Portugal has introduced new grid connection rules for battery storage systems
It has specified grid-forming capability and synthetic inertia requirements for specified storage installations
The regulation aims to improve grid stability and electricity supply security as energy storage deployment increases
Portugal has introduced new grid connection rules that now mandate grid-forming capability and synthetic inertia for battery energy storage systems (BESS). The regulation took effect on October 23, 2026.
The requirements are set out in Order No. 464-A/2026/1 published in the country’s official gazette last week. These apply to new grid connection applications submitted from the date it came into force.
Under the regulation, grid-forming and synthetic inertia requirements apply to battery storage installations connected to the transmission grid. These include installations with a maximum power capacity of at least 45 MW or a grid connection voltage of 110 kV or higher, regardless of capacity.
Grid-forming technology enables battery systems to help regulate grid voltage and frequency, particularly during disturbances, while synthetic inertia helps limit frequency deviations and supports the stability of the electricity system.
All systems will need to automatically switch from charging to discharging when grid frequency falls below a predefined threshold of 49.2 Hz.
The regulation also sets out technical requirements for storage installations of 1 MW or higher to provide other grid services, including frequency and voltage control.
Portugal said the rules are intended to strengthen electricity system security and reliability as storage deployment expands.
The country is introducing these technical requirements for battery storage ahead of a planned revision of the EU’s Requirements for Generators (RfG) regulation. The rules will need to be aligned with the revised EU framework once it is published.
