Solar-led renewable growth lifts South-East Europe output, but wind variability keeps prices and balancing tight

Renewable energy output across South-East Europe increased sharply during calendar week 13, but the details of that growth point to a power system that is still struggling to manage intermittency and uneven resource distribution. While solar is increasingly shaping daytime supply and pricing, wind variability continues to limit how much the region can smooth overall generation and balance.

Renewables up across the region, led by solar

Total renewable generation climbed 12.2% to 3,914.7 GWh. Solar provided the dominant contribution: output rose 27.7%, supported by longer daylight hours and improving seasonal conditions. The report notes that this translated into a measurable effect on daytime pricing, particularly in markets with higher solar penetration.

Wind growth remains modest and uneven

Wind generation increased only 4.1%, highlighting persistent variability in wind resources across the region. In several markets, weaker wind conditions reduced the extent to which renewable growth translated into improved system balance.

Country highlights: Italy surges; Hungary and Serbia follow

Italy recorded the most pronounced rise, with total renewable output increasing by 205.1%. The increase was driven by strong performance in both wind and solar and helped reduce reliance on thermal generation during the week, although Italy remained structurally import-dependent.

Hungary and Serbia also saw substantial gains, though from lower baselines. Hungary’s increase was linked to a spike in solar generation, while Serbia’s renewables doubled primarily due to higher wind output.

Declines in Romania, Türkiye and Greece show the limits of diversification

The regional picture remains highly uneven. Romania and Türkiye both experienced declines in renewable output, largely attributed to weaker wind conditions. Greece also saw a net reduction in renewables as a significant drop in wind outweighed gains from solar.

Implications for price formation and flexibility needs

The data underscores a key challenge for SEE markets: even as renewable capacity expands, its contribution to system stability remains inconsistent. Solar generation tends to be more predictable during daylight hours, but continued wind variability introduces uncertainty into supply balances.

This dynamic affects price formation. When solar output is strong, daytime prices can soften; however, because wind is not consistently available to extend low-cost supply into later hours, evening peak prices remain elevated—especially when gas-fired generation sets the marginal price.

With solar playing a larger role, flexibility assets are becoming more important. The report points to battery storage and demand response mechanisms as critical tools as intraday price spreads are expected to widen with higher solar penetration—supporting arbitrage opportunities while also increasing operational complexity for system operators.