The Southeast European power market is entering a new investment cycle following one focused mainly on adding renewable capacity. The next phase is expected to centre on flexibility, including batteries, hydro optimisation, pumped storage, interconnectors, balancing markets, digital forecasting and demand-side response. Week 23 captured the shift in operating conditions across the region.
In Week 23, regional demand increased by 8.2%. Variable renewables declined by 8.9%, with wind down 15.5%. Thermal generation rose by 24.5%, hydro increased by 10.1%, and imports climbed by 9.1%.
Week 23 as a flexibility stress test
The changes in demand and generation were not limited to a single supply shortage or a renewable-driven outcome. The balance of hydro output, thermal generation and cross-border flows supported system coverage during the period. The same combination also highlighted limits of relying on existing balancing patterns as the system evolves.
Thermal generation introduces carbon and fuel-price exposure. Hydro output depends on hydrology conditions. Cross-border imports depend on neighbouring availability and the capacity of interconnectors connecting markets.
Batteries for intraday balancing and ancillary services
Batteries are described as the most immediate flexibility option for the region’s next cycle. The evening price ramp supports a storage business case that can charge during lower-price solar hours and discharge during peak periods.
Two-hour and four-hour battery systems are positioned to support arbitrage, balancing and ancillary services. Co-located battery energy storage systems can also improve the bankability of solar and wind projects.
Pumped storage and long development horizons
Pumped storage is identified as the long-duration layer within the flexibility portfolio. The region’s hydro geography provides natural potential for such projects, but development timelines are long.
Pumped storage projects require permitting, grid coordination and public-private financing structures. As solar penetration increases, long-duration storage is expected to become more valuable.
Interconnectors and market efficiency across SEE
Interconnectors are another investment theme linked to persistent cross-border price differences. Ongoing spreads are cited between Italy, Greece, Hungary, Romania, Serbia, Bulgaria and Croatia.
The constraints behind these spreads are described as limiting market efficiency. Additional cross-border capacity is expected to reduce price fragmentation, improve security of supply and enable monetisation of regional surplus.
Digital forecasting and balancing-market optimisation
Digital infrastructure is also highlighted as part of the flexibility build-out. Forecasting systems, SCADA integration, intraday trading platforms and balancing-market optimisation are expected to become essential components.
Flexibility is characterised as both physical and informational in this context. Forecasting wind, solar, demand and congestion is described as having direct financial value for market participants.
Investment scope beyond generation assets
The shift in operating needs expands the range of asset types expected in Southeast Europe. The next set of energy assets includes storage portfolios, flexibility platforms, grid equipment, forecasting services and balancing aggregators.
Hybrid renewable projects are also included within the forward-looking list of opportunities. Utilities and developers that act early are described as being able to capture premium margins under these conditions.
Elevated by energy.clarion.engineer