ESNL is committed to future-proof European regulatory standards for energy storage

Energy Storage NL has called on the European Commission to adopt proportional and technically feasible connection rules for energy storage when revising the Requirements for Generators (RfG 2.0) grid code. The current RfG, dated 2016, was drafted for electricity generation units and does not yet include a separate European connection framework for energy storage systems, such as batteries. With RfG 2.0, these systems are explicitly brought within the scope of the grid code. ESNL welcomes this development, provided that the new requirements are based on demonstrable system needs and do not unnecessarily hinder investments in storage.

The new grid code will largely determine the technical requirements that will apply in the future to large-scale battery systems connected to the power grid. Clear and future-proof connection rules are needed to enable energy storage to contribute fully to a reliable and affordable energy system. Storage systems can quickly provide flexibility, balance supply and demand, and support the stability of the power grid. European regulations must leverage these qualities and prevent unnecessary technical or administrative requirements from undermining the business case and hindering investments in storage.

Proportional requirements for batteries

A key point of concern is the proposed introduction of requirements for grid-forming and synthetic inertia. With these capabilities, batteries can contribute to the stability and resilience of the electric power system. However, the necessary technology and market conditions are still very much under development. ESNL therefore advocates for a phased and needs-based implementation: a grid operator must transparently substantiate the system requirement in advance, specify the requested performance in a technically feasible manner, and offer appropriate compensation in return.

In this regard, the regulations must take into account the technical limitations of energy storage. A battery’s suitability for synthetic inertia, frequency support, and other forms of power response depends, among other things, on its state of charge, available energy, charging and discharging capacity, required response time, and necessary recovery time. ESNL therefore advocates for transparent calculation methods and clear limits on additional energy obligations. Without these safeguards, the requirements could lead to larger and more expensive systems, reduced operational flexibility, and a weaker business case, without any demonstrable system value to justify them.

Requirements for conventional generation units should not be applied directly to energy storage. A storage system can both draw and feed back electricity and switch quickly between these two operating modes. ESNL therefore advocates for a separate, coherent assessment of charging and discharging, so that the technical requirements are aligned and do not result in duplicate, conflicting, or technically unfeasible obligations.

Finally, ESNL calls for a clear definition of the term ‘significant modification’ as it applies to battery systems. Replacing or expanding battery modules on the DC side should not automatically lead to a complete reassessment of the grid connection. The inverter and the control system on the AC side are the primary determinants of the electrical behavior at the connection point. A new assessment is only appropriate when a modification demonstrably affects the system’s capacity or technical performance. This ensures that repairs, expansions, and lifespan extensions of properly functioning systems remain possible without unnecessary administrative burdens.

Practical rules strengthen storage

With practical and proportionate regulations, RfG 2.0 can better leverage the flexibility, speed, and controllability of energy storage. To achieve this, a transparent justification of technical requirements and appropriate compensation for additional performance are essential prerequisites. In this way, energy storage contributes cost-effectively to a reliable, affordable, and independent European energy system.

Following the consultation, the European Commission will incorporate the submitted comments into the proposal. Once the amended network code has been adopted, the requirements will be further elaborated at the national level. ESNL continues to actively monitor European decision-making and national implementation, contributing knowledge and practical experience from the network. In this way, ESNL advocates for regulations that support investments in energy storage and contribute to a reliable and future-proof electricity system.

Read ESNL's full consultation response