In the first half of May 2026, gas-fired output moved back toward the center of electricity price formation across the broader HU+SEE system. Over the observed period, gas generation increased by about 362 MW, while total regional electricity demand fell by roughly 1,018 MW. At the same time, nuclear output declined by 1,686 MW, coal generation dropped by 260 MW, and hydro output weakened by another 357 MW.
That generation mix shift coincided with tightening balancing conditions as renewable volatility increased and thermal reliability weakened across the region. With less contribution from nuclear, coal and hydro, gas was drawn into the marginal balancing role. The market response followed quickly in multiple national power exchanges.
Regional power prices rise as dispatch mix tightens
Romania’s OPCOM jumped to €115.88/MWh, while Hungary’s HUPX reached €108.62/MWh. Bulgaria’s IBEX climbed to €104.98/MWh, Croatia’s CROPEX averaged €105.77/MWh, and Serbia’s SEEPEX moved above €101/MWh. These levels were recorded despite weaker consumption and improving temperatures.
The same period also showed a link between higher thermal marginality and the availability of balancing capacity. Gas remained the technology described as most capable of closing the balancing gap under the prevailing operating conditions. The price pattern indicated that marginal generation scarcity increasingly influenced electricity pricing rather than demand alone.
Thermal outages and maintenance affect baseload availability
Alongside the gas increase, multiple baseload segments experienced reductions tied to outages and maintenance. Nuclear generation saw significant interruptions, including Bulgaria’s Kozloduy Unit 5 entering maintenance and Romania’s Cernavoda Unit 2 remaining affected by extended technical issues.
Coal performance also deteriorated across parts of the Western Balkans. RiTE Ugljevik spent months offline before returning to operation in early May, while RiTE Gacko reported sharply deteriorating profitability. Montenegro’s Pljevlja coal operations also showed worsening financial performance.
Renewables expand while balancing needs shift toward flexibility
Renewable deployment continued across several markets including Bulgaria, Greece, Romania, Serbia and North Macedonia. The source data links this build-out with increased hourly balancing requirements, particularly during evening ramps, low-wind periods and seasonal hydro fluctuations. Solar and wind growth was described as continuing rapidly even as renewable output alone could not stabilize hourly dynamics.
The operational profile described for the region includes daytime oversupply alongside evening scarcity as solar output rises. Gas is presented as a bridging resource under these conditions because it can ramp quickly compared with coal and can provide balancing without hydrological constraints that affect hydro operations. The same comparison also places gas ahead of batteries for extended-duration balancing under current storage limitations referenced in the source.
Gas infrastructure role expands alongside interconnection plans
The changing dispatch environment affects how regional gas infrastructure is positioned for electricity system stability. Projects cited include the Alexandroupolis LNG terminal, the Vertical Gas Corridor, and expanded interconnections across Greece, Bulgaria, Serbia and North Macedonia. Earlier discussions emphasized diversification away from Russian supplies.
The corridor is also tied in the source to growing recognition that gas interconnectivity supports electricity market stability as renewables penetration increases. Corridor expansion discussions involving Greece, Serbia, Bulgaria and North Macedonia are framed around this stability need rather than supply diversification alone.
LNG market volatility keeps gas prices elevated despite lower pipeline flows
The source points to continued uncertainty in gas supply conditions affecting pricing even when physical flows decline. TurkStream deliveries to Europe fell again in April, decreasing both month-on-month and year-on-year. Despite lower pipeline volumes, gas prices remained elevated due to geopolitical volatility in global LNG markets linked to Middle Eastern disruptions and tighter supply competition.
This combination is described as creating a policy tension for Southeast Europe because additional flexibility is needed while long-term procurement becomes more geopolitically and financially uncertain. Investment decisions are therefore shaped by simultaneous pursuit of multiple options across power and gas infrastructure.
Fuel costs, carbon prices and trading signals shift with thermal marginality
The period also included data on gas hub pricing and carbon costs relevant to thermal dispatch economics. CEGH gas prices averaged about €46.64/MWh, while Greek gas prices remained near €45.22/MWh. Carbon prices were around €74.96/t, with fuel-plus-carbon cost levels still supporting elevated thermal marginal pricing.
The source also describes changing drivers for power trading behavior in Southeast Europe. While earlier market focus centered on hydro conditions, coal availability and seasonal demand swings, it states that gas spreads, LNG flows, storage levels and balancing fuel availability increasingly influence electricity pricing outcomes on regional exchanges.
Project finance focus shifts toward flexible generation capability
The implications for investment are described through utilization expectations for different asset types capable of providing balancing services. Gas-fired assets are referenced as regaining value as balancing providers compared with earlier perceptions of strategic vulnerability. The source cites combined-cycle plants, flexible peakers and hybrid gas-renewable systems as potentially seeing stronger utilization assumptions than investors anticipated several years ago.
At the same time, it notes that pure baseload exposure remains exposed to decarbonization pressure and carbon price escalation referenced in the source data. It also states that a premium is increasingly associated with flexibility—assets that can ramp quickly, participate in balancing markets and stabilize renewable-heavy grids—whether they are gas turbines, hydro reservoirs or battery systems.
Sovereign energy strategies emphasize combined flexibility resources
The same framework is applied to country-level energy strategies combining multiple elements listed in the source: flexible gas access, renewable generation, battery storage, cross-border interconnections, hydropower balancing and industrial demand response. Countries able to combine these components are described as likely achieving stronger pricing stability and energy security than systems relying heavily on a single generation source.
Greece is identified as increasingly positioned within this structure due to its LNG infrastructure, interconnection investments and expanding renewable base tied to emerging SEE energy corridors. The source also highlights Bulgaria’s storage deployment and transmission positioning and notes Serbia’s central geographical role linking Central Europe with the Balkans alongside future corridor expansions.
The changes described extend beyond electricity trading into industrial energy requirements referenced in the source data. It lists industrial competitiveness factors including data center development, hydrogen projects and aluminum processing economics, along with regional export structures that depend on reliable flexible energy supply rather than only low-cost generation.