Bulgarian manufacturer unveils 8.1 MWh battery energy storage system

Bulgaria-based storage manufacturer IPS has released a new utility-scale BESS with a rated capacity of 8.1 MWh and an integrated 4 MW inverter. The X-BESS 8 system is housed in a 20-foot container footprint equivalent and features liquid cooling.

“On the capex side, the compact, modular architecture allows for effortless customization and future-proof scaling while significantly reducing costs for balance of system (BOS), transportation, and installation,” said IPS CEO Alexander Rangelov. “On the opex side, easy maintenance and reliable operation over the full lifespan of the system is ensured via a distributed design of all critical components, with no single point of failure for the overall system.”

The new BESS uses 314 Ah lithium-iron-phosphate (LFP) battery cells and reportedly has a lifetime of 12,000 cycles. On the AC output side, it has a maximum output current of 2,890 A and a maximum output power of 4 MVA. It uses a liquid-cooled, three-level inverter topology that achieves 99.5% efficiency, according to the manufacturer.

The X-BESS 8 is designed in compliance with IEC 61000, IEC 62619, IEC 62477, EN 50549, UL 1741, and CE standards. Its operating temperature is between -40 C to 70 C. It features 12 operating modes, including grid support, black start, and operation in an isolated network.

“The system is delivered in segments – lightweight, sub-8-ton blocks that require no specialized heavy-lifting equipment for transport or installation,” the company said. “Each block is fully plug-and-play, with standardized mechanical and electrical interfaces to ensure rapid, low-complexity on-site integration.”

The EXERON X-BESS series is currently in production with 5 MWh and 6.5 MWh models.

IPS designs and manufactures in-house all system components except the LFP cells, including inverters, thermal management systems, battery modules, packs and BESS housing. Critically, all control software and embedded firmware is developed and maintained in strict alignment with EU cybersecurity frameworks. 

To address rapidly growing demand for energy storage solutions, IPS is set to open its next automated manufacturing facility in Sofia, Bulgaria, in June 2025. The plant will launch with a 1.5 GWh annual capacity, scaling to 3 GWh by the end of 2025.