Battery storage is expanding rapidly across Southeast Europe, with Hungary’s observable capacity expected to exceed 1 GW later in 2026. The growth is narrowing the volatility-driven trading opportunity that drew investors to the market. As more batteries trade, price differences can shrink, making conservative long-term forecasts essential.
Bulgaria’s latest estimate put storage at more than 6.2 GW of power and 19 GWh of energy. In Romania, installed battery storage capacity rose from 494 MW at the start of 2026 to 1,162 MW by October, an increase of about 668 MW. Hungary’s observable capacity climbed from 197 MW in January to 778 MW by July 2026, then continued rising to above 1 GW later in the year.
Capacity growth and battery valuations
Early investors can earn scarcity rents that later projects may find difficult to replicate. Applying those early returns across the full operating life of every new battery risks assuming that competitors will not respond. A 15-year valuation based on today’s highest spreads effectively makes that assumption, even as new capacity changes market conditions.
A stronger valuation model treats storage penetration as an endogenous variable, factoring projected market entry into expected returns. As capacity grows, ordinary arbitrage margins compress and balancing markets become more competitive. Current spreads should therefore not automatically be assumed to persist throughout a battery’s operating life.
As storage markets mature, value shifts toward location, duration, contract structure and portfolio integration. Batteries behind network constraints, or those with access to higher-value services, can still outperform. The investment case increasingly depends on an asset’s position and revenue options rather than volatility alone.
The storage thesis remains intact, but the sector is expected to evolve from a simple volatility trade into an infrastructure-and-optimisation business. The most successful batteries will remain useful even after their deployment helps reduce the price volatility that first attracted investment.