Battery developers in Southeast Europe face tougher debt tests as energy spreads compress and storage capacity grows, with lenders needing to assess balancing revenues separately from day-ahead arbitrage. According to project information on regional markets and North Macedonia’s planned Bitola battery, saturation is a distinct risk for these income streams.
Romania had 1,162 MW of storage by 1 October. Hungary’s storage capacity rose from 197 MW in January to more than 700 MW and 1,400 MWh by 18 August, while grid-scale capacity had passed 1 GW by October. These markets show the appeal of fast-response battery revenues, but ancillary-service demand may not grow in step with installed capacity.
Balancing and ancillary services can help distinguish projects capable of supporting debt from merchant projects that rely heavily on day-ahead arbitrage. However, ancillary-service markets can saturate faster than day-ahead trading. Batteries may qualify for frequency or balancing products, but clearing prices can fall sharply as competition increases.
Lenders must distinguish revenue a battery is technically able to earn from income it can sustain. Availability obligations, response times, state-of-charge management and penalties can reduce the capacity available for energy arbitrage. A bankable project therefore needs to show how operating requirements affect the revenues it can realise, as well as its technical eligibility for market products.
North Macedonia plans a 100 MW / 400 MWh battery in Bitola, where balancing capability is a project objective rather than an optional merchant-revenue opportunity. Valued at EUR 98 million, the project is being structured with sovereign-guaranteed and concessional finance. Its value is described as including reliability, curtailment reduction and system services, alongside trading margin.
A bankable Southeast European battery model should combine arbitrage, balancing and capacity-like income, applying independent haircuts to each revenue pool. The streams should not be stress-tested using the same correlation assumption. The strongest projects will demonstrate that they can service debt even if one source of revenue becomes crowded.
