Bulgaria led Southeast Europe’s battery-storage markets by capacity by late 2026, with more than 6.2 GW and 19 GWh, according to a late-2026 market assessment. It compares operating scale, financing precedents, policy backing and grid access, rather than simply ranking expected investment returns.
Operating capacity and financing
Bulgaria’s storage growth is supported by recovery-plan funding, merchant projects and a rapidly growing solar fleet. Romania combined operating capacity with a financing precedent: it had 1,162 MW and 2,312 MWh of battery storage as of 1 October, alongside non-recourse financing at Scornicesti and a Modernisation Fund support call worth 150 million euros.
Hungary had more than 1 GW of grid-scale battery capacity recorded in October, following strong commissioning in 2026. In Greece, the Larissa battery, at 330 MW / 790 MWh, and the HELLENiQ project, at 100 MW / 200 MWh, both entered service in October and established large operating references.
Policy backing and grid access
Serbia has around 2 GW of reported storage connection agreements, and SEEPEX now permits negative prices. Evening electricity scarcity can be severe, but the market still needs more operating standalone batteries and financing precedents, leaving a gap between connection interest and demonstrated operating capacity.
Croatia has an EU-level pledge for an additional 500 MW / 1,000 MWh of storage by 2028, although its operating fleet remains much smaller than those of the leading markets. The pledge reflects policy ambition, while the existing fleet remains a distinguishing feature of the market landscape.
Montenegro is moving toward a strategic-partner model around a 60 MW / 240 MWh reference project. North Macedonia has a state-backed battery-storage project valued at 98 million euros and sized at 100 MW / 400 MWh. Albania’s Erseke development combines 75 MWp of solar capacity with 40 MWh of storage. Montenegro, North Macedonia and Albania are earlier-stage markets but are described as strategically relevant.
The assessment says mature markets offer clearer rules but face more competition, while earlier-stage markets can offer wider spreads alongside greater regulatory and financing risk. An investor’s choice depends on whether it seeks merchant optionality, contracted cash flow or strategic first-mover exposure. The trade-off is between lower regulatory risk and more competition in mature markets, and wider spreads with greater risk in less mature ones.
