Greece’s power system is under increased strain as a prolonged heatwave drives electricity demand sharply higher, with air conditioning loads pushing the grid toward seasonal peaks.
Since the onset of the heatwave, peak demand has risen from typical summer levels of 6,000–6,500 MW to around 9,000 MW, forcing nearly all available dispatchable generation units to remain in operation to maintain system stability.
Natural gas-fired plants have been running continuously since 24 June, while PPC’s lignite unit Ptolemaida V has also been activated, particularly during evening hours when solar output drops and the system must rely on flexible thermal generation to meet demand. The situation underscores the ongoing challenge of balancing a grid that is increasingly dominated by solar generation during the day but still dependent on conventional plants during peak and ramping periods.
As photovoltaic production declines after sunset, wind generation becomes a critical balancing factor. Strong wind output reduces the need for gas and lignite plants, while weaker conditions increase their operational role in covering the evening demand gap. This interaction highlights the growing importance of weather variability in shaping short-term system stability.
The heatwave affecting much of Europe has also reinforced the need for sufficient reserve capacity. Greece’s transmission system operator ADMIE has stated that available generation is adequate even if peak demand approaches 10,000 MW, suggesting that the system remains secure under current stress conditions.
Nearly the entire gas-fired fleet is expected to remain online throughout the summer, with only one unit currently offline due to technical maintenance. ADMIE has also reportedly requested that PPC keep the lignite plant Ptolemaida V available at least through the end of the 2026/27 winter season, reflecting continued reliance on dispatchable thermal capacity.
Hydropower is providing additional system flexibility. Reservoir levels at PPC facilities are estimated to be 20–25% higher than last year, offering a stronger buffer for peak demand periods and improving the system’s ability to respond to short-term fluctuations in both demand and renewable output.
