Southeast European battery projects face tighter financing tests as energy spreads compress and storage capacity expands. Balancing revenues may support debt, but lenders need to assess their exposure to market saturation separately from day-ahead arbitrage. Project data show Romania had 1,162 MW of storage by 1 October.
Hungary’s storage capacity climbed from 197 MW in January to more than 700 MW and 1,400 MWh by 18 August. By October, the country’s grid-scale storage capacity had passed 1 GW. The figures illustrate the appeal of fast-response battery revenues, as well as the risk that demand for ancillary services may not grow in step with installed capacity.
Balancing and ancillary services can help distinguish projects able to support debt from merchant projects reliant on day-ahead arbitrage and equity. However, ancillary-service markets can saturate faster than day-ahead trading. A battery may qualify for frequency or balancing products, but clearing prices can fall sharply as more batteries compete.
Lenders therefore need to separate revenue a project is technically able to earn from income it can sustain. Availability obligations, response times, state-of-charge management and penalties can also reduce the capacity available for energy arbitrage.
Bitola project includes balancing in its purpose
North Macedonia plans a 100 MW / 400 MWh battery in Bitola, where balancing capability is an objective of the project rather than an optional merchant-revenue opportunity. The project is valued at EUR 98 million and is being structured with sovereign-guaranteed and concessional finance.
The project’s value is described as including reliability, curtailment reduction and system services, alongside trading margin. Its planned financing and balancing role contrast with a merchant approach based on trading revenues alone.
A bankable Southeast European battery model should combine arbitrage, balancing and capacity-like income, applying independent haircuts to each revenue stream. They should not all be stress-tested using the same correlation assumption. The strongest projects will show they can service debt even if one revenue pool becomes crowded.