Cross-border capacity is the true currency of the South-East European electricity market. While power exchanges across the region are steadily developing, and while market coupling promises deeper integration and liquidity over time, the real competitive edge still rests with those players who understand the physical constraints of the network, who hold the strongest positions in long-standing cross-border auctions, and who know how to convert scarce interconnection rights into tradable optionality. In SEE—far more than in Western Europe—cross-border transmission is not merely a logistical requirement but a strategic asset. It determines price spreads, shapes arbitrage opportunities, and defines which traders can monetise the volatility created by thermal outages, hydrological swings, renewable imbalances and industrial demand shocks.
The advantage begins with scale and geographic reach. Traders like GEN-I, EFT, Axpo and Alpiq possess portfolios that span multiple countries, enabling them to arbitrage between price zones and to ride intraday volatility with a flexibility smaller traders cannot match. GEN-I, with its long-established presence in Slovenia, Croatia, Serbia, North Macedonia and Albania, enjoys the benefit of operating across a corridor of interconnected systems where congestion patterns are fairly predictable and where weather-driven volatility can be monetised if one holds the correct interconnection rights. Slovenia-Croatia, Croatia-Hungary, Serbia-Hungary and Bulgaria-Greece are among the most strategically valuable borders, and GEN-I’s strong positions in both Central European and SEE markets give it the advantage of understanding not only the Balkan-side fundamentals but also the behaviour of deeper, more liquid hubs such as Austria, Germany and Italy.
EFT holds a different type of advantage, one that stems from a long history of involvement in the region’s power flows. It understands intimately the physical bottlenecks between Bosnia and Herzegovina, Serbia and Montenegro, and it has been active for decades on borders such as RS-BA, BA-HR and RS-ME, which have their own unique congestion patterns. These borders may not be as liquid or as valuable from a flow-based market-coupling standpoint as the Central European corridors, but they hold enormous speculative value during periods of scarcity, rainfall shocks or thermal plant outages. EFT’s combination of regional familiarity, strong bilateral relationships with utilities and its legacy in managing physical generation assets gives it an ability to anticipate imbalances before they appear on exchanges. For a trader in SEE, that time advantage—sometimes no more than minutes, sometimes hours—translates directly into profit when cross-border rights are held and can be deployed flexibly.
Axpo and Alpiq bring yet another type of advantage: capital depth, ability to secure long-term transmission rights, and access to broader hedging instruments across the continent. Their presence on borders such as Romania-Hungary, Bulgaria-Greece, Bulgaria-Romania and North Macedonia-Greece allows them to straddle the frontier between SEE’s emerging markets and the EU’s mature ones. Greece, especially after the extraordinary volatility of 2022–2024, has become a high-value endpoint for Balkan flows. When Greek demand tightens, or when the local gas-fired fleet becomes margin-setting under high TTF conditions, price spreads between Greece and Bulgaria or North Macedonia widen dramatically. Traders who hold capacity on these borders can monetise these spreads through day-ahead, intraday or cross-product strategies. Axpo’s scale enables it to purchase transmission rights even when auction prices escalate sharply, a luxury that smaller regional traders cannot always afford.
Cross-border auctions themselves shape the hierarchy of market players. Monthly and annual auctions, run through JAO for many borders, reward traders who can withstand capital lock-up and forecasting uncertainty. GEN-I and Axpo in particular excel here because their portfolios allow them to diversify risk: if they overpay for capacity on a given border in a particular month, they can offset losses through their operations on other borders or through structured products. Smaller local players, even if they have excellent physical insight, often cannot compete at auction scale and must therefore rely on secondary capacity markets or short-term purchases, which significantly reduces their ability to construct forward strategies. The auction mechanism thus structurally favours traders with capital, cross-border diversification and the ability to manage long-term optionality.
Geography itself further entrenches competitive advantage. Slovenia sits at a natural crossroads between the Alpine region and the Western Balkans. It is heavily interconnected with Italy and Austria, which means that any trader with a strong position in Slovenia can access the volatility created by Italian gas markets, Austria’s deep liquidity and CEE’s generation patterns. GEN-I, rooted in Slovenia, understands these flows intimately and has historically exploited congestion on the SI-HR and SI-AT borders to move power into Croatia and Serbia when local markets tightened. During years of weak hydrology in the Balkans, the value of North-to-South flows increases significantly, and traders who hold rights on the Slovenia-Croatia border can extract premium spreads as Balkan utilities scramble to fill deficits.
Serbia holds a similar advantage but from the opposite angle. It is centrally located, tied to Hungary in the north, Bulgaria and Romania in the east, Montenegro and Bosnia in the west and south-west. When HUPX prices diverge from SEEPEX, or when Bulgarian exports tighten because of nuclear or renewable volatility, Serbia becomes the gateway through which value flows. EFT’s deep operational base in Serbia, combined with Axpo’s and Alpiq’s expanding presence, has made the RS-HU, RS-BG and RS-RO borders hotspots for profitable intraday strategies. Serbian system conditions, influenced heavily by EPS’s coal plant performance and hydrology, create frequent scarcity or surplus events, making cross-border flexibility essential.
The Bulgaria-Greece border is, however, arguably the single most strategically valuable interconnection in the region. As Greece has grown into a more dynamic market driven by renewables, industrial load, LNG pricing and frequent thermal unit cycling, price spreads between Greece and Bulgaria have become exceptionally wide at times. Traders holding rights on this border enjoy the kind of high-leverage arbitrage normally seen in pre-coupling Central Europe in the early 2010s. Here Axpo and GEN-I often outperform due to their ability to move large volumes, hedge exposure elsewhere, and absorb risk when congestion is uncertain. As Greece continues to integrate more renewables and reshapes its gas supply profile, the volatility on this border will only increase, solidifying its importance in regional strategy.
North Macedonia occupies a unique position, functioning as a transit node for flows between Greece, Serbia and Bulgaria. Market maturity is still developing, but traders with a presence here can monetise directional imbalances caused by outages in Kosovo, shortfalls in Albania or sudden shifts in Serbian system load. GEN-I has expanded into this geography early, which provides it with an advantage when flows must be rerouted or when local balancing needs spike unexpectedly.
Bosnia and Herzegovina remains a structurally coal-heavy system, but its position between Croatia, Serbia and Montenegro makes it an important balancing node in winter. When BiH struggles with thermal outages or low water inflow into hydro reservoirs, traders who hold rights on BA-HR or BA-RS borders can move power profitably into the country. EFT’s long-term presence gives it a level of operational foresight that few can match.
Montenegro, although small, wields disproportionate strategic importance because of the Italy-Montenegro submarine cable. While flows through this HVDC line have been more limited and gradual than originally expected, the long-term implication is clear: Montenegro will evolve into a transit and balancing hub linking Balkan volatility with Italian market depth. Traders who already operate in Montenegro or hold rights on ME-RS or ME-AL borders are likely to gain over time as flows become more sophisticated.
The structural advantage in cross-border trading ultimately rests on three pillars. The first is geographic footprint: traders who operate across many borders can diversify risk, internalise spreads, react rapidly to system imbalances and offset losses on one border with gains on another. The second is capital and scale: the ability to purchase long-term capacity rights at auction without fear of stranded cost gives traders optionality that others cannot match. The third is operational intelligence: the understanding of physical flows, hydrological behaviour, thermal fleet reliability, renewable patterns, political intervention risk and balancing-market mechanics. GEN-I and Axpo excel through scale and diversification; EFT excels through institutional memory and local system knowledge; Alpiq excels through cross-product integration and hedging capacity.
In the next five years, as market coupling expands and intraday platforms deepen, capacity holders will shift from pure arbitrage to flexibility management. Those who control storage, demand response assets, PPA portfolios or virtual power plant structures will be able to monetise volatility without relying exclusively on transmission rights. Yet until full coupling is achieved and Balkan grids undergo significant reinforcement, cross-border capacity will remain the kingmaker of SEE electricity trading. The geography of winners is already visible: Slovenia as the northern gatekeeper, Serbia as the central corridor, Bulgaria-Greece as the volatility magnet, and Montenegro as the long-term bridge to Italy. Traders entrenched in these spaces will continue to dominate the next cycle of regional electricity competition.
Traders and their cross-border advantages in the SEE electricity market
The circle of influential traders in the SEE electricity market extends well beyond the major names like GEN-I, EFT, Axpo and Alpiq. To understand the region’s competitive architecture, one must recognise that the Western Balkans have always attracted a unique blend of traders: long-established regional companies with deep historic roots, global commodity houses with vast balance sheets, and specialised originators positioning themselves to capture the accelerating renewable boom. Each of these actors shapes the cross-border landscape differently, in part because of their portfolio structure, in part because of the specific interconnection corridors they rely on, and in part because of their institutional knowledge—often accumulated over two decades of operating in an incompletely liberalised, politically volatile region.
Among the earliest and most regionally entrenched players is Rudnap Group, whose long-term presence across Serbia, Montenegro and Bosnia anchored its role as one of the formative private traders in the post-liberalisation period. Rudnap’s competitive advantage was never rooted in scale in the way that Axpo or Alpiq operate; instead, the company thrived through granular knowledge of local utilities, procurement procedures, generation patterns and cross-border bottlenecks. Its activity on corridors such as RS-BA, BA-HR and RS-ME allowed it to anticipate system imbalances at a time when data availability was limited and when local power exchanges either did not exist or were functionally embryonic. This embedded presence still matters: even though the regional landscape has evolved, traders like Rudnap who understand the political economy of state-owned utilities, the dispatch behaviour of thermal plants and the seasonal dynamics of hydropower continue to find profitable opportunities in bilateral trading, structured contracts and short-term arbitrage.
Another historic actor, Ezpada, brought a Central European trading mindset into the Balkans and built a portfolio that straddled both EU markets and SEE volatility. With Czech roots and a strong foothold in Hungary, Ezpada capitalised on the Hungarian-Serbian cross-border dynamics during periods of high congestion and price divergence. Its ability to trade gas and power simultaneously provided an edge in understanding how thermal generation costs impacted electricity spreads across borders such as HU-RS, RO-HU and BG-RO. While the company’s visibility has fluctuated over time, its cross-commodity intelligence remains emblematic of the type of trader that thrives in SEE: flexible, opportunistic, and deeply attuned to the physicality of the grid.
HSE, Slovenia’s state-owned generation company, occupies a hybrid space between utility, trader and originator. With Slovenia’s extensive hydro fleet forming the backbone of its portfolio, HSE holds a privileged position whenever rainfall patterns shift. In wet years, surplus hydro inflows allow HSE to export electricity into Croatia, Italy and Austria, making the SI-AT and SI-HR borders crucial vectors for commercial optimisation. In dry years, the opposite dynamic emerges and HSE becomes a structural importer. This cyclical behaviour gives HSE a nuanced understanding of Slovenia’s regional role as a northern anchor for SEE flows. Its trading subsidiary, HSE Energija, has become increasingly active across the Balkan borders, leveraging the company’s hydro flexibility to monetise intraday volatility, particularly when wind production in the region swings sharply.
CEZ, though primarily present through its assets in Bulgaria, remains one of the region’s most influential actors because of the country’s strategic position. Bulgaria is the hinge between the Balkans and the Black Sea region, and the interplay between Kozloduy nuclear output, Maritsa lignite generation and the sprawling solar expansion in southern Bulgaria shapes the ability of traders to move power into Romania, Greece and North Macedonia. CEZ’s dispatch-driven insight into Bulgarian supply conditions allows it to understand congestion patterns on the BG-GR and BG-RO borders with exceptional precision. When Greek prices spike because of gas-driven marginal cost, CEZ-backed traders who hold export capacity from Bulgaria into Greece capture spreads that can exceed triple-digit €/MWh levels during stress periods. When Romania experiences high wind output or seasonal surpluses, CEZ is among the first to adjust flows and arbitrage the resulting price dislocations.
MET Group, the Swiss-based trading house with strong Central European roots, has become increasingly influential across SEE. Its presence in Romania, Bulgaria, Croatia and Serbia gives it a multi-corridor perspective similar to GEN-I, but with a stronger emphasis on cross-commodity integration, particularly between gas and power. As Serbia and Bulgaria rely heavily on gas-fired peaking units to manage system tightness, MET’s expertise in gas procurement, storage optimisation and balancing positions it as a natural arbiter of short-term power scarcity. On borders such as RO-HU, BG-GR and HR-SI, MET uses its hedging capacity and intraday execution capability to arbitrage short-lived but highly lucrative imbalances. MET’s growing involvement in renewable PPAs across Hungary, Romania and Bulgaria also positions it as a likely future heavyweight in structured renewable products in SEE.
Another major force increasingly shaping SEE cross-border trading is Statkraft, Europe’s largest renewable producer. Though Statkraft initially approached SEE primarily as a route for green certificate strategies and cross-portfolio balancing, it has since expanded its trading presence in Romania, Bulgaria and Western Balkans-adjacent markets. Statkraft’s hydro-optimised portfolio and extensive forecasting machinery give it a sophisticated understanding of renewable-driven congestion. When Balkan hydro inflows spike—particularly in spring—Statkraft is well-positioned to redirect surplus flows through Romania into Hungary or from Bulgaria into Greece. Conversely, in drought years the company can leverage its Northern European renewable portfolio to supply SEE markets when scarcity premiums emerge. Statkraft’s analytical depth in weather modelling and renewable correlation patterns gives it a scientific edge that few regional traders can replicate.
Danske Commodities, with headquarters in Denmark and a reputation as one of Europe’s sharpest short-term traders, has been gradually deepening its SEE presence as well. Its strength lies in intraday optimisation and algorithmic execution, a domain that becomes increasingly valuable as the Balkans integrate more wind and solar capacity. The company’s experience navigating Germany’s highly volatile intraday markets translates naturally to SEE conditions, where intraday spreads often remain wide due to incomplete coupling, weak forecasting infrastructure and sudden renewable-driven imbalances. Danske Commodities is particularly effective on the GR-BG, RO-HU and HU-HR corridors, where it can deploy automated strategies to capture real-time price spikes.
On a more localised scale, Croatian ENNA, Serbian Proenergy and several boutique traders in North Macedonia, Albania and Montenegro contribute to the region’s liquidity. Their competitive power does not stem from scale but from proximity: knowing which plant in Bosnia is likely to trip, which distribution company in Kosovo is facing seasonal imbalance, or when Albania’s hydrology will suddenly reverse. Local traders often understand nuances that foreign traders discover only after the fact. When local conditions shift abruptly—as they frequently do—these smaller entities execute faster, call the right counterparty within minutes, and monetise opportunities before they appear on formal markets.
The increasing involvement of renewable developers, financiers and PPA aggregators is also reshaping competition. As wind and solar capacity accelerates across Serbia, Romania, Greece, Bulgaria and Albania, new classes of traders are emerging: originators who structure long-term PPAs, intermediaries who aggregate generation portfolios, and balancing service providers who specialise in profiling risk for intermittent assets. Companies like Statkraft, Axpo, GEN-I, MET and even smaller originators now operate not just as traders but as risk carriers along the renewable value chain. The more renewable capacity enters the system, the more valuable the balancing and flexibility layer becomes—and with it, the more traders transform into service providers.
The cross-border advantage of these additional players depends heavily on geography. CEZ dominates strategic flows out of Bulgaria; HSE controls hydro-driven flexibility exiting Slovenia; MET leverages its multi-border gas-power integration; Statkraft uses renewable forecasting to manage congestion; Ezpada and Rudnap thrive where local knowledge is decisive; Danske Commodities excels where intraday volatility remains unstructured; smaller Balkan traders navigate municipalities and utilities that global firms cannot easily reach. Together they form a layered ecosystem, where different actors control different segments of cross-border opportunity.
What unifies all of them is the understanding that cross-border capacity is not only a physical right but a financial instrument—an option on volatility. Traders with scale, whether GEN-I, Axpo or MET, purchase transmission rights as part of long-term strategy, absorbing periods of low value in exchange for occasionally extraordinary returns when spreads explode. Traders with local knowledge—Rudnap, Proenergy, GSA—use agility and intelligence to monetise marginal conditions. Traders with renewable and hydro-driven portfolios—Statkraft, HSE—internalise the physics of the system. And traders with algorithmic machinery—Danske Commodities—profit from intraday chaos.
As SEE moves toward deeper integration, market coupling and renewable expansion, these additional players will not disappear; instead, their roles will sharpen. Local players will handle granular constraints; global traders will arbitrage structural spreads; renewable originators will manage intermittency; and hybrid giants like GEN-I, Axpo, MET and Statkraft will act as the orchestrators of a progressively more complex energy ecosystem. Cross-border capacity will remain the defining asset, and those who understand its value—not as infrastructure, but as optionality—will continue to dominate the landscape.
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