300 MWh Tvarditsa battery project starts construction
Bulgaria has started construction of a 300 MWh battery energy-storage facility at Tvarditsa, marking the first stage of a wider investment programme valued at more than €350 million. The project is part of a broader rollout aimed at adding utility-scale storage capacity.
The Tvarditsa installation is being developed by Asarel-Trade and Power Profit using Tesla technology. The system will include 80 Tesla Megapack 2XL units and 20 transformers rated at 4.4 MVA. It is designed to provide around five hours of discharge capability.
Three-project programme targets over 2.3 GWh of storage
The wider programme covers three battery projects with combined storage capacity of more than 2.3 GWh. Once completed, the three-project portfolio is expected to deliver more than 2,300 MWh of storage.
The expansion is linked to changes in Bulgaria’s intraday power balance as solar and wind capacity increase. New storage is expected to absorb surplus renewable electricity during high-output periods and return it to the grid when production declines or demand rises. The additional flexibility is also expected to reduce balancing requirements and limit some wholesale-price swings associated with high renewable penetration.
Storage plans alongside pumped hydro and generation upgrades
Bulgaria is also considering additional investments beyond batteries, including pumped-storage hydro and generation projects. These measures are intended to modernise the electricity system and create more flexibility for renewable deployment.
An emerging battery fleet could further support Bulgaria’s role as an electricity-trading hub in Southeast Europe. This would be most relevant during periods when solar output creates large daytime surpluses followed by steep evening ramps.
