Renewable energy sources (RES) took the lead in electricity generation in September 2025, with 2,464 GWh, although this represented a 16.5% decrease compared to August. Gas generation also fell to 1,719 GWh, while lignite increased (104 GWh, +39.7%). The average wholesale market price reached €92.75/MWh, up 26.8% compared to August. In the first nine months of 2025, gas generation set a record at 17,183 GWh, and exports also hit a record of 1,687 GWh. RES Curtailments reached historically high levels at 1,785 GWh for the nine-month period—more than double the amount for the same period in 2024—while lignite dropped to a historic low.
This analysis concerns electricity production across the entire territory of Greece and is based on the latest available monthly data from the Independent Power Transmission Operator (IPTO) for the interconnected grid (September 2025) and from the Hellenic Electricity Distribution Network Operator (HEDNO) for the non-interconnected islands (August 2025). In addition, we use data from HEDNO for low and medium voltage, as well as for the installed capacity of self-production systems (April 2025). Data from the Renewable Energy Special Account bulletin of the Renewable Energy Sources & Guarantees of Origin Operator (DAPEEP) (August 2025) are used to calculate more accurately CHP production at low and medium voltage, as well as for the PV utilization factors needed to estimate self-production. Finally, for the wholesale electricity market we use price data of the Day-Ahead Market from ENTSO-E. You can read in more detail about our methodology here.
The month of September
In September 2025, renewables (mainly wind and solar) ranked first in electricity production with 2,464 GWh and the highest production for the month of September in the last decade. However, compared to August 2025, they decreased by 16.5%.
Fossil gas ranked second after renewables with 1,722 GWh, continuing the downward trend that began in July. Compared to August it fell by 12.3%, while it was close to last September’s levels (1,719 GWh).
Large hydro with 283 GWh recorded a 15.3% decrease compared to August, but were 9% higher than last September.
Lignite contributed only 104 GWh but recorded an increase of 39.7% compared to August, with 89% of production coming from Agios Dimitrios III and IV. Compared to last year, lignite production decreased by 33.9% and reached its lowest historical levels for the month of September.
Total domestic demand reached 4,770 GWh, slightly higher than last September’s levels (4,618 GWh) and down 11.9% compared to August.
In terms of the interconnection balance, Greece was a net exporter for the fifth consecutive month, reaching 267 GWh in net exports. Compared to the previous month, exports decreased by 41.6% but compared to September last year they increased by 194.4%.
The average price on the wholesale energy market in September 2025 was 92.75 €/MWh, marking an increase of 26.8% compared to August, which is related to the increase in lignite and the decrease in RES in the electricity generation mix. Compared to September last year, the price was down by 17.5%.
The first nine months of the year
Comparison of sources
In the first nine months of 2025, renewables led the way in electricity production with 20,709 GWh cumulatively and a decade high, while they also increased by 8.5% since the same period last year.
Fossil gas followed with 17,183 GWh cumulatively, marking a high and an 11% increase over the first nine months of 2024.
The country’s net exports were also at an all-time high, reaching 1,687 GWh for the first nine months of 2025. In addition to the interconnection balance, which has been moving towards net exports since 2023, both RES and gas have been on an upward trend in the first nine months of the year since 2023.
Oil ranked third in electricity production after renewables and gas, with 2,999 GWh cumulatively for the nine months. This was followed by large hydro with 2,489 GWh, down 15.1% compared to the same period in 2024. Lignite came in last place with 1,916 GWh and the lowest historical electricity production for the nine-month period.
Shares of energy sources in meeting demand
Domestic electricity demand in the first nine months of 2025 reached a total of 43.622 GWh, very close to the level recorded in the same period of 2024 (43.732 GWh, -0.3%). However, domestic power generation increased by 6% in 2025 compared to 2024 (from 43.647 GWh in 2024 to 46.267 GWh in 2025) in order to meet the electricity needs of neighboring countries.
Renewables held the largest share in meeting demand with 47.5%, marking a decade-high for the first nine months of the year.
Fossil gas ranked second, covering 39.4% of demand and also reaching its highest level of the decade for this period.
Oil followed in third place after renewables and gas, covering 6.9% of total demand — and more than 90% of demand on the non-interconnected islands.
Large hydropower ranked second to last with a share of 5.7%, while lignite came last with 4.4% — the lowest contribution to demand for this time of year.
Changes in the shares of energy sources in demand coverage
Comparing January–September 2025 with the same period in 2024, the largest shifts were observed in cross-border electricity exchange, gas and renewables. Gas and renewables increased by 1.701 GWh and 1.615 GWh respectively, while the interconnections balance shifted by 2.496 GWh towards net exports.
The increase in renewables during the first nine months of the year (+1.615 GWh) is mainly due to higher solar PV generation, which offset lower wind production. Indicatively, high-voltage solar PV output during this period was 1.698 GWh higher than in 2024, while high-voltage wind generation was 281 GWh lower.
Large hydropower, lignite and oil decreased by 441 GWh, 408 GWh and 83 GWh respectively over this period.
In summary, the increase in renewables was more than sufficient to offset the drop in large hydropower, lignite and oil generation (-932 GWh in total), while part of the additional renewable output was exported to neighboring countries. However, fossil gas made an even greater contribution to net electricity exports, as the increase in gas generation (1.701 GWh) accounted for the largest share of the shift in the interconnections balance (2.496 GWh).
The corresponding percentage changes in the first nine months of 2025, compared to the same period in 2024, were:
Lignite: -17.6 %
Fossil gas: +11.0 %
Renewables: +8.5 %
Large hydro: -15.1 %
Net imports: -308.5 %
Oil: -2.7 %
Demand: -0.3 %
Comparison of clean energy with fossil fuels
In the first nine months of 2025, clean energy sources (wind, PV, hydro, biomass, self-generation) with a total production of 23,198 GWh remained in first place, surpassing fossil fuels (fossil gas, lignite, oil) which had a total production of 22,097 GWh. The difference between clean energy and fossil fuels was 1,100 GWh (slightly down from the corresponding difference of 1,136 GWh in 2024), with clean sources meeting 53.2% of total demand.
Energy curtailment from RES
Based on the combination of forecasts shown in the ISP2 and ISP3 solutions of the consolidated planning process of the IPTO, RES curtailments in September reached 169 GWh, or 6.4% of the total RES generation. Compared to September 2024, they increased by 49%, since last year’s curtailments were 114 GWh (5.97% of the corresponding monthly RES generation).
The day with the highest curtailments was Sunday September 21st 2025, with a total of 33.5 GWh. Most RES curtailments in September occurred between 11am and 2pm.
Cumulatively, in the first nine months of 2025, an estimated 1,786 GWh—or 7.9% of total RES generation—was rejected, more than double the RES curtailments during the same period in 2024 (699 GWh). Notably, the total estimated RES curtailments in the nine-month period of 2025 (1,786 GWh) approached the total lignite-based electricity generation over the same period (1,916 GWh).
