Romania’s curve provides the clearest warning against valuing generation or supply contracts against a single daily reference price.
OPCOM prices declined below €20/MWh before noon, reached zero in multiple fifteen-minute intervals and remained close to zero for several hours. After 17:00, the curve began rising rapidly, passing €150/MWh during the evening and reaching €310/MWh shortly before 21:00.
Romania can therefore experience renewable oversupply and an adequacy problem on the same delivery day. The country has added solar capacity quickly, including utility projects and a large prosumer fleet. That generation produces simultaneously and has limited ability to respond to price.
At the same time, one of the two 680 MW Cernavodă nuclear reactors is unavailable, while the remaining unit faces continuing cooling-water risk. Hydropower output has been weakened by record-low Danube flows and poor reservoir conditions. The country must therefore replace inexpensive solar with gas, coal, imports, storage or industrial demand reductions as soon as photovoltaic output declines.
Domestic demand was recently expected to reach approximately 7,300 MW, against available internal generation of only 4,000–4,300 MW during the tightest periods. This theoretical deficit is not present throughout every hour, but it shows why Romania’s evening market can move from zero to €300/MWh within the same day.
The immediate storage opportunity is unusually clear. A two-hour battery charging during Romania’s zero-priced block and discharging around the evening peak faces a gross theoretical spread approaching €300/MWh. Actual revenue is lower after round-trip losses, degradation, grid charges, imbalance exposure and market-access costs, but the available margin remains substantial.
That spread will not persist unchanged as storage capacity expands. Romania is approving additional batteries alongside solar and wind installations. Authorities recently prepared commercial approvals for 324 MW of new capacity, including 176 MW of storage and 148 MW of photovoltaic and wind generation, while a further 990 MW is moving through documentation and validation.
The near-term effect is additional flexibility. The longer-term result will be competition among batteries for the same low-price charging intervals and evening discharge window. Projects dependent solely on day-ahead arbitrage will eventually face revenue compression; balancing, ancillary services and congestion-related income will become increasingly important.
