The most valuable market for stored electricity in Southeast Europe is not necessarily the one with the highest average power price. Returns depend on a battery’s business model and what it can earn after competition, costs, degradation and access to balancing services are taken into account. That can lead traders, banks and portfolio owners to favour different markets.
Storage earns revenue from price differences between hours and from system services. Average day-ahead prices alone therefore do not show the value of a stored megawatt-hour. The relevant comparison is revenue per usable MWh after market-access costs, grid charges, fees and degradation, as well as the depth of balancing opportunities.
Capacity figures show differing market scales. Hungary had 1,053.4 MW of grid-scale battery capacity listed at 1 October, while Romania had 1,162 MW and 2,312 MWh of storage capacity at the same date. Bulgaria had more than 6.2 GW of storage capacity and 19 GWh by the latest estimates. Its larger fleet offers scale and sophisticated storage operations, but also brings intense competition for arbitrage.
Romania combines a rapidly growing storage fleet with strong merchant and balancing opportunities. Its non-recourse precedent may make it attractive to banks. Hungary’s storage expansion is supported by market reform and a large solar base. In Serbia, the operating storage fleet remains smaller than in the other markets discussed, but stronger price volatility may offer wider scarcity margins because flexibility is scarcer. Standalone storage there carries more regulatory and financing uncertainty.
The ranking can change with the business model. A pure merchant trader may prefer a less saturated market, while a portfolio owner may favour Bulgaria, where storage can be combined with large solar assets and mature dispatch experience. Investors should model the same battery configuration in each market using identical technical assumptions before deciding where an asset is worth most. The comparison should account for competition, fees, degradation and balancing access, rather than relying on average spot prices or capacity totals.