Athens, Greece – March 5, 2026 – In a major step toward bolstering energy storage across Southeast Europe, Greece's leading power utility Public Power Corporation (PPC Group) and industrial powerhouse METLEN Energy & Metals (formerly Mytilineos) have signed a joint venture agreement (JVA) to develop, construct, and operate large-scale battery energy storage system (BESS) projects.
The partnership establishes a new equally owned company, with each partner holding a 50% stake. The venture focuses on a portfolio of BESS projects totaling up to 1,500 MW in power capacity and 3,000 MWh (3 GWh) in energy storage. This makes it one of the most ambitious storage platforms in the region, particularly in Romania, Bulgaria, and Italy.
Under the agreement, the partners aim to fast-track implementation, with approximately 1,000 MW(two-thirds of the total) expected to break ground and move toward construction within the next 12 months—an aggressive timeline that underscores the urgency of addressing grid flexibility needs amid rapid renewable energy growth.
The projects will primarily deploy two-hour duration, liquid-cooled lithium iron phosphate (LFP) battery systems, a technology widely favored for its safety, longevity, and cost-effectiveness in grid-scale applications. These systems are designed to store excess renewable energy from solar and wind sources and release it during peak demand or low generation periods, helping to reduce curtailment, stabilize grids, and capture revenue from energy arbitrage, frequency regulation, and ancillary services.
PPC Group, Greece's dominant electricity provider with extensive experience in power generation, distribution, and grid operations across the Balkans, will leverage its regional presence, regulatory expertise, and project development capabilities. METLEN, a vertically integrated leader in EPC (engineering, procurement, and construction), renewable project execution, and industrial metals, will bring its proven track record in delivering large infrastructure projects on time and at scale.
The collaboration builds on prior successes between the two companies, including a 2024 agreement for a multi-gigawatt solar pipeline in the same markets (Italy, Romania, Bulgaria, and Croatia). Analysts view this storage push as a natural extension, creating synergies between variable renewables and dispatchable flexibility solutions.
Southeast Europe is experiencing explosive growth in wind and solar installations, but legacy grids often lack the flexibility to integrate high shares of intermittent power. Large-scale BESS platforms like this one are seen as critical enablers for achieving EU decarbonization targets while maintaining reliability and minimizing curtailment losses.
For PPC, the deal aligns with its broader strategy—outlined at its 2025 Capital Markets Day—to expand beyond Greece and build a diversified portfolio targeting 13 GW of renewables by 2027, with storage playing a key role in monetizing flexibility. METLEN, meanwhile, continues to deepen its footprint in attractive European markets, including Italy, where predictable revenue streams from capacity and ancillary markets make BESS particularly compelling (though only a small portion—around 50 MWh—of the initial pipeline is slated for Italy).
Industry observers describe the partnership as a "perfect complement": PPC's operational and grid insight paired with METLEN's construction prowess positions the JV as a frontrunner in the shift toward utility-scale, platformized storage development in the region.
As Europe accelerates its transition to clean energy, this Greek-led initiative highlights how cross-border collaborations can deliver the infrastructure needed to support a more resilient, renewable-powered future.