The energy transition in Southeast Europe (SEE) is characterized by a significant shift away from coal and towards renewable sources. However, this evolution is complicated by a persistent dependency on gas, driven not merely by political factors or renewable deployment challenges, but rather by the legacy of existing infrastructure. The operational frameworks established for coal generation are being adapted for gas, reinforcing its role as the primary backup technology in the region.
In SEE, the phase-out of coal does not involve an overhaul of the energy system; instead, it manifests through asset substitution within a largely unchanged operational context. For instance, ash disposal sites are being converted into solar parks, while former coal substations are transitioning to renewable energy hubs. Despite these changes appearing to signify progress, they often maintain the foundational principles of coal-era operations—such as centralized dispatch and substantial connection capacities—while relying heavily on fast-ramping thermal support.
A notable case is Serbia’s Nikola Tesla A complex in Obrenovac, where land previously used for ash disposal is being repurposed for solar energy projects. This initiative aligns with decarbonization aims and optimizes asset use. However, the underlying system architecture remains tailored to thermal output, indicating a continued reliance on gas as a controllable backup resource.
Similarly, Bulgaria’s Maritsa East 3 site, which was once home to a coal-fired power station, now features one of the largest battery energy storage systems in SEE with a capacity of 202 MW / 500 MWh. This battery utilizes the existing grid connection from the former coal plant, allowing it to participate in the market without incurring new transmission costs. While this repurposing demonstrates efficient use of infrastructure, it does not displace gas but rather enhances its utilization during peak demand periods.
The design of coal infrastructure inherently favored dispatchability over intermittency. As solar and wind energy sources are integrated into these legacy systems, they are expected to operate alongside controllable resources like gas. Other technologies such as nuclear offer baseload capacity but lack flexibility for rapid adjustments. Hydro power can provide some flexibility but is contingent upon weather conditions. Consequently, gas emerges as the only technology that fits seamlessly within this inherited operational framework.
This structural bias towards gas is further entrenched by existing grid codes and market regulations that have evolved around thermal generation. The ongoing repurposing of coal assets without comprehensive redesigns of these frameworks tends to favor gas as a default solution.
The ramifications extend beyond electricity generation; they affect maintenance schedules, reserve procurement strategies, and market balancing designs—all premised on rapid thermal response capabilities. The reduction of coal capacity creates a void that is inevitably filled by gas.
The financial landscape also plays a crucial role in sustaining this path dependency. Existing coal assets have already depreciated, making their grid connections sunk costs that can be leveraged for new projects with minimal capital outlay and regulatory hurdles. Gas plants are frequently already operational or can be accessed through imports, providing an essential layer of flexibility without necessitating new construction efforts.
Ultimately, the transition occurring in SEE should be viewed not as a straightforward shift from coal to renewables but rather as a complex evolution mediated by gas dependency. Without rethinking and redesigning system architecture around decentralization and flexible energy solutions such as long-duration storage or adaptable nuclear options, gas will likely remain entrenched within the region’s energy landscape due to structural design choices made over decades.
