In the first half of May 2026, prices rose across almost every major Southeastern Europe market, but not uniformly. Trading is increasingly described through corridor economics rather than country-by-country market structure. The corridor map cited for the region runs across Greece–Bulgaria–Romania, Serbia–Hungary, Bosnia–Serbia–Croatia, and Montenegro–Albania–Italy-linked flows, alongside an emerging gas-and-power axis from the Eastern Mediterranean toward Central Europe.
Market averages for the period were reported as follows: Romania’s OPCOM averaged €115.88/MWh, Hungary’s HUPX €108.62/MWh, Croatia’s CROPEX €105.77/MWh, Bulgaria’s IBEX €104.98/MWh, Serbia’s SEEPEX €101.61/MWh, Montenegro’s BELEN €98.76/MWh, and Albania’s ALPEX €98.60/MWh. The spread pattern indicates that national averages remain relevant, while the commercial story increasingly depends on where electricity can move and which corridor captures scarcity.
Cross-border flows show a shift toward import dependence
The clearest signal cited for the corridor shift came from cross-border flows. Net exports across the broader HU+SEE region deteriorated from -767 MW to -1,170 MW, indicating a more structurally import-dependent position. Flows toward Italy reversed from +310 MW to -148 MW.
At the same time, the Bulgaria–North Macedonia–Albania position toward Greece weakened to -1,129 MW. The reported changes are linked to interactions among generation, demand, solar output, hydro availability, nuclear outages and cross-border capacity.
From national generation mixes to corridor value
Earlier regional analysis relied on national generation mixes: Serbia described as coal-heavy; Montenegro as hydro-sensitive; Bosnia and Herzegovina as coal-and-hydro based; Romania as hydro-nuclear-thermal; Bulgaria as nuclear-coal-solar; and Greece as gas-and-renewables driven. That framework is described as still useful but no longer sufficient for explaining market value.
The material value is presented as sitting in corridors between those systems. Under this approach, a renewable project in Serbia is treated as depending on access toward Hungary, Romania, Bosnia and Herzegovina, Montenegro and North Macedonia within the wider coupled structure. A hydropower asset in Montenegro is described as depending on Italian spreads, Albanian flows, Serbian liquidity, CBAM treatment and regional congestion.
Storage is also framed through corridor placement. A Bulgarian battery is described as a flexibility asset inside a corridor linking Greece, Romania, Turkey, North Macedonia and Central Europe.
Greece–Bulgaria–Romania becomes a southern-to-central balancing corridor
The first corridor highlighted is the Greece–Bulgaria–Romania axis. Greece is described as becoming renewable-heavy with gas linkage and LNG-enabled supply characteristics alongside rising solar curtailment risk. Bulgaria is described as moving into storage while remaining strategically important through nuclear and solar generation and cross-border positioning.
Romania is described as combining hydro, nuclear, wind and solar with growing industrial demand while facing network connection and grid-access pressure. Together, these markets are described as forming a southern-to-central balancing corridor in SEE.
Gas linkage ties power prices to fuel availability
Gas is cited as strengthening that role through multiple infrastructure elements including the Vertical Gas Corridor and the Alexandroupolis LNG route. Bulgarian transmission infrastructure and Romania’s gas and power system are also referenced as creating a combined energy corridor where gas availability and electricity prices interact.
The material links marginal price setting to corridor value: when gas becomes the marginal price setter, the corridor is described as more valuable; when renewables oversupply one zone while scarcity appears in another, the corridor captures the spread.
Serbia–Hungary spreads reflect an interface between Western Balkans and Central Europe
The second corridor highlighted is Serbia–Hungary. It is described as a strategic interface because Hungary often functions as a Central European price anchor while Serbia sits at the crossroads of Western Balkan flows.
For May trading averages were cited at €108.62/MWh for HUPX versus €101.61/MWh for SEEPEX. The reported spread places Serbia at a discount to Hungary.
The spread is presented as creating trading value while also signaling Serbia’s potential role in balancing and transit activity. The same material notes that if Serbia strengthens transmission capacity, market liquidity, storage deployment and industrial renewable procurement it could act as a corridor hub rather than only a national system.
If grid bottlenecks persist, Serbia is described as facing a risk of operating as a congestion buffer between stronger surrounding markets.
Bosnia–Serbia–Croatia faces coal stress alongside hydro potential
The third corridor highlighted is Bosnia and Herzegovina–Serbia–Croatia. It is described as being shaped by coal instability, hydro potential and transmission constraints.
Bosnia is cited as having significant generation resources but with reliability weakened by project delays, coal-plant stress and governance fragmentation. Serbia is cited for providing scale and centrality, while Croatia connects the region toward Slovenia, Hungary and Adriatic market space.
Coal instability within this corridor is illustrated using company-reported financial outcomes: RiTE Ugljevik reported a €18.3 million first-quarter loss after production disruptions; RiTE Gacko reported profit falling to around €50,000.
When coal plants become less reliable in this corridor, cross-border flows and regional prices are described as becoming more volatile.
Montenegro–Albania–Italy-linked flows combine hydropower with storage build-out
The fourth corridor highlighted is Montenegro–Albania–Italy-linked flows. It is described as combining hydropower with emerging wind generation plus solar-plus-storage development alongside Adriatic export logic.
Montenegro’s EPCG is cited as having felt CBAM-related export pressure with an estimated €13 million revenue impact in the first quarter of 2026. Albania is cited for moving toward bankable solar-plus-storage via a 160 MW solar project paired with 60 MW BESS backed by a proposed €53 million EBRD loan within total investment of around €105 million.
This corridor is described as potentially becoming one of SEE’s flexibility zones through combinations of hydro output, solar generation, storage deployment and export positioning. The same material states that outcomes depend on traceability requirements, grid access conditions, cross-border rights and storage integration.
A future gas-power-industrial axis links Greece with Central Europe
The fifth corridor highlighted involves a future gas-power-industrial link connecting Greece, North Macedonia, Serbia and Central Europe. The decision by Serbia and North Macedonia to join the next phase of discussion on the Vertical Gas Corridor is described as extending beyond gas supply into industrial energy security and power-system flexibility.
The same material links growing importance to industrial exporters’ need for reliable energy that can be traced and priced competitively under CBAM pressure. Gas flexibility together with renewable PPAs, storage capacity and cross-border electricity access are described as being evaluated together rather than separately.
Electricity markets are therefore framed alongside gas supply considerations under an investment logic that converges electricity trading with carbon exposure under CBAM treatment and grid infrastructure planning across corridors including Romania–Hungary, Serbia–Hungary, Bulgaria–Greece, Montenegro–Albania and Bosnia–Serbia alongside Greece–Italy-linked dynamics.
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