unobtrusive — in-roof solutions or building-integrated PV are typically mandated. The proximity to Cologne Cathedral (UNESCO World Heritage) imposes additional constraints.
RheinNetz places particular emphasis on reactive power compensation for larger PV systems. Inverters must support cos(phi) regulation and Q(U) characteristic curves per VDE-AR-N 4105. Failure to comply is a frequent cause of commissioning delays.
Former industrial sites in Koeln-Ehrenfeld and Koeln-Muelheim offer large flat roof areas for PV. However, contaminated-site regulations and structural load assessments are often required before installation can proceed.
| Occasion | Our Service |
|---|---|
| Acceptance | TAB conformity, defect report |
| Dispute with grid operator | Independent technical evaluation |
| From 30 kWp or medium voltage | Supervision, grid compatibility assessment |
| Defects | DIN VDE 0100-600, thermography, EL |
| Flood zone BESS | Flood protection concept, placement assessment |
VDE-AR-N 4100 and 4105 (low voltage) or 4110 (medium voltage) plus supplementary TAB of RheinNetz GmbH.
Exclusively through a certified electrical contractor. Details: RheinNetz website.
Must comply with VDE-AR-N 4100 and supplementary TAB. Older cabinets (pre-2010): eHZ, surge protection, SLS. Cost: EUR 1,000-2,500.
Depends on system size and scope. Contact: info@pv-bess-assessor.com or +49 89 97 31 37 43.
For systems from 30 kWp, medium voltage, grid compatibility issues, disputes with the grid operator, acceptance of commercial systems.
We know the TAB of RheinNetz from daily practice. Get in touch.
Contact Us| Address | RheinNetz GmbH, Parkgürtel 24, 50823 Köln |
| Phone | 0221 178-0 |
| info@rheinnetz.de | |
| Website | RheinNetz — TAB |
We prepare PV and BESS assessments throughout Germany. The following pages summarise the technical connection requirements of the respective grid operator:
Augsburg Berlin Bielefeld Bonn Bremen Dortmund Dresden Düsseldorf Duisburg Frankfurt Hamburg Hannover Karlsruhe Leipzig Mannheim München Münster Nürnberg Stuttgart
Last updated: 2026-11-03 | Source: RheinNetz GmbH