How a battery earns in Bulgaria

Bulgaria's day-ahead price is set on the Independent Bulgarian Energy Exchange (IBEX), a full member of the EU's Single Day-ahead Coupling (SDAC), while the grid is run by ESO EAD, the transmission system operator managing over 15,000 km of lines and 297 substations. With solar past 6.5 GW in early 2026, midday prices now regularly plunge into negative territory — and that volatility is exactly what a battery monetises: the last 30 days show a day-ahead spread of €137/MWh, equal to 129% of the average price, the raw arbitrage a storage asset can capture by charging cheap at midday and discharging into the evening peak. The state supports the build-out through the EU-funded RESTORE 2 scheme (grants up to 50% of cost, capped near €79,000/MWh), and batteries can stack extra revenue in ESO's balancing markets — FCR, aFRR and mFRR — on top of arbitrage. Regulator EWRC requires a BGN 50,000 (€28,400) × MWh guarantee before grid connection, and assets above 10 MW connect at the ESO transmission level.

€137/MWh

day-ahead spread — 129% of the average price (30 days), the battery arbitrage base

3.3GW

storage online (ENTSO-E, May 2026), ~8.6 GWh, heading to 5 GW by end-2026

€79,000/MWh

RESTORE 2 grant cap (up to 50% of cost), EU Recovery-Plan funded