Portugal has introduced new technical regulations for large-scale battery energy storage systems (BESS), requiring advanced grid-forming capabilities and synthetic inertia to strengthen electricity grid stability and security. The new ministerial order, signed by Jean Paulo Gil Barroca, Secretary of State for Energy, came into effect on October 23, 2026. The regulations establish technical requirements for battery storage projects connecting to the country’s national electricity transmission network.
Under the new framework, battery energy storage installations with a capacity of 45 MW or above, as well as facilities directly connected to the primary transmission grid, must incorporate grid-forming capabilities and synthetic inertia. These technologies are designed to help battery systems support the electricity network by maintaining stable voltage and frequency during fluctuations in power supply and demand.
The introduction of these requirements comes as Portugal continues to increase the share of renewable energy in its electricity mix. Solar and wind power generation can vary depending on weather conditions, creating challenges for grid operators in maintaining a continuous and reliable electricity supply. Battery storage systems are expected to play an important role in balancing these variations and supporting the integration of additional renewable energy capacity.
The regulations also introduce operational requirements for smaller battery installations. Battery energy storage plants with a rated capacity of 500 kW or higher must automatically switch from charging to discharging whenever grid frequency falls. This requirement is intended to enable storage facilities to respond quickly to changes in grid conditions and provide additional electricity when the system experiences a supply imbalance.
Portugal’s new technical framework also places the country ahead of upcoming European Union developments concerning generator connection requirements. The national regulations are expected to be aligned with broader European grid connection standards as the EU updates its technical framework for electricity generation and storage facilities.
The requirements will primarily apply to new connection applications submitted after the regulations came into force. Existing operational battery storage installations will generally remain exempt. However, facilities undergoing substantial modernization, capacity expansion or major equipment replacement may become subject to the updated technical requirements.
The regulatory changes come at a time when Portugal is preparing to significantly expand its battery storage capacity. According to data from the Portuguese renewable energy association APREN, the country’s operational battery storage fleet currently stands at approximately 20 MW. This remains relatively small compared with the anticipated growth in electricity storage demand as renewable energy deployment increases.
Government funding programmes and recent financial allocations for several battery storage projects are expected to support the expansion of the country’s storage infrastructure. These initiatives are aimed at improving flexibility in the electricity system, managing renewable energy generation and strengthening energy security.
By introducing advanced technical requirements at an early stage of market development, Portugal aims to ensure that future battery storage installations contribute directly to grid stability. The regulations are also expected to establish clearer technical standards for developers and investors planning large-scale storage projects.
As renewable energy capacity continues to grow, battery storage is expected to become increasingly important in maintaining electricity supply reliability. Portugal’s new framework represents a regulatory step towards building a more flexible, resilient and renewable energy-based power system.
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