Southeast Europe’s Battery Boom Faces a Reality Check on Execution and Revenues

The Southeast Europe BESS market outlook is entering a new phase. At Balkan Battery Day 2026, one message repeatedly surfaced during the panel discussion on the regional battery storage market: investor interest is no longer the primary challenge. Execution is.

Moderated by Nikos Sofianos, the discussion brought together senior executives and analysts from across the battery storage value chain, including Alastair Hammond of Rezolv Energy, Evangelos Gazis of Aurora Energy Research, Gabriel Nenov of Solarpro Holding and George Chronaios of Principia Energy.

Together, they painted a picture of a region moving rapidly from battery market optimism toward a more complex phase shaped by financing constraints, regulatory bottlenecks, merchant risk exposure and operational learning curves.

The Market Has Only Just Started Moving

Among the speakers, Alastair Hammond of Rezolv Energy delivered one of the clearest assessments of where Southeast Europe currently stands in the energy transition cycle.

While many markets present the region as an established renewable energy success story, Hammond argued that real momentum only emerged during the last five years following a prolonged period of inconsistent policy support and limited deployment activity.

That acceleration is now substantial. Rezolv Energy currently has more than 2.3 GW of solar and wind projects under development across Central and Eastern Europe, particularly in Romania and Bulgaria, reflecting the scale of investor interest entering the region.

Hammond also highlighted the growing role of bilateral power purchase agreements (PPAs) in enabling renewable and storage projects to move forward without direct government support. As merchant exposure increases, developers are relying more heavily on market-based revenue models rather than subsidy structures.

This transition signals a maturing market, but also introduces greater complexity and risk for battery developers.

Europe Still Faces a Massive Storage Gap

The discussion repeatedly returned to the scale of Europe’s storage challenge.

According to figures referenced during the panel, the European Union is targeting approximately 700 GWh of battery storage capacity by 2030, while currently installed capacity remains only a fraction of that requirement.

Battery storage is now widely recognised as essential for integrating growing volumes of renewable energy, yet transmission infrastructure, market design and supply chains are still struggling to evolve at the pace required.

Hammond pointed specifically to the future challenge of integrating large battery fleets into interconnected regional grids, particularly between Greece and Bulgaria, where substantial renewable and storage capacity is already being prepared.

The conclusion was clear: Europe’s energy transition is no longer constrained by ambition. It is constrained by execution capability.

Bulgaria Is Emerging as a Regional Leader

The panel highlighted Bulgaria as one of Southeast Europe’s fastest-evolving battery storage markets.

Unlike Greece, which relied heavily on auction frameworks and more complex regulatory procedures, Bulgaria’s growth has been accelerated through EU recovery funding mechanisms focused on CAPEX support.

According to Aurora Energy Research and Solarpro Holding, this has triggered significant deployment momentum, with multiple gigawatt-hours of battery projects already operational or under construction.

Solarpro Holding revealed that more than 40 battery projects are currently under development across several European markets, with expectations of reaching 4.5–5 GWh either operational or under construction by the end of the year.

Romania, meanwhile, was repeatedly identified as one of Europe’s most promising long-term battery markets, although permitting and regulatory processes continue to slow execution.

Battery Operations Are Far More Complex Than Solar

One of the most practical insights came from Gabriel Nenov of Solarpro Holding, who explained how fundamentally different battery assets are compared to traditional solar projects.

Unlike solar PV, which operates relatively passively, batteries require continuous optimisation, forecasting and active participation across multiple electricity markets.

Successful operations depend on sophisticated EMS and SCADA systems, electricity trading integration, operational analytics and ongoing optimisation across different revenue streams.

This is creating a new competitive advantage within the sector.

As several speakers noted, the real first-mover advantage in battery storage is not simply building projects first. It is learning how to optimise assets before market cannibalisation begins to erode profitability.

Cannibalisation May Reshape Battery Economics

Another important perspective came from Evangelos Gazis of Aurora Energy Research, who highlighted a challenge that many emerging battery markets will inevitably face.

In the early stages of deployment, batteries benefit from strong balancing spreads and attractive ancillary service revenues. However, as more storage enters the system, those same opportunities begin to compress.

According to Gazis, future profitability will increasingly depend on portfolio optimisation, hybrid renewable integration, multi-market participation, ancillary services and long-duration operational strategies.

Over time, batteries are likely to evolve from standalone arbitrage assets into integrated infrastructure tools supporting broader renewable portfolios and system stability.

This evolution may fundamentally reshape how battery projects are financed, operated and valued.

Financing and Bankability Remain Critical

Despite the sector’s momentum, financing remains one of its most significant constraints.

George Chronaios of Principia Energy stressed that battery projects must become bankable in order to scale. Revenue certainty remains essential for lenders, particularly as merchant risk exposure increases across the region.

Long-term tolling agreements, CFDs, structured hedging mechanisms and hybrid renewable portfolios are becoming increasingly important tools for improving project bankability and securing financing.

The discussion suggested that batteries may gradually become less attractive as purely speculative standalone investments and more valuable as part of diversified renewable portfolios capable of naturally hedging volatility and negative pricing exposure.

Europe’s Industrial Ambitions Face a Supply Chain Challenge

Toward the end of the discussion, Hammond raised another issue likely to shape the future of Europe’s storage sector: manufacturing capacity.

While Europe seeks to reduce dependency on imported clean energy technologies, speakers acknowledged that current European manufacturing capabilities remain insufficient for the scale of deployment required over the coming decade.

The region therefore faces a delicate balancing act between industrial policy, energy security and the urgent need to accelerate renewable and storage deployment.

From Ambition to Execution

The panel’s conclusion was clear.

Southeast Europe has become one of Europe’s most attractive battery investment regions. However, the next phase of growth will depend not on project announcements alone, but on the industry’s ability to execute, optimise and finance projects at unprecedented scale.

The battery market has moved beyond proving demand. The challenge now is delivering on it.