Battery storage is expanding rapidly across Southeast Europe, with Hungary’s observable capacity set to exceed 1 GW later in 2026. The growing number of batteries trading is narrowing the volatility-driven opportunity that attracted investors, as increased participation can reduce price differences. Conservative long-term forecasts are therefore essential.
In Bulgaria, the latest estimate put storage capacity at more than 6.2 GW of power and 19 GWh of energy. Romania’s installed 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 grew from 197 MW in January to 778 MW by July 2026, then continued to more than 1 GW later in the year.
Early investors can earn scarcity rents that later projects may find difficult to reproduce. Capitalising early returns across the full operating life of each new battery risks assuming that competitors will not respond. A 15-year valuation based on today’s highest spreads makes that assumption even as additional capacity changes market conditions.
A stronger valuation model treats storage penetration as an endogenous variable, accounting for how projected market entry affects expected returns. With capacity growth, ordinary arbitrage margins can compress and balancing markets can become more competitive. Current spreads should not automatically be assumed to persist throughout a battery’s operating life.
As storage markets mature, value increasingly depends on location, duration, contract structure and portfolio integration. Batteries behind network constraints or able to access higher-value services can still outperform, making an asset’s position and revenue options more important to its investment case than volatility alone. The storage thesis remains intact, but the sector is expected to shift from a simple volatility trade toward 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.