Installation of battery energy storage systems (BESS) on ground screws — European standards

Installing a battery energy storage system (BESS) on ground screws in the EU is governed by Eurocode 7 for the geotechnical design of point loads and standard EN 1990 for load combinations, while fire safety separation distances between containers are regulated by the national provisions of individual member states.

Two levels of regulation: foundation design and operational safety

Just as with timber structures, the rule of two areas of expertise applies to BESS as well. Geotechnical foundation design (screw pile, its length, load-bearing capacity, spacing) is covered by Eurocode 7. The structural design of the container frame and load combinations are addressed by EN 1990 and the subsequent Eurocodes for steel structures (EN 1993). The electrical and fire safety of BESS operations as a technological installation is a separate area, which in the EU is governed by the international standard IEC 62933 and national fire regulations — it is not directly related to foundation geotechnics, but the investor and designer must address it simultaneously.

Eurocode 7 — point loads from containers

Eurocode 7 (EN 1997-1, Section 7 — Pile foundations) applies to ground screws for BESS in the same way as to other types of loading. A detailed general overview of the standard can be found in a separate article: Eurocode 7 and ground screws.

Specific to BESS is the load profile:

Concentrated point load. Unlike a uniformly distributed load (e.g. for a PV mounting system), each ground screw beneath a BESS container transfers a substantially higher unit load concentrated at several support points. A structural engineer must verify the load-bearing capacity of the individual ground screw as well as the entire group (group effect in accordance with EC7 §7.6.2).

Combination of vertical and horizontal loading. Wind on the side wall of the container creates a horizontal component that the screw and supporting head must transfer together with the vertical load — design approach DA1 (combinations 1 and 2) is standard in the Czech Republic, Slovakia, Austria and Germany.

Documentation for each point separately. Due to the higher unit load, it is common with BESS to document the telemetry record (torque × depth) for every single ground screw rather than just a sample — this serves as a basis for the structural engineer and for investment insurance.

EN 1990 — load combinations

EN 1990 (Eurocode: Basis of structural design) specifies how to combine individual loads (self-weight, imposed load, wind, snow, and seismic action where applicable) into design combinations that both the foundation and the load-bearing structure must satisfy.

For the BESS container, the following are particularly relevant:

Permanent load — tare weight of the container and batteries (tens of tonnes depending on the type and battery chemistry)
Climate impact — wind load on the side panel, or snow on the container roof in locations with relevant snow loads
Exceptional load - in seismic regions (especially southern Europe) supplemented by Eurocode 8

The national annexes of individual EU countries govern partial load factors and combination rules — a project carried out in the Czech Republic cannot be transferred to Germany or Italy without modification.

IEC 62933 — safety of a BESS as a technological facility

International standard IEC 62933-5-2 (Safety requirements for grid-integrated electrochemical energy storage systems) regulates the electrical and operational safety of the storage facility itself — not the foundation geotechnics. It is important for the investor to know that:

IEC 62933 addresses batteries, the control system, and fire protection inside the container
Eurocode 7 and EN 1990 deal with the foundation and the load-bearing structure
Both areas overlap in the project documentation, but they are assessed separately and often by different specialists.

Concrete foundations (pad foundations, pillars, strip foundations) are created by excavation, reinforcement with steel armatura, and pouring cement concrete. Before loading, it is necessary to wait 7–28 days for curing. The load-bearing capacity reaches 20–100+ tonnes per point, but at the cost of significantly higher expenses and a longer time.

Fire separation distances — national regulations

Unlike Eurocodes, there is no harmonised European standard for separation distances between BESS containers. This area is governed by national fire regulations and, in practice, is assessed on an individual basis with the local fire authority or an authorised fire safety expert.

Practical impact for EPC contractors: Clearance distances affect the placement of containers on the site, and therefore also the placement of foundation points. We recommend addressing the fire safety concept before the geotechnical foundation design is finalised — changing the container layout after the ground screws have been installed is costly.

How BESS projects are addressed in key EU countries

Czech Republic Geotechnical design in accordance with CSN EN 1997. The fire safety of the BESS is assessed by an authorised fire safety engineering specialist as part of the planning permission documentation.

Germany: DIN EN 1997 as the national implementation of EC7. BESS installations above a certain capacity are subject to approval under the BImSchG (Federal Immission Control Act) and VDE requirements for electrical safety.

Austria: ÖNORM B 4435 complements Eurocode 7. The fire safety assessment of the BESS is handled by the local fire service authority (Landesfeuerwehrverband) depending on the size of the installation.

France NF EN 1997 as a national implementation. BESS above a certain capacity fall under the ICPE (Installations Classées pour la Protection de l’Environnement) regime with their own requirements for separation distances and safety.

Poland: PN-EN 1997 as a national standard. The growth of the BESS market in Poland is driven by combination with PV projects, with geotechnical design standardly in accordance with Eurocode 7.

In all countries, the following applies: the geotechnical foundation according to Eurocode 7 + EN 1990 is universal across the EU, whereas fire and operational approvals are always dealt with by local legislation and local authorities.

Checklist for a BESS project on ground screws in the EU

Specification sheet for the container with point loads from the manufacturer BESS
Site geotechnical investigation and determination of bearing capacity according to EN 1997
Static calculation of load combinations according to EN 1990 (incl. wind, and seismicity where applicable)
Design of load-bearing heads/profiles for transferring point loads into the screw
Fire safety concept and separation distances according to national regulations — to be resolved prior to finalising the layout
Telemetric installation record for each screw (torque × depth)
Geodetic verification of flatness within the container manufacturer's tolerance
CE certification of the screwing machine and documentation for the building authority

Frequently Asked Questions

Is there a unified European standard for the separation distances of BESS containers?
No. Clearance distances are governed by national fire regulations of individual EU countries, not by a harmonised European standard. They need to be addressed with the local fire authority or an authorised person.
How does geotechnical design for a BESS differ from that for a photovoltaic structure?
The BESS container transfers the load to several concentrated points with a higher unit load, whereas the PV mounting structure distributes the load over a larger number of lighter points area-wise. Eurocode 7 addresses both situations, but the design of the individual screw and the assessment of the group effect differ.
What role does IEC 62933 play in a BESS project?
IEC 62933-5-2 governs the electrical and operational safety of the storage system itself (batteries, control system, fire protection inside the container). It is not related to foundation geotechnics, which are covered by Eurocode 7 and EN 1990.
Is it necessary to recalculate the foundation structural analysis for each EU country?
National Annexes to the Eurocodes adjust partial factors and combination rules, therefore a structural calculation prepared for one country is not automatically valid in another. We recommend collaboration with a local chartered structural engineer.

Where to continue

How the installation of the foundation for BESS containers works in practice: Battery storage systems on ground screws

General overview of geotechnical design according to Eurocode 7: Eurocode 7 and ground screws