As South-East Europe (SEE) advances in its renewable energy development, it faces critical challenges reminiscent of those encountered by Western Europe. The region has enjoyed a favorable investment climate characterized by abundant solar irradiation, underdeveloped wind resources, and relatively low land costs. This environment has attracted developers to countries including Serbia, Romania, Greece, Bulgaria, Montenegro, Albania, and Bosnia and Herzegovina, who anticipated that increased renewable capacity would be essential for meeting domestic electricity needs and achieving lower-carbon energy goals.
However, projections for 2026 indicate that more mature markets in SEE are beginning to exhibit signs of a potential oversupply crisis. This phenomenon—marked by concentrated renewable generation at specific times—risks leading to falling capture prices, grid congestion, and increased curtailment. The challenge is not the lack of demand for renewable energy but rather the timing and volume of its delivery into grids that may not be equipped to handle such variability.
Greece serves as an early indicator of these issues. The rapid deployment of solar energy has resulted in significant price compression during peak sunlight hours when demand remains moderate. This trend highlights the urgent need for enhanced battery storage solutions, interconnections, and flexible balancing resources to manage the influx of solar energy effectively.
Bulgaria is similarly experiencing pressure as solar capacity expands rapidly within a legacy system still reliant on coal and nuclear power. The increasing prevalence of high solar output periods is weakening midday prices and elevating the importance of flexible assets. Romania’s electricity landscape is more diversified due to its nuclear and hydroelectric resources; however, with ambitious plans for offshore wind in the Black Sea and expanding solar capacity, it too could face oversupply challenges if investments in grid infrastructure and storage do not keep pace.
Serbia is beginning this transition from a different baseline, still heavily dependent on lignite generation. While it has not yet reached the saturation levels seen in Greece, developments in wind energy in Vojvodina and planned battery storage projects totaling approximately 4.54 GWh indicate a shift towards accommodating a more variable energy system.
The pressing question remains whether SEE can sidestep the pitfalls experienced by Western Europe. The region holds several advantages: lower current levels of renewable penetration provide time for governments and transmission system operators (TSOs) to enhance integration strategies. Moreover, hydropower resources in Albania, Montenegro, Bosnia and Herzegovina, and Romania offer balancing capabilities that many Western European systems currently lack. Improved regional interconnections, such as the Trans-Balkan Corridor project, could further bolster cross-border flexibility among these countries.
Recent observations from the Energy Community reveal a notable shift in electricity flows between the EU and the Western Balkans during Q1 2026. Commercial exchanges decreased by approximately 25%, with EU-to-WB6 flows declining even more significantly. These trends underscore that interconnection capacity and carbon pricing structures are pivotal in determining whether surplus renewable energy can be transformed into exportable value or become stranded assets.
If SEE fails to synchronize grid expansion with storage development and market integration efforts, the consequences could be severe. Solar developers may confront deteriorating capture prices while wind projects deal with congestion penalties imposed by TSOs. In turn, lenders could increase risk premiums, prompting investors to pivot away from standalone generation toward hybrid solutions or more established markets.
The primary issue lies not in an excess of renewable energy per se but rather in poorly timed deliveries into systems that cannot absorb them effectively. Battery energy storage systems (BESS) represent a crucial first line of defense against this challenge by absorbing peak solar output and mitigating negative price impacts during oversupply periods. Countries like Greece, Serbia, and Romania are already pursuing these technologies; however, future demands will likely exceed current development pipelines.
Hydropower also plays a vital role in providing flexibility; optimizing reservoir dispatch across Albania and Montenegro could yield significant benefits if aligned with regional volatility rather than solely domestic needs. Romania’s hydroelectric fleet further enhances its position as offshore wind and solar projects expand.
Strengthening transmission networks is equally essential for facilitating the movement of surplus renewable energy towards demand centers or balancing assets. Projects like the Montenegro–Italy cable and various interconnections among Serbia, Romania, Greece, and Bulgaria are critical components of this infrastructure strategy.
Demand-side flexibility represents another key area for improvement. Encouraging industrial consumers and other large electricity users to adjust their consumption during low-price periods can help stabilize markets significantly. This is particularly relevant for sectors such as tourism in Greece or manufacturing in Romania.
The financing landscape must also evolve; while previous cycles focused on financing megawatts of generation capacity alone, future investments will need to prioritize flexibility solutions that integrate generation with storage capabilities and active trading strategies. Infrastructure funds are likely to favor portfolios adept at managing market volatility over those that merely produce electricity.
South-East Europe still possesses a window of opportunity to avert significant challenges associated with renewable oversupply akin to those faced by Western Europe. However, this window is closing as renewable buildout accelerates faster than necessary market adaptations occur. Without concurrent investments in storage solutions, grid interconnections, and balancing mechanisms alongside ongoing project expansions, oversupply risks will likely dominate the late-2020s landscape within SEE electricity markets.
