Yearly net power cross-border capacity (CBC) costs switched for key directions in central and southeast Europe for 2026, reflecting structural changes to flows.
Nearly 400MW in the Greece-Bulgaria auction sold at €7.56/MWh — the highest for the direction since Jao platform auctions began in 2019. And it cleared €5.87/MWh above the opposite direction, switching from a €0.76/MWh discount for 2025. This was the first time the Greece-Bulgaria direction cleared above the reverse, reflecting this year's changes to cross-border flows. Bulgaria has net exported just 2MW to Greece in the year to 10 December, well below the 302MW five-year average for the period, with Greece net exporting to Bulgaria in seven of the 11 full months of 2025. Greece has net exported 250MW to neighbouring countries, switching from 79MW of net imports in January-November 2024.
Greece's net exports have been underpinned by renewable additions. The country's solar capacity was 9.9GW at the end of September, up by 21.5pc on the year, while wind capacity has risen by 4pc to 5.44GW. Wind and solar output have averaged almost 2.7GW in 2025, accounting for 46pc of Greece's mix, up by two percentage points on the year.
Greece aims to have phased out lignite-fired generation by the end of 2026 and has already started replacing this with renewables and high-efficiency combined-cycle gas turbines (CCGTs). The 810MW Komotini CCGT is undergoing testing and expected to be operating commercially next year.
Greece's first battery energy storage systems (Bess) will start operating next year — PPC has 146MW under constriction. Expectations that Greece will maintain net exports next year are also reflected in forward values, with the Greek 2026 contract most recently assessed at €95.15/MWh — €6.75/MWh below Bulgaria and at a €8.95/MWh discount to Romania and Hungary.
Net CBC costs also flipped on the Romania-Hungary border. The 350MW Romania-Hungary CBC for 2026 sold at €3.58/MWh, its lowest in four years, but €1.07/MWh above the opposite direction, switching from a €0.60/MWh discount for 2025.
This is despite Romania having net imported 592MW from Hungary in 2025, up by 248MW on the year and the most for the period in more than five years. That has brought overall Romanian net imports to 736MW, up by 313MW on the year and also a more than five-year high. The Romanian 2026 contract has regularly switched between a premium and a discount to Hungary since assessments began, having been at discount on 23 September-4 December, before being assessed at parity in the past three sessions.
Romania has negotiated with the EU postponement of its lignite phase-out to the end of 2029, pushing back from the end of next year.
Romania added 1.23GW of solar capacity over the first 11 months of 2025, up from 303MW in all of 2024. Solar capacity stood just above 3GW at the end of November, while solar output has averaged 327MW in 2025, up by 75MW on 2024. But just 41MW of wind has been added this year, down from 69MW in 2024.
Romania has not added any thermal capacity in recent years, while commercial operations at its long-awaited 430MW Iernut CCGT — previously expected at the end of this year — have been pushed back to the second quarter of 2026. The 1.75GW Mintia CCGT is due to come on line by the end of next year.
Romania will also enter 2026 with hydro stocks at surpluses to a year earlier and the five-year average. Reserves were at 2.15TWh, or 73pc of stored energy potential, in week 49 — 308.2GWh up on the year and 130GWh above the five-year average.
And new trends could be emerging in other CBC auctions. The 2026 CBC auctions on Serbia's borders with Bulgaria and Hungary close on 15 December, with 150MW and 200MW, respectively, available. For 2025, the 150MW Bulgaria-Serbia direction sold at €2.96/MWh, or €0.86/MWh above the reverse direction, while the 200MW Serbia-Hungary cleared at €4.40/MWh, almost the same as the reverse. But based on the forward market, the former could flip for 2026, while the latter could be sold at a large premium to the opposite.
Argus most recently assessed the Serbian year-ahead at €96.85/MWh — a €5.50/MWh discount to Bulgaria and €7.25/MWh below Hungary. Risk from implementation of the EU's carbon border adjustment mechanism (CBAM) — centred on unclear methodology and delayed payments — will reduce cross-border demand from strong importers such as Hungary, creating oversupply in the six western Balkan countries, including Serbia, market participants have told Argus. Uncertainty around CBAM has already led Turkish transmission system operator Teias to delay the 2026 Turkey-Bulgaria CBC auction.
