Romania's 918MWh Battery Bet: CATL Signs Europe's Largest CEE Storage Project as the Region's Grid-Scale Build-Out Accelerates

Introduction

A single project announced in the second half of September 2026 captures almost everything that has changed in the European battery storage market over the past eighteen months. In Bacău County, in eastern Romania, a special purpose vehicle called Borzești Energy Storage — jointly owned by RNV Infrastructure, part of the Romanian Renovatio Group, and Greenvolt Power of Portugal — is building a 918 megawatt-hour battery energy storage system. Renovatio's engineering, procurement and construction arm, Renovatio Solar, holds the full EPC contract. CATL, the Chinese cell maker that holds roughly 38 percent of the global battery market, supplies the battery technology.

The numbers are large but the timing is the real story. Romania is not an outlier; it is the sharpest example of what is happening across Central and Eastern Europe, where grid-scale storage has moved from pilot projects to a genuine build-out in barely two years. Within a single week in late September 2026, the region's developers announced a 918MWh project in Romania, a completed 120MWh plant in Alba County, a 50MWh order from solar heavyweight LONGi, a €19 million financing for a first Romanian battery asset, a 165MWh retrofit in Bulgaria, and a 40MWh hybrid in Hungary. That is not a market waking up. It is a market that has already woken up and is now compounding.

Our Battery Tech coverage has tracked the laboratory end of this sector closely — the solid-state and sodium-ion chemistry races that will eventually determine the energy density of the cells themselves. What the Borzești announcement illustrates is the other half of the story: the deployment layer, where cell chemistry becomes a procurement decision and a financing problem, and where the winners are increasingly decided by construction capability rather than by watt-hours per kilogram.

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A landmark deal with an unusual structure

The Borzești project is notable less for its capacity than for the way responsibility has been allocated across three continents. Greenvolt Power and RNV Infrastructure carry the ownership and the capital. Renovatio Solar carries engineering, procurement, construction and commissioning under a single integrated contract, with an estimated execution period of twelve months. CATL supplies the technology and, implicitly, a tier-one supply chain that gives the project credibility with lenders.

Horatiu Regneala, CEO of Renovatio Solar, framed the appointment in explicitly capability terms. In his telling, being selected as full EPC contractor for a BESS of this scale demonstrates that the Romanian market has developed the engineering, procurement and construction capabilities required to deliver a category of project that until now had rarely been seen in the country. It is a domestic-maturation argument as much as a commercial one: the assumption embedded in the deal is that the region can now build grid-scale storage locally rather than importing the whole delivery chain.

João Manso Neto, CEO of Greenvolt Group, placed Borzești within a wider platform. The Portuguese company describes a 5 GW portfolio of energy storage projects, with Hungary and Poland as the anchor markets. Greenvolt inaugurated a 288.6MWh BESS in Hungary in June 2026 and secured a financing package in late August for two Polish BESS projects with a combined 1.6GWh. Borzești is the next point on a curve, not an isolated bet.

The operating logic is the same one that has driven the entire global storage build-out. The battery stores surplus electricity generated when solar output exceeds local demand, discharges it into the evening peak, and provides fast frequency response when the grid needs it. Reports on the project also emphasise a second benefit that is increasingly the deciding factor in CEE markets: enabling the integration of several hundred megawatts of renewable capacity without a proportional amount of new grid investment, and reducing reliance on imported energy.

The CEE quarter in review

The Borzești deal landed alongside a dense cluster of other announcements, and reading them together gives a clearer picture of the regional market than any single number does.

Romania is the centre of gravity. Eurowind Energy Romania, through vehicle Teiuș Solar SRL, completed and commissioned a 120MWh BESS in Teiuș, Alba County — a €21 million (about US$24 million) investment that began construction in March 2026. Enexus, a developer and EPC firm, ordered 50MWh of storage from LONGi for two solar-plus-storage projects in Dâmbovița County, in 15MWh and 35MWh blocks. It is the companies' first storage collaboration, notable because LONGi is a solar PV manufacturer that only recently entered the BESS space at all, through the acquisition of system integrator PotisEdge. MetaWealth, a real estate investment platform, closed a €19 million financing structure for its first BESS, a 50MW/100MWh project, assembled from €10 million in debt from CEC bank, €5.5 million from the founding Topolinski family and €3.5 million from its securitisation and bond platform.

The supply chain is diversifying in both directions. LONGi's entry on the integrator side and CATL's dominance on the cell side are two ends of the same trend. Buyers in the region are no longer limited to a handful of Western integrators, and the pricing power that accompanied that narrow supplier set a year or two ago has visibly weakened.

Financing structures are becoming routine. MetaWealth's three-part stack is unremarkable only because it is ordinary. A mixed bank-debt, sponsor-equity and capital-markets package is what a maturing asset class looks like when banks are willing to lend against contracted grid services. In Bulgaria, MetaWealth's peer Renalfa IPP went a different route, repowering and hybridising its Devnya PV plant — increasing capacity from 5MWp to 65MWp and adding 60MW/165MWh of storage, with Solarpro as EPC contractor. MOL Group completed a 37.4MWp solar and 20MW/40MWh BESS project in Hungary at Algyő, benefiting from funds under Hungary's EU-backed capex grant scheme.

One speaker at the Energy Storage Summit Central and Eastern Europe event put the regional position bluntly: Bulgaria is now the most battery-heavy electricity market in the world, measured by storage as a share of electricity. That is a striking claim, and it depends on the denominator, but it captures the speed of the transition. The summit takes place on 6–7 October 2026 in Warsaw, Poland.

Why the deployment layer matters more than the chemistry race

The pattern across all of these projects is that the binding constraint has moved. Solid-state and sodium-ion developments generate the headlines because they promise better energy density or lower raw-material cost, and both matter enormously over a ten-year horizon. But none of those chemistries can be deployed at scale without EPC contractors who know how to build a fenced, fire-protected, grid-connected battery farm; without lenders who understand the revenue stack; and without a regulatory framework that lets a storage asset earn more than the energy it happens to be holding at any given moment.

Borzești is best read as evidence that CEE has cleared that deployment threshold. A 918MWh system is not a pilot. At a plausible two-to-four hour duration, it implies something in the region of 230MW to 460MW of power capacity, which is the scale at which a battery installation becomes a meaningful participant in regional frequency and balancing markets rather than a curiosity.

There is a strategic dimension too, and CATL's role makes it unavoidable. The Renewables-First geopolitical logic that supplied most of Europe's storage in 2022 and 2023 — cells from Asia, containers assembled in Europe, projects financed by Western capital — has been complicated by tariffs, foreign-entity-of-concern rules, and restrictions on imported power equipment. That has pushed US integrators toward domestic manufacturing while also raising costs and, in at least one documented case this month, contributing to a US storage integrator cutting its full-year revenue guidance by roughly US$600 million and widening its expected adjusted EBITDA loss to about US$200 million from roughly US$10 million. Supply chain localisation is not a free policy; someone absorbs the cost.

Romania sits on the comfortable side of that trade-off. It has cheap hydro, substantial solar build-out, an EU framework, and now the financing to match. Borzești is the bet that it can also keep the engineering local.

Conclusion

The 918MWh Borzești announcement is worth more than its headline number, because it demonstrates that grid-scale storage in Central and Eastern Europe has acquired the three things that historically separate demonstration projects from an industry: a tier-one supply chain, a domestic EPC sector willing to sign a single integrated contract, and structured financing. Romania, Bulgaria, Hungary and Poland are now building storage at a pace that would have been implausible three years ago.

For buyers and investors, the near-term consequence is a more competitive procurement environment and, over time, downward pressure on installed storage costs as regional supply chains fill in. For grid operators, it means the balancing problem associated with large solar build-outs in the region finally has a physical answer. And for the technology story, it is a reminder that the solid-state and sodium-ion races will be decided less by who builds the best cell in a laboratory than by who can build the cheapest enclosure, on schedule, and connect it to a grid that will pay for the service.

Borzești is due to be completed within twelve months. It will be worth watching whether the 500MWh of other CEE projects announced in the same week follow the same path — and whether Europe's industrial policy treats the EPC layer as something to be built locally, or something to be imported.

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References

• CATL to supply 918MWh Romania BESS, another 500MWh of projects progress elsewhere in CEE — Energy-Storage.News, Cameron Murray, 23 September 2026.
• Renovatio, Greenvolt to build battery system of over 900 MWh in Romania — Balkan Green Energy News, Vladimir Berbatović, 21 September 2026.
• Renovatio Solar to Build a 918-MWh BESS for RNV Infrastructure and Greenvolt Power — Energy Industry Review, 21 September 2026.
• Fluence cuts 2026 revenue & EBITDA guidance as US production delays bite — Energy-Storage.News, Andy Colthorpe, 17 September 2026.
• Our related coverage — news.jualin.id Battery Tech.