Bulgaria has started construction of a 300 MWh battery energy-storage facility at Tvarditsa. The project is the first stage of a wider programme valued at more than €350 million. The broader plan includes three battery projects with combined storage capacity of more than 2.3 GWh.
The Tvarditsa installation is being developed by Asarel-Trade and Power Profit using Tesla technology. The facility will use 80 Tesla Megapack 2XL units and 20 transformers rated at 4.4 MVA. It is designed to provide around five hours of discharge capability.
Storage expansion linked to changing intraday power balance
Battery investment has accelerated across Bulgaria as rising solar and wind capacity changes the country’s intraday power balance. New storage is expected to absorb surplus renewable electricity during high-output periods. It would then return electricity to the grid when generation declines or demand rises.
The programme is expected to reduce balancing requirements and limit some sharp wholesale-price swings associated with high renewable penetration. Once completed, the three-project battery programme is expected to provide more than 2,300 MWh of storage.
Additional flexibility investments and regional trading role
Bulgaria is also considering additional storage, pumped-storage hydro and generation investments as it modernises the electricity system. The aim is to create more flexibility for renewable projects. An emerging battery fleet could support Bulgaria’s role as an electricity-trading hub in Southeast Europe.
This would be particularly relevant during periods when solar output creates large daytime surpluses followed by steep evening ramps. The rollout also positions battery storage as a standalone component of Bulgaria’s electricity-market infrastructure.