A containerised storage system that is fully compliant in Germany cannot be trucked to Italy and switched on. The technical requirements overlap heavily — both countries implement the same EU network code — but the certificates, the forms and the registries do not transfer. What travels is the hardware. What does not travel is the paperwork that allows the hardware to energise, and without that paperwork the project has no connection agreement and no revenue.
The EU Rulebook Sorts You by Type, Then Each Country Re-Sorts You
Grid connection for storage in the EU starts with the Requirements for Generators, Commission Regulation (EU) 2016/631. It classifies every generating facility into one of four types by capacity and connection voltage, and the type determines how demanding the compliance obligations are.
| Type | Capacity (Continental Europe ceiling) | Connection voltage | Who this usually is |
|---|---|---|---|
| A | From 0.8 kW, below Type B | Low voltage | Residential and very small commercial |
| B | From 1 MW, below Type C | Usually MV | Most C&I and mid-scale storage |
| C | From 50 MW, below Type D | MV to HV | Large industrial, small utility |
| D | From 75 MW, or any plant at 110 kV | 110 kV and above | Grid-scale |
Those are ceilings, not fixed thresholds. Each national transmission operator is allowed to set lower boundaries, and several do. The consequence is that the same 500 kWh cabinet can be Type A in one country and Type B in another, with the heavier obligations that Type B brings — plant certificates, simulation models, compliance testing. Classification is a function of where you connect, not what you bought. And if the connection point is weak — low short-circuit ratio, high source impedance — the ratings that decide whether the system survives are a separate question from the paperwork; they are set out in the four ratings a weak grid tests.
The thresholds also differ by synchronous area, which matters for anyone building a repeatable product for multiple markets.
| Synchronous area | Type B threshold | Type C | Type D |
|---|---|---|---|
| Continental Europe | 1 MW | 50 MW | 75 MW |
| Great Britain | 1 MW | 50 MW | 75 MW |
| Nordic | 1.5 MW | 10 MW | 30 MW |
| Ireland | 0.1 MW | 5 MW | 10 MW |
| Baltic | 0.5 MW | 10 MW | 15 MW |
Ireland is the outlier that catches people: a 150 kW installation is already Type B there, while the same unit is Type A almost everywhere else on the continent.
Same Rules, Different Paperwork
The EU code harmonises what a plant must be capable of. Each member state owns how that capability is proven. If you sell across borders, budget for a distinct compliance package per country.
| Country | Core connection rules | What is specific |
|---|---|---|
| Germany | VDE-AR-N 4105 (LV), 4110 (MV, 1–60 kV), 4120 (HV) | NELEV ordinance requires unit and plant certificates; ZEREZ component-registry entry needed to connect |
| Italy | CEI 0-21 (LV), CEI 0-16 (MV), both aligned to RfG | Strict anti-islanding and interface protection (SPI) rules; storage explicitly addressed |
| United Kingdom | NESO Grid Code, G98 / G99 / G100 | Outside the EU framework entirely; separate application route and separate certificates |
| Spain | NTS implementing RfG | Conformity assessment runs as an accredited certification scheme |
| Netherlands | RfG via Netbeheer Nederland codes | Standardised compliance-verification document and PGMD process; widespread congestion |
Germany is the market where the paperwork most often becomes the critical path. VDE-AR-N 4110 — currently the 2023-09 edition — explicitly covers storage, and the NELEV ordinance requires both a unit certificate for the generating unit and a plant certificate (Anlagenzertifikat) for the installation as a whole. The plant certificate is issued against the specific site configuration, which means it cannot be prepared from a datasheet alone. It needs the single-line diagram, the protection settings and the transformer data.
Italy’s difference is procedural rather than technical. CEI 0-21 and CEI 0-16 are closely aligned to RfG, but the interface protection requirements are enforced with less tolerance for substitution, and the connection route depends on voltage level and network configuration in ways that are best confirmed with the operator before the design is fixed.
What Compliance Actually Produces
The output of all this is not a certificate on a wall. It is an operational notification — the document that allows the plant to energise and trade. The chain has four links.
- Type test certificates for the PCS and the storage unit, issued against the relevant standard. In Europe this is usually EN 50549, which turns RfG capability requirements into testable criteria for distribution-connected plants.
- Plant-level compliance documentation — the single-line diagram, protection settings, simulation models and control logic that show how the certified components behave together at this site.
- Submission to the network operator — TSO for transmission-connected or larger projects, DSO for most distribution connections, with the responsible party determined by voltage and configuration.
- Operational notification (EON or FON depending on jurisdiction) — the permission to energise. Without it, the equipment is installed and inert. And a plant that can energise is still not a plant that can export — export rights are a separate limit from connection permission, and they are frequently confused.
The commercial consequence of that chain is straightforward: the certificate is a property of the equipment, but the operational notification is a property of the project. A supplier can hand over a valid type certificate in a week. The plant certificate and the notification depend on the site, and they are usually what sets the schedule.
The German Number That Catches Mid-Size Projects
Germany sets its Type B threshold at 135 kW, far below the 1 MW Continental Europe ceiling. A mid-sized commercial battery that its owner assumed was a small installation is Type B under German rules, with the full set of Type B obligations attached.
This is not a technicality. Type B brings requirements for reactive power capability, fault ride-through, frequency response and controllability that Type A does not, and it brings the plant certificate process. A project sized at 200 kWh for peak shaving can find itself in the same compliance category as a 900 kW industrial system.
Confirm the national threshold, not the EU ceiling. The ceiling tells you what the regulation allows a country to require. The national threshold tells you what this project will actually have to prove.
Grid Connection Is Not CE Marking
These are two parallel regimes and passing one does not satisfy the other. Grid-code compliance is what allows the plant to connect and energise. CE marking and the EU Battery Regulation (2023/1542) are what allow the product to be placed on the market at all, covering safety, labelling, documentation and end-of-life obligations.
A storage system can hold every grid-code certificate it needs and still be non-compliant to sell in the EU if its battery documentation, labelling or recycling registration is incomplete. Buyers who treat these as one checklist discover the gap at customs or at the first regulatory audit, both of which are expensive places to discover anything.
The Queue Is Now Part of the Technical Problem
Connection capacity is no longer a formality that follows a good design. In several European markets the queue itself constrains what can be built and when.
Italy illustrates the scale. As of 31 May 2026, Terna’s connection platform recorded roughly 294 GW of storage connection requests — far beyond the country’s 2030 targets. In response, Decreto MASE 291/2026, in force from 9 September 2026, requires Terna to divide the transmission grid into microzones and calculate available capacity within each. The reform is legally in force, but the microzone boundaries and published capacity figures are still being rolled out through late 2026.
The Netherlands has the same problem in a different form: widespread congestion (netcongestie) means a connection may be offered on a flexible rather than firm basis, which changes the revenue model as much as the engineering. Germany and Spain both carry large pending pipelines with allocation rules under revision.
The practical implication for a buyer is sequencing. Verifying that a site has connection capacity, and on what terms, has to happen before equipment is ordered, not after. A container sitting on a pad waiting for a connection agreement is a working-capital problem that no amount of technical compliance solves.
What to Prepare Before You Order Equipment
Customs clearance and grid connection are two different gates, and passing the first does nothing for the second — the five documents that clear a container are not the documents that energise it. What follows is the grid side. The documents that take longest are the ones that depend on the site, not the product. Prepare these first.
- Point of connection and voltage level, confirmed in writing by the network operator, with the responsible party named — TSO or DSO.
- Import and export limits, including any curtailment or flexible-capacity conditions attached to the offer.
- Single-line diagram covering the storage unit, PCS, transformer, switchgear, protection and metering, at the level of detail the operator requires for the plant certificate.
- Protection settings and coordination study — the most common cause of a failed witness test is protection that was never modelled.
- Type test certificates for the PCS, against the standard the destination country accepts, with the certificate scope matching the exact model and firmware version being supplied.
- Simulation models in the format the operator requires. A certificate without a model is increasingly not enough for Type B and above.
Two sequencing mistakes account for most delays. The first is ordering battery racks before the utility has confirmed feeder capacity, which leaves equipment stranded if grid reinforcement turns out to be required. The second is treating the plant certificate as a post-installation formality, when in practice it is a design-stage document that constrains the single-line diagram.
Frequently Asked Questions
Can a BESS certified in Germany be installed in Italy?
The hardware can. The compliance package cannot. Italy requires its own connection application under CEI 0-21 or CEI 0-16, its own interface protection documentation, and its own operational notification. Type test certificates may be reusable where the standards align, but the plant-level documentation and the connection process are country-specific.
What is the difference between Type A, B, C and D under RfG?
The types are capacity and voltage bands that set how demanding the compliance obligations are. In Continental Europe the ceilings are 1 MW for Type B, 50 MW for Type C and 75 MW (or 110 kV connection) for Type D, but each country can set lower national thresholds — Germany’s Type B threshold is 135 kW.
Does grid-code compliance also satisfy CE marking requirements?
No. They are separate regimes. Grid-code compliance allows the plant to connect and energise. CE marking and the EU Battery Regulation (2023/1542) govern whether the product can be placed on the market, covering safety, labelling, documentation and recycling obligations. A project needs both.
What is an operational notification?
It is the network operator’s permission to energise and operate the plant, issued after the compliance documentation is accepted. Depending on jurisdiction it is called an EON or FON. Without it the equipment can be installed but not energised, so it is the document that actually gates revenue.
How long does the connection process take?
It varies too widely for a single number, because the queue and the allocation rules are the binding constraint in most markets rather than the technical review. Confirm the current process, queue position and any capacity-allocation reform with the responsible operator before fixing a schedule.
For the full document set and the questions to ask before booking freight, see the certification map in our downloads section.
Checking a European connection?
Send us the point of connection, voltage level and target country, and we will list the documents that project will be asked for — and which of them depend on the site rather than the equipment.