Southeast European electricity markets showed a shift in trading conditions as solar generation volatility, flexibility resources and grid capacity increasingly influenced value. Weekend demand combined with strong photovoltaic output pushed day-ahead prices lower for Sunday delivery, followed by a rebound the next day. The weekend decline was linked to lower consumption and renewable oversupply rather than a change in structural market fundamentals.
On Sunday, SEEPEX cleared at €72.62/MWh for baseload and €37.61/MWh for peak hours, with traded volume of 14,547.4 MWh. Regional pricing remained broadly aligned, with Romania, Bulgaria and Greece averaging close to €80/MWh. Hungary averaged around €81/MWh, Croatia at €82.27/MWh, and Slovenia at approximately €84/MWh.
Daily averages did not reflect the intraday pattern seen across Bulgaria, Greece, Hungary, Romania, Croatia and Slovenia. Prices fell close to €0/MWh between 10:00 and 15:00 as solar output peaked before rising toward €145/MWh during evening hours when photovoltaic generation fell away and demand stayed elevated. The resulting spread of almost €145/MWh pointed to the role of storage and flexible generation alongside transmission availability.
SEEPEX pricing diverges between midday lows and evening highs
The market structure is increasingly moving away from traditional baseload economics as value concentrates on assets that can shift electricity across time periods. Resources that can absorb excess renewable output during low-price hours and supply power during high-demand periods are positioned as more relevant to trading outcomes. This change is reflected in the observed intraday swings tied to solar generation profiles.
Serbia traded at a discount versus neighbouring EU-coupled markets, with SEEPEX prices around €7–11/MWh lower. The lower level was associated with strong domestic supply conditions and a regional solar-driven surplus during the low-demand Sunday session. Complete harmonised physical-flow data from all regional transmission operators were not yet available at the reporting deadline, limiting bilateral flow analysis.
The weekend weakness did not persist into the next delivery day. For Monday delivery, SEEPEX published a baseload price of €97.53/MWh, up almost 34% from Sunday, while peak prices rose to €78.83/MWh. Traded volume increased to 15,746.3 MWh, indicating that the earlier decline was mainly driven by calendar effects and renewable output patterns rather than weaker Serbian fundamentals.
Implications for merchant solar and battery revenue exposure
The price curve highlighted limits of using annual average electricity prices for project profitability assessments. Merchant solar projects are required to account for zero-price periods, curtailment risk and imbalance exposure alongside declining midday capture prices. Battery projects may benefit from larger spreads, but commercial outcomes depend on cycling limits, degradation management and participation in balancing activities.
Battery revenue also depends on the ability to generate returns across multiple market segments rather than relying only on simple arbitrage opportunities. These considerations align with the intraday pattern observed during periods of high photovoltaic output followed by evening price increases. The trading results therefore feed into how storage operators evaluate market access across day-ahead, intraday and balancing timeframes.
European gas prices ease while power markets remain exposed
European gas prices ended the week at €48.80/MWh on 10 July, down 2.91% on the day but still about 37% higher year on year. Earlier in the week, prices rose by more than 12% amid renewed geopolitical concerns related to US-Iran tensions and potential risks to LNG flows through the Strait of Hormuz.
Brent crude closed at $76.01 per barrel, down slightly on Friday but still around 5.5% higher over the week. Even with LNG vessels continuing to pass through Hormuz, reduced shipping activity supported a geopolitical risk premium. Gas-fired generation in markets including Greece and Romania therefore remained exposed to fuel-price volatility during periods of weak electricity demand.
Greek LNG flows support regional supply routes
Greece’s role as a gas hub expanded in early 2026 figures cited in the report. Total Greek gas consumption reached 43.09 TWh in the first half of 2026, up 15.06% year on year, while exports rose to 8.72 TWh from 2.86 TWh. Domestic demand remained relatively stable at 34.37 TWh.
The Revithoussa LNG terminal supplied 18.61 TWh, representing about 43% of incoming gas volumes. Flows through the Alexandroupoli FSRU increased more than threefold to 3.46 TWh. The figures indicate that Greek LNG infrastructure is increasingly supporting neighbouring markets including Bulgaria and countries further north.
LNG-linked power economics remained sensitive to LNG availability, transportation costs, transmission tariffs and geopolitical developments cited in the report. This sensitivity affects how gas-fired generation costs translate into electricity market outcomes even when power demand is weak.
Bulgaria’s Vertical Gas Corridor moves toward capacity auctions
Bulgaria’s energy security role is expected to strengthen as projects under the Vertical Gas Corridor approach completion. Bulgartransgaz expects key network sections to be ready by 1 October 2026, after which additional capacity will be offered through annual auctions.
Around 80% of the 48 km Kulata–Kresna pipeline section has already been welded and installed. The planned Rupcha–Vetrino expansion is intended to increase northbound transmission capacity along a route connecting Greece, Bulgaria, Romania, Hungary, Slovakia, Moldova and Ukraine.
The corridor is described as moving from strategic planning into commercial utilisation based on long-term capacity bookings, competitive tariffs and actual market demand. For generators and industrial consumers it provides supply flexibility, while for infrastructure investors contracted capacity determines revenue security.
GEN-I targets managed battery capacity across Slovenia and Bulgaria
GEN-I is positioning itself as a storage operator in Southeast Europe with a target of approximately 800 MW of managed battery capacity by end-2026. In Romania, GEN-I Sonce signed a turnkey agreement with Waldevar Energy for a 110 kV, 63 MVA substation and grid connection infrastructure supporting a planned battery project of 55 MW / 225 MWh. Waldevar will deliver engineering, procurement, construction, testing and commissioning services.
The company also expanded its Bulgarian portfolio through acquisitions of the Belovo, Momchilgrad and Parvomay 1 battery projects totalling 30 MW / 76 MWh. Together with the 12 MW / 24 MWh Kidričevo facility in Slovenia, GEN-I owns approximately 42 MW / 100 MWh. Additional acquisitions are planned.
Romania brings Stâlpu hybrid solar-plus-storage projects into trial operation
MORE placed Stâlpu 2 into trial operation in Buzău County.
Cyclades interconnection completion supports Greek renewable integration
The Greek transmission operator IPTO completed the final phase of the Cyclades interconnection project connecting Santorini, Folegandros, Milos and Serifos directly with the mainland system through Attica. The wider programme represents an investment of approximately €825 million including a final phase valued at €385.7 million.
The final phase involved 294 km of 150 kV submarine and underground cables, along with four digital substations cited in the report. The project reduces reliance on island diesel generation while adding capacity for renewable development.
ELES joins PICASSO reserve platform and prepares MARI connection
ELES joined the European PICASSO automated frequency-restoration reserve platform on 1 July. It is preparing to connect to the MARI manual balancing platform on 15 July. The changes expand access to balancing markets for technologies including batteries, hydropower and flexible demand.
Tender framework advances geothermal energy and geological CO₂ storage in Croatia
Croatia is creating a legal framework covering hydrocarbons, geothermal energy and geological carbon storage. Legislation adopted by the government introduces new tender models allowing existing wells and production fields to be repurposed for geothermal projects and CO₂ storage.
Batteries, grid upgrades and balancing platforms expand flexibility options across the region
The report links ongoing solar growth with larger intraday price swings while highlighting storage deployment alongside grid upgrades and balancing-market participation as key elements of system flexibility development in Southeast Europe.