Clean Horizon Storage Index, September 2026 (1/3): European takeaways

Writing this from Helsinki, where Clean Horizon's new Storage Index for September 2026 caught my attention, partly because Finland is in it too.

A few takeaways that stood out for me:

Iberia keeps setting records. A 2-hour battery in Portugal reached 722 k€/MW/year (+18.4% vs August), and Spain reached 562 k€/MW/year (+10.8%), both mainly driven by higher aFRR capacity prices.

Germany rose by 10% month-on-month across all durations, as wider day-ahead spreads followed higher evening prices.

France held steady at 440 k€/MW/year for a 2-hour system, with aFRR and FCR capacity making up 89% of revenues.

Romania was one of the strongest rebounds: 306 k€/MW/year for a 2-hour battery, +71.9% compared to August.

Here in Finland, revenues recovered to levels last seen at the beginning of the year, with the 1-hour day-ahead spread up 68%.

Not every market moved up. Lithuania (-30%) and Latvia (-29%) declined as mFRR and aFRR capacity prices dropped, although higher day-ahead spreads helped sustain revenue levels.

What I take from this: battery storage in Europe is not one market but many, each with its own drivers. The common thread is that flexibility is increasingly valued, whether through balancing services or price spreads.

Thank you to Clean Horizon for this clear monthly snapshot. Full details here: https://lnkd.in/e67JbTAv

Which of these markets do you follow most closely, and what surprised you this month?

#EnergyStorage #BESS #RenewableEnergy #EnergyTransition #Flexibility