Power prices in Hungary, Bulgaria and Romania cleared close to €300/MWh on 4 November, remaining above western European levels despite expanding renewable capacity. Constrained firm generation and transmission, alongside scarce flexibility during peak demand hours, contributed to the premium.
Renewables do not always match demand when the system needs them most. Solar output is concentrated around midday and falls before the evening peak, while wind generation can swing by several gigawatts from one day to the next. Hydro availability has also been weak in several Balkan power systems.
Romania has been operating without both Cernavodă reactors because of low water levels on the Danube. In Bulgaria, one Kozloduy unit is out for scheduled maintenance until the end of November. When those outages coincide with weak hydro availability, Southeast Europe needs more imports, while Hungary is also structurally dependent on imported power.
That makes cross-border capacity increasingly important alongside generation capacity. The European Union Agency for the Cooperation of Energy Regulators (ACER) reported widening price differences between bidding zones in its 2026 market-integration review. EU congestion-management costs reached €5.4 billion in 2025, up from €4.3 billion in 2024.
ACER argues that increasing cross-zonal capacity, intraday trading and balancing integration is necessary as renewable penetration grows. The Southeast European premium illustrates the consequences of market integration improvements lagging behind new generation capacity.
Fuel and carbon costs also support high marginal power prices. At the end of October, Austrian CEGH gas was around €100/MWh, while Q1 2027 gas was around €98.5/MWh and EU carbon allowances were close to €89/t. With costs at those levels, a gas-fired plant setting the marginal price can require wholesale electricity prices above €200/MWh before scarcity premia are added.
Renewables can reduce the number of hours when gas sets the price, but do not eliminate expensive marginal pricing. For investors, the focus is shifting from capacity alone to the value of output in each hour. A solar plant producing during already-saturated midday hours has a different profile from a wind farm with broader daily output, a battery shifting energy into the evening or a pumped-storage plant with multi-hour duration.
For corporate power purchase agreements, an MWh’s value depends on delivery timing and whether the contract includes shaping, balancing or storage. Returning nuclear capacity and improved hydro inflows could ease prices through winter, but the outcome remains weather dependent. Cold conditions, weak wind and limited imports would leave Southeast Europe exposed to renewed scarcity prices.
