Bulgaria has expanded its energy storage capacity after renewable developer Sunterra RE completed the second phase of its storage expansion program. The deployment adds nearly 397 MW of combined battery capacity and 1.3 GWh across three new facilities. All three installations have been commissioned following completion of the project work.
New battery sites in Galabovo, Kaloyanovo and Karlovo
The newly commissioned battery systems are located in the municipalities of Galabovo, Kaloyanovo, and Karlovo. The facilities are designed to store surplus electricity generated from renewable sources and return it to the grid during periods of higher demand. This configuration is intended to improve overall system flexibility.
The two largest facilities are situated in Galabovo and Kaloyanovo, each with installed capacity of 150 MW. The Galabovo site provides 450 MWh of storage, while Kaloyanovo reaches 506 MWh. A third installation in Karlovo adds an additional 97 MW and 320 MWh.
Regulatory approvals and market participation
Before becoming operational, all three installations received full approvals from the relevant regulatory authorities. The approvals confirm compliance with technical, safety, and market operating standards. With this clearance, the facilities can participate fully in electricity market operations.
LFP technology, duration, efficiency and lifetime
The projects were financed through Sunterra RE’s own capital. The battery installations use lithium iron phosphate (LFP) technology. Each system is designed for energy storage for up to four hours, with efficiency rates of around 90%.
The expected operational lifespan for the installations is approximately 25 years. By storing excess renewable generation and releasing it during peak consumption periods, the new systems are expected to support grid balancing. The company also states that the projects will enhance market flexibility and help integrate higher volumes of renewable energy into the national power system.
