Poland and Italy leading Europe. Clean Horizon report reveals massive profits from energy storage

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Poland is currently the most attractive market for investors in large‑scale energy storage in Europe — according to the latest edition of the prestigious index published by consulting firm Clean Horizon. Italy and the Iberian Peninsula also made it to the podium. However, the analysis based on data from May 2026 reveals the first signs of saturation in some markets.

Poland at the top of Europe’s profit ranking

The updated Clean Horizon Storage Index brings excellent news for entities developing battery projects in Poland. Estimates show that a two‑hour energy storage system operating in Poland can generate an annual revenue exceeding EUR 800,000 (approx. USD 910,000) per 1 MW of power capacity.

What drives such a spectacular result? Clean Horizon analysts point directly to the market for ancillary services — specifically the very high prices of aFRR (automatic frequency restoration reserve). In May 2026, the average capacity price for aFRR in Poland exceeded EUR 120/MW/h.

Italy and the Iberian Peninsula surge upward

Right behind Poland are Italy, offering excellent conditions for four‑hour systems:

  • In northern Italy, the estimated annual revenue reached EUR 654,000/MW.
  • In the south, the figure stood at EUR 640,000/MW.

In Italy, however, the revenue structure looked different than in Poland — up to 80% of earnings in both regions came from the mFRR (manual frequency restoration reserve) market.

Investors on the Iberian Peninsula also have reasons to be pleased. In Spain, estimated revenues for two‑hour batteries increased by 5.5% month‑to‑month (driven by a 21% jump in aFRR prices and greater volatility in the day‑ahead market). Meanwhile, Portugal — debuting in the ranking — recorded a massive 43% surge in revenues, fueled by higher wholesale market spreads and stronger valuations of ancillary services.

The situation in other markets is as follows:

  • Germany maintains a strong position thanks to an effective combination of price arbitrage and ancillary services.
  • France saw a 17% decline in revenues due to lower aFRR and mFRR prices, though the market remains attractive for two‑hour systems.
  • Baltic countries had an excellent month — Latvia and Lithuania nearly doubled their April results, reaching EUR 338,000/MW and EUR 326,000/MW respectively. Estonia performed the weakest with EUR 175,000/MW.

New methodology captures the cannibalization effect

Clean Horizon has thoroughly revised the methodology of its index to better reflect market realities. The previous model assumed an idealized scenario in which every battery always captured the most profitable market window. The new model is based on average installed capacity and incorporates:

  • Direct competition between storage systems
  • Total volume of ancillary and system service markets in each country
  • Battery optimization in 15‑minute intervals using the COSMOS platform

Thanks to this, the index has captured early signs of market saturation for the first time. This phenomenon is clearly visible in Denmark (price zone DK1), where the growing number of operating storage systems has intensified competition and led to declining revenues from aFRR and mFRR markets. Clean Horizon describes this as revenue cannibalization — a mechanism that investors on all rapidly growing markets, including Poland, will need to defend against in the long term.

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