Sunterra RE Adds 1.3 GWh Storage to Bulgaria Solar

• Sunterra RE boosts Bulgarian solar with Phase 2 BESS: 1.3 GWh added across three parks, reaching nearly 397 MW/1.3 GWh—4-hour LFP storage with permits and 25-year design.

Bulgarian renewables firm Sunterra RE has commissioned Phase 2 of a battery energy storage project adding 1.3 GWh of capacity across three solar parks in Galabovo, Kaloyanovo and Karlovo. The installations bring total site storage to nearly 397 MW/1.3 GWh, with the batteries designed for up to four hours of storage, 90% efficiency and 25 years of operation.

The lithium iron phosphate (LFP) systems are rated at 150 MW/450 MWh in Galabovo, 150 MW/506 MWh in Kaloyanovo and 97 MW/320 MWh in Karlovo. Sunterra said it received operating permits confirming the projects meet technical, regulatory and safety requirements. The BESS was self-financed as part of its expansion strategy to store solar power and dispatch it during peak demand.

How does Sunterra RE’s Phase 2 BESS expansion boost Bulgaria’s peak power dispatch?

• Increases the amount of dispatchable electricity available during Bulgaria’s highest-demand periods by adding 1.3 GWh of storage capacity to the existing portfolio.
  
• Enables time-shifting: solar generation that occurs earlier in the day can be stored and released when evening and late-afternoon demand spikes.
  
• Supports “peak shaving” by reducing how much power plants must run at full output during the most expensive hours, helping system operators meet load with less reliance on ramping thermal units.
  
• Provides up to four hours of discharge per cycle, making the new batteries especially useful for covering multi-hour peak windows rather than only short-duration peaks.
• Improves effective grid flexibility through fast power response: BESS units can inject or absorb power quickly, helping balance supply and demand during sudden demand jumps or cloud-driven solar variability.
  
• Helps limit renewable curtailment by storing excess solar energy when generation exceeds immediate consumption, then dispatching it later during constrained peak periods.
  
• Adds operating leverage to the three connected solar sites (Galabovo, Kaloyanovo, Karlovo), meaning peak support can be distributed across multiple grid areas rather than concentrated at a single point.
  
• Enhances system adequacy by increasing the grid’s firm capacity contribution from renewables, particularly during hours when solar output naturally declines.
  
• Uses high round-trip efficiency (about 90%), which improves the usable energy delivered during peak dispatch compared with lower-efficiency storage options.
  
• Strengthens reliability and long-run planning: a long operational lifetime (around 25 years) turns the peak-dispatch capability into a durable resource rather than a short-term add-on.