As of the first quarter of 2026, wind and solar energy have evolved from mere growth sectors to pivotal forces in shaping the dynamics of South-East European (SEE) power markets. This transformation is underscored by a notable increase in renewable energy output, which rose by 21.7% week-on-week, largely driven by a remarkable 74.6% surge in wind generation. Conversely, solar output saw a decline of 9.4%, highlighting an emerging asymmetry that contributes to market volatility.
This trend is part of a larger continental shift, where wind and solar have gained significant traction following a record year in 2025, when they surpassed fossil fuel generation for the first time within the EU. The implications for intraday pricing and flexible generation economics are profound, indicating that this transition is not merely a temporary fluctuation but a fundamental change in the energy landscape.
Within SEE, the renewable energy landscape remains uneven compared to north-western Europe. Greece has made substantial progress, integrating a larger share of renewables into its market behavior. Romania’s energy system is heavily influenced by wind variability, particularly under conditions where hydro resources are constrained. Meanwhile, Bulgaria and Croatia are increasingly navigating the complexities of intermittent generation alongside cross-border trade. Serbia is at an earlier stage in this transition but has developed a significant pipeline that positions wind and solar as central to future price-setting mechanisms.
Currently, Serbia boasts approximately 3,709.5 MW of installed renewable capacity, including 824.2 MW from 13 operational wind farms. The country’s solar sector is also on an upward trajectory, evolving from minimal historical capacity to a burgeoning multi-gigawatt project pipeline.
The distinct impacts of wind and solar on market dynamics cannot be overlooked. Wind is becoming the primary driver of both positive and negative fluctuations in weekly generation patterns across SEE. For instance, Türkiye experienced a staggering 70% increase in renewable output predominantly due to wind energy, while Greece saw its wind generation more than double. In contrast, Romania and Hungary faced significant declines in wind production that tightened local supply and elevated prices.
Solar energy presents a different challenge; while it does not fluctuate as dramatically week-to-week, it exerts substantial downward pressure on daytime prices during peak seasons. However, this growth in solar capacity is outpacing the development of necessary flexibility measures within the market. This imbalance could lead to increased midday price compression and heightened risks of curtailment in certain areas, necessitating reliance on gas imports or coal where available.
The implications of these changes were evident during Week 16 of 2026 when gas prices fell sharply yet power prices increased across much of SEE due to variability in renewable and hydro outputs rather than fuel costs alone. As wind surged and hydro generation declined by 3.45%, thermal plants were compelled to adjust their operations accordingly. This scenario illustrates that renewable output has transitioned from being an ancillary component to becoming the primary influence on overall market behavior.
The overarching trend for Q1 2026 indicates a shift from merely increasing capacity towards enhancing system flexibility. The pressing question for stakeholders now revolves around whether the existing infrastructure can accommodate the next wave of renewable integration without exacerbating market instability.
Looking ahead through the remainder of 2026, forecasts suggest continued growth in renewable generation volumes across SEE, particularly in Greece, Romania, and Serbia’s developing projects. Average annual power prices are expected to gradually decrease from their crisis-era peaks while remaining subject to volatility throughout daily trading periods. In this context, midday solar pressure will likely intensify during spring and summer months.
Conversely, scenarios characterized by tighter systems reveal that inadequate flexibility could become a critical concern. In such cases, additional renewable megawatts may not alleviate scarcity pricing; instead, they could amplify intraday volatility and lead to abrupt price spikes when wind or solar output diminishes or when cross-border imports tighten.
For utilities and energy companies operating within this landscape, it is evident that wind and solar assets are no longer standalone generators but integral components reshaping adjacent asset classes. Gas plants are gaining importance as flexible responders while cross-border capacities serve as crucial volatility mitigators. Hydro resources are increasingly valued for their dispatchable capabilities, and battery storage emerges as an essential link between low-cost renewable growth and sustainable market structures.
Battery Storage: A Key Component for Stability
Battery storage has emerged as a vital element in ensuring that the growth of wind and solar translates into stable market conditions within SEE. By Q1 2026, battery technology has transitioned from experimental phases into mainstream applications across various European markets.
In 2025 alone, the EU added approximately 27.1 GWh of battery storage capacity, marking significant progress toward maturity within this sector. This development is particularly relevant for SEE as it faces rising renewable penetration coupled with sharp intraday price fluctuations and increasing demand for fast-response balancing services.
The recent report from Week 16 exemplifies the critical role batteries could play in stabilizing markets; with wind generation surging by 74.6% while solar output fell by 9.4%, reliance on thermal plants became necessary to maintain balance amidst shifting cross-border flows and rising prices across most markets despite lower gas costs.
The case for battery investment within SEE hinges on their ability to provide immediate value through functions such as time-shifting solar production, smoothing out wind variability impacts, supporting ancillary services, reducing balancing costs, and enhancing revenue stability for renewable portfolios.
Romania currently leads in storage advancements with multiple gigawatt-scale battery energy storage system (BESS) projects underway backed by key players like Enery and Mass Group among others. Notable developments include a planned 200 MW / 400 MWh battery project near Iași aimed at addressing high renewable volatility challenges while improving grid reliability.
Greece follows closely behind with significant policy support facilitating major standalone storage projects aimed at mitigating curtailment risks associated with its growing renewable portfolio. A notable example includes a planned 330 MW / 790 MWh facility targeting completion by Q2 2026.
Serbia is beginning its journey into battery integration with initial projects emerging alongside its expanding solar capacity; however, these developments remain focused more on project-level integration rather than widespread deployment at this stage.
The outlook for battery storage deployment through late 2026 suggests acceleration but lacks uniformity across regions; Romania and Greece are expected to continue leading while Serbia gradually adds hybrid solutions into its mix alongside selective movements from Bulgaria and Croatia based on economic feasibility assessments.
In summary, the discussion surrounding battery technology transcends mere technological advancement; it fundamentally addresses how markets can effectively integrate renewables while maintaining stability amid increasing volatility challenges posed by rapid growth in both wind and solar capacities across South-East Europe.
