New Battery Energy Storage System will enable ENGIE to provide flexible energy services

The pilot project for the construction of the ENGIE Group’s Battery Energy Storage System (BESS)  in Velka Ida was completed and started its operation earlier this year. BESS with capacity of  1.25 MW will provide support service for Transmission System Operator (FCR: +/- Frequency Containment Reserve GRID) and ENGIE Balance Group. The project is part of ENGIE’s strategy focused on providing comprehensive energy services using renewable energy sources.  


“The project for the construction and operation of the first ENGIE BESS in Slovakia is a significant milestone for our company. ENGIE is one of the European leaders of energy transition. And in line with our transition strategy, ENGIE in Slovakia transformed ourselves from a heating supplier to a provider of comprehensive energy services with a focus on decarbonization,” explains Milan Pavle, Key Account Manager at ENGIE Group.

The construction of BESS is part of complex energy solution of the Group. ENGIE no longer focuses only on energy generation and distribution. Group is adapting to ever-changing market demand and offer new solutions with a focus on flexibility and aggregation. ENGIE wants to get closer to its customers, who are also gradually becoming prosumers, and respond flexibly to their current needs.

BESS, as part of a comprehensive energy system, is integrated into the ENGIE Balance Group. Through new business models, it offers clients assistance and support in their energy solutions, regardless of business location.


ENGIE started the construction of BESS, which lasted 9 months, in April 2023. At the end of last year, the construction was completed and started its operation on the 1st January 2024.

Technical details of the new ENGIE BESS: 

  • Installed capacity: 1.25 MW
  • Battery operating life cycle: 6 000 cycles (approx. 10 years)
  • Management: ENGIE Balance Group / Central Dispatching 24/7 ENGIE Slovakia
  • Certifications that meets the complex standards of TSO (Slovak Electricity Distribution Network) for all business models.

Project BESS is installed and operated in direct output to The Transformation Station 110 kV in Velka Ida, which is owned and operated by ENGIE. Project BESS is located in the Velka Ida Industrial Park, where ENGIE provides electricity distribution.

Purpose and future plans

BESS was designed and should serve several purposes. The first is the providing FCR support services to Transmission System Operator. The FCR (Frequency Control Reserve) is the primary level of frequency control in the network with activation within 30 seconds.

“BESS also provides supported services to ENGIE Balance Group, develops renewable sources with fluctuating electricity production and provides inbalance management to our customers. With new BESS we can now offer our clients energy flexibility as a service,” explains Martin Zigo, Director of Energy Division at ENGIE Group.   

The ENGIE Group is already planning to build similar projects in other locations. “In addition to the construction itself, we want to offer energy flexibility as a service for prosumers and inbalance management for customers outside of our Balance Group,” concludes Martin Zigo.