By 2025, solar photovoltaic (PV) energy has transitioned from a marginal contributor to a fundamental element of the energy landscape in Southeast Europe. This shift is characterized by significant increases in solar output, which not only generates substantial terawatt-hour volumes but also influences market dynamics, including pricing mechanisms and import/export balances. The impact of this transformation varies across countries, but the overarching trend illustrates how solar energy is reshaping consumption patterns and trading practices within the region.
Greece leads the region with over 7.8 gigawatts (GW) of installed solar capacity, producing approximately 13 to 14 terawatt-hours (TWh) annually. During peak midday hours, solar generation frequently meets 30-35% of Greece’s instantaneous demand, resulting in notable drops in wholesale prices and enabling exports to neighboring markets such as Bulgaria and Italy. This consistent surplus during sunny periods has established Greece as a net electricity exporter during daylight hours, a significant evolution from its previous status in the early 2020s.
Bulgaria follows closely with an installed PV capacity of around 4.8 GW by mid-2025, up from just over 3.5 GW at the beginning of that year. Annual solar output reaches approximately 6-6.5 TWh, representing more than 15% of the country’s total electricity generation. This growth has enhanced Bulgaria’s export capacity, with net electricity exports nearing 11 TWh in the first three quarters of 2025—a year-on-year increase driven by solar generation during peak seasons.
Romania’s rapid expansion in solar capacity has led to around 4.1 GW installed by 2025, generating between 5.5 and 6 TWh per year. Solar now accounts for over 8% of Romania’s overall generation and plays a critical role in shaping intraday electricity flows. Net exports tend to peak between late morning and early afternoon on sunny days, while evening demand continues to rely on gas and nuclear sources for flexibility.
Croatia’s solar capacity is smaller but growing quickly, with about 1.1 GW installed by 2025. This translates to an annual generation of approximately 1.4-1.6 TWh, which constitutes about 7-8% of national electricity production. The increased solar contribution has already begun to alleviate peak import requirements during low-hydro years.
The Western Balkans are also witnessing growth from a lower base; Serbia had roughly 400-450 MW of PV capacity by mid-2025. This marks a significant increase from less than 200 MW in early 2023, producing nearly 0.5 TWh annually—still under one percent of total generation but enough to impact daytime demand peaks significantly. Montenegro and North Macedonia also show promise with their respective capacities contributing modestly yet meaningfully to local energy needs.
Albania’s solar installations reached around 350 MW by mid-2025, yielding approximately 0.55–0.6 TWh annually. While this remains below ten percent of Albania’s hydro-dominated energy mix, it diversifies the energy supply and reduces dependency on high-cost imports during dry periods.
The cumulative effect across Southeast Europe sees solar generation exceeding approximately 30–32 TWh annually—still below hydropower’s average output but surpassing earlier projections for this phase of transition. The strategic implications are profound: solar is now a pivotal factor influencing regional import/export balances and market pricing structures.
This transition also brings challenges; increased reliance on solar necessitates enhanced balancing energy solutions. The rapid ramp-up and decline of PV output throughout the day require flexible resources to maintain grid stability. In a scenario where total installed PV reaches around 15–16 GW across the region, managing these fluctuations becomes critical for grid operators.
Hydropower remains the primary source for balancing energy in Southeast Europe. Reservoirs across Serbia, Bosnia and Herzegovina, Montenegro, Bulgaria, and Romania provide essential flexibility due to their ability to quickly adjust output levels in response to variable solar production. However, hydrological constraints can limit their effectiveness during dry years when water reserves must be conserved for energy production rather than ancillary services.
Gas-fired power plants are emerging as another crucial component for balancing supply-demand dynamics. In Greece and Romania particularly, modern gas units play a vital role in meeting residual demand as solar generation diminishes at dusk or during cloudy conditions. These plants are increasingly recognized as valuable assets due to their ability to provide capacity rather than just energy output.
Cross-border transmission capabilities also serve as an important mechanism for managing excess daytime solar production. Countries can export surplus power when local demand is low; however, as more nations increase their solar penetration simultaneously, this strategy may face limitations due to routing optimization challenges among interconnected grids.
The evolving market design reflects these changes, with day-ahead markets adapting pricing structures that account for midday saturation from solar generation while intraday trading becomes more prevalent as participants seek opportunities based on forecasted peaks versus actual demand levels. Emerging balancing markets offer new revenue streams for flexible assets that can respond effectively during rapid transitions between supply levels.
Batteries are becoming increasingly integral within capital expenditure planning, with utility-scale storage systems being prioritized across Bulgaria, Greece, and Romania to capture excess midday PV generation for later use during peak periods. Such systems help mitigate curtailment risks while stabilizing market prices amidst rising penetration levels beyond five to seven gigawatts of PV capacity.
The ongoing transition emphasizes that success within this evolving landscape depends not solely on volume but also on timing and flexibility management capabilities regarding renewable integration into existing frameworks. As countries enhance their reliance on solar power by reducing imports while boosting exports during optimal conditions—investors who embrace both renewable technologies alongside flexible response mechanisms will likely gain competitive advantages leading up through the next decade until at least2030.
