Romania solar and storage: the last twelve months.

Executive summary

Midday power was cheap and evening power expensive, so storage added most of the value.

Prices are high and volatile. Romania's day-ahead market averaged 124.5 EUR/MWh between October 2025 and September 2026, 15% above calendar 2025. Of the eight bidding zones we compared, only Hungary was higher (127.1). Germany averaged 104.0 and Spain 73.3. Prices rose sharply from August 2026: September averaged 176.2 EUR/MWh and the first half of October 206. We do not use these months as a base case.

Solar keeps midday prices low. Metered solar output reached 3,395 MW at its peak and covered 38% of generation between 11:00 and 14:00 from April to August. Midday prices averaged 75.5 EUR/MWh, while the 18:00 to 22:00 window averaged 182.4. A fixed-tilt solar plant in Dobrogea captured 60% of the baseload price over the year and 40% in April, when 38% of its output fell in quarter-hours priced at zero or below.

Storage earns from the gap. The average daily spread between the 16 most and least expensive quarter-hours was 152 EUR/MWh. Romania's evening-to-midday gap (107 EUR/MWh) is among the widest in the region. Balancing capacity adds income, but that market is small: Transelectrica buys about 125 MW of frequency containment reserve (FCR) and about 175 MW of automatic frequency restoration reserve (aFRR) in each direction. Compared with the first half of 2025, aFRR capacity prices fell by 44% (up) and 73% (down), and the number of FCR providers nearly doubled in 2026.

There is no free grid capacity. Transelectrica shows no capacity available without reinforcement in any zone for 2028 to 2037. New capacity is allocated through annual auctions. Projects that already hold firm connection rights are therefore the scarce asset.

The hybrid case. For a 350 MWp solar plant with 350 MW / 1,400 MWh of storage in Dobrogea, dispatched every 15 minutes on actual prices, storage lifts annual net revenue from 39 M EUR (solar alone) to 132 M EUR, as a perfect-foresight ceiling. With conservative assumptions the project still returns 11.8% unlevered after tax, before any payment for the project rights.

For equipment suppliers, the numbers favour high-yield modules and longer-duration batteries. A bifacial TOPCon module yields 8.6% more energy than mono PERC on the same site, worth about 9.7 EUR per kWp each year at this year's solar prices. Extending storage from 2 to 4 hours earned about 38 EUR per added kWh a year (33 after a 15% haircut for imperfect forecasting), against our estimate of 120 to 140 EUR/kWh for turnkey 4-hour storage.