The transformation of the Western Balkans electricity system is entering a decisive decade. Renewable energy capacity is expanding rapidly across the region as governments pursue decarbonization strategies and investors capitalize on falling technology costs. At the same time the gradual decline of coal-fired power generation is reshaping the operational dynamics of the power system. Between 2026 and 2035, the central challenge will not be the construction of renewable capacity itself but the availability of flexibility resources capable of balancing variable generation.
Flexibility refers to the ability of a power system to adjust generation or demand quickly in response to changes in electricity supply. Wind and solar generation fluctuate according to weather conditions, meaning that electricity production can rise or fall rapidly. Without sufficient flexibility resources, these fluctuations can create imbalances between supply and demand, threatening system stability.
Historically the Western Balkans relied on coal-fired power plants to provide flexibility. Although these plants were primarily designed for baseload generation, their large synchronous turbines and controllable output allowed operators to adjust generation levels when necessary. As renewable penetration increases and coal plants gradually reduce output, the system loses a significant portion of its traditional flexibility.
The scale of renewable expansion illustrates the magnitude of the challenge. Across Southeast Europe the combined pipeline of wind and solar projects exceeds 30 GW, with a substantial portion located in or near the Western Balkans. Serbia’s renewable strategy alone envisions several gigawatts of additional capacity by the end of the decade, while neighboring countries are pursuing similar goals.
Variable renewable generation introduces new operational patterns into electricity markets. Solar output peaks during midday hours, while wind production can fluctuate significantly depending on weather conditions. These patterns create large swings in electricity supply that must be balanced by flexible resources capable of ramping up or down quickly.
Battery storage systems are widely viewed as one of the most effective solutions to this challenge. Batteries can respond almost instantaneously to changes in electricity supply and demand, making them ideal for frequency stabilization and short-term balancing. The cost of lithium-ion batteries has declined dramatically over the past decade, enabling large-scale deployment in electricity markets worldwide.
In Southeast Europe battery storage deployment is still at an early stage but is expected to accelerate rapidly. Several countries are developing regulatory frameworks that allow storage assets to participate in electricity markets and provide balancing services. As these frameworks mature, battery projects are likely to proliferate alongside new renewable installations.
Pumped hydro storage represents another critical component of the flexibility portfolio. Unlike batteries, which typically provide storage durations of a few hours, pumped hydro facilities can store electricity for extended periods. This capability allows them to manage multi-hour or multi-day fluctuations in renewable generation.
The Western Balkans possess significant potential for pumped hydro development due to their mountainous geography and existing hydropower infrastructure. Serbia’s Bistrica pumped storage project, with an expected capacity of approximately 600 MW, exemplifies the type of infrastructure required to support renewable integration at scale. Similar projects have been proposed in other parts of the region.
Hydropower itself also provides valuable flexibility. Albania’s electricity system, which relies heavily on hydropower plants along the Drin River cascade, can adjust output relatively quickly in response to regional electricity market conditions. This flexibility allows Albania to export electricity during periods of high prices and import power when renewable output elsewhere is abundant.
Demand-side flexibility is another underutilized resource in the region. Industrial consumers with flexible electricity demand can adjust production schedules in response to price signals, reducing stress on the grid during peak demand periods. As electricity markets become more sophisticated, demand response programs may play an increasingly important role in balancing the system.
Cross-border electricity trading also contributes to system flexibility. The interconnected nature of Southeast European electricity markets allows countries to import electricity when domestic generation is insufficient and export surplus power during periods of high renewable production. However, this mechanism depends on the availability of transmission capacity and coordinated market operations.
The concept of the “flexibility gap” therefore describes the difference between the flexibility resources currently available in the system and those required to integrate projected renewable capacity. Analysts estimate that Southeast Europe may need several gigawatts of additional storage and flexible generation capacity by 2030 to maintain reliable electricity system operations.
Bridging this gap requires coordinated investment across multiple sectors. Transmission infrastructure must expand to accommodate new renewable generation and facilitate cross-border electricity flows. Storage technologies must scale up to provide balancing services. Market design reforms must enable flexible assets to monetize their capabilities through balancing and ancillary services markets.
The evolution of electricity markets will play a crucial role in this process. As renewable penetration increases, energy prices alone may not provide sufficient revenue to support flexible generation assets. Capacity mechanisms, ancillary services markets, and long-term contracts may be required to ensure adequate investment in flexibility resources.
For investors the flexibility gap represents both a challenge and a commercial opportunity. Projects that combine renewable generation with storage or flexible operation may enjoy competitive advantages in electricity markets characterized by price volatility and curtailment risk. Utilities and infrastructure funds are increasingly exploring such hybrid projects as part of their renewable investment strategies.
Between 2026 and 2035, the Western Balkans electricity system will therefore undergo a profound transformation. The region’s energy transition will move beyond the construction of renewable capacity toward the development of a fully integrated and flexible electricity system capable of managing the variability of wind and solar generation. Storage technologies, flexible hydropower assets, demand response programs, and cross-border market integration will form the backbone of this new energy landscape.
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