How a battery earns in Portugal

Portugal's transmission grid is run by REN — Redes Energéticas Nacionais, and the day-ahead price is set on the Iberian market MIBEL via operator OMIE in a single price zone shared with Spain. Renewables now cover 68% of national demand (2025, the highest ever), yet the grid is a bottleneck — Portugal is among the eight EU countries whose networks can absorb under 10% of planned renewables, and roughly 200 GWh were curtailed in 2024. That mismatch is exactly what a battery monetises: over the last 30 days the day-ahead spread averaged €108/MWh, about 113% of the average price — the arbitrage base for charging cheap and discharging into the evening peak. Storage is backed by real support: the PRR “Flexibility & Storage” call awarded €99.75 million to ~500 MW of projects, with a further 750 MVA tender due. Standalone batteries connect under ERSE Directive 3/2025 restricted-access agreements and REN's February 2025 capacity-reservation rules, and can stack revenue in aFRR balancing as Portugal joins the European PICASSO platform.

€108/MWh

Day-ahead spread — 113% of the average price (30 days), the battery arbitrage base

68% of demand

Renewables share of Portuguese electricity in 2025 (37 TWh), the highest ever recorded

€99.75million

PRR “Flexibility & Storage” grants awarded to ~500 MW of battery projects