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This analysis covers electricity generation across the entire country and is based on the latest available monthly data from the Independent Power Transmission Operator (IPTO – ADMIE) for the interconnected system (September 2026) and the Hellenic Electricity Distribution Network Operator (HEDNO – DEDDIE) for the non-interconnected islands (August 2026).It also draws on HEDNO data on low- and medium-voltage electricity generation, as well as on the installed capacity of self-generation systems (April 2026).To obtain a more accurate estimate of electricity generation from high-efficiency cogeneration (HECHP) at low and medium voltage, as well as the photovoltaic capacity factors required to estimate self-generation, the analysis uses the latest data available from the Renewable Energy Sources (RES) Special Account bulletin published by the Renewable Energy Sources and Guarantees of Origin Operator (DAPEEP) (June 2026).Wholesale electricity prices are based on Day-Ahead Market (DAM) price data from the European Network of Transmission System Operators for Electricity (ENTSO-E). A more detailed description of the methodology followed is available here.
September
Renewable energy sources (RES), primarily wind and solar power, including self-generation, recorded a significant decline in September 2026, generating 2,777.6 GWh, down 16.8% from the record-high monthly RES generation recorded in August. Nevertheless, September’s RES generation was 14% higher than in the same month last year.
Fossil gas ranked second, with generation reaching 1,554 GWh, marking a significant decline of 30.8% compared with the previous month and 12.8% compared with September 2025.
Large hydropower ranked third, generating 336.8 GWh, down 31.3% compared with August. However, generation was up 18.4% compared with September last year.
Oil-fired generation on the non-interconnected islands followed, amounting to 240 GWh, down 21.8% compared with August and 32.6% compared with September 2025, thanks to the completion of Crete’s new electricity interconnection.
Lignite ranked last, with generation totalling 228.2 GWh, exclusively from the Ptolemaida V power plant. This was slightly lower (-7%) than in August, but more than double (+120%) the level recorded in September 2025, when lignite-fired generation stood at just 103.7 GWh.
Finally, large-scale battery storage systems absorbed a total of 55.7 GWh and discharged 47.9 GWh into the grid, representing increases of 11.2% and 10.5%, respectively, compared with the previous month.
Total domestic electricity demand in September reached 4,765 GWh, down 19.3% compared with August, but slightly higher (+1.4%) than in September 2025. Total domestic electricity generation followed a similar trend, reaching 5,186 GWh, down 22.3% compared with August but up 4.5% compared with September 2025.
Regarding the country’s electricity interconnection balance, Greece recorded net exports of 421.5 GWh, down 45.2% compared with August but up 58% year-on-year.
The average wholesale electricity price (Day-Ahead Market) reached €156.3/MWh, its highest level since January 2023, marking a 17.2% increase compared with the August average. This was driven by increased gas-fired generation, combined with higher gas procurement prices. Specifically, the average monthly TTF price for front-month contracts reached a new annual high in September, at €61.6/MWh, up 15.5% from the previous month’s level of €53.3/MWh. The September 2026 price was the highest in the past three and a half years, following the €64.5/MWh recorded in February 2023.
First nine months of the year
Cumulatively, over the first nine months of 2026, RES maintained their leading position, generating 24,303 GWh and setting a new record for electricity generation during this period of the year.
Fossil gas retained second place, with generation reaching 16,677 GWh, just 3% below the historical high of 17,192 GWh recorded during the first nine months of 2025.
Large hydropower ranked third, generating 5,028 GWh, the highest output for this period of the year since 2013.
Lignite followed, with generation totalling 2,058 GWh, representing a clear increase (+7.4%) compared with the record low recorded during the same period in 2025.
Oil-fired generation, however, reached a record low for this period of the year, at 1,812 GWh, down 38.4% compared with the first nine months of 2025.
Electricity discharged into the grid by battery storage systems reached a cumulative total of 148.5 GWh, six months after the first battery storage system became operational.
Domestic electricity demand during the first nine months of 2026 stood at 43,366 GWh, representing a slight decrease (-0.43%) compared with the same period in 2025. By contrast, domestic electricity generation exceeded 50 TWh, reaching 50,039 GWh, an increase of 10.6% compared with the corresponding period in 2025.
The difference between domestic electricity demand and generation is attributable to the country’s net-exporting electricity interconnection balance, which reached a record 6,673 GWh during the first nine months of 2026. This was more than double the total net exports recorded over the whole of 2025 (3,010 GWh).
Changes in Energy Sources Covering Electricity Demand
Comparing the first nine months of 2026 with the same period in 2025, net exports recorded a sharp surge (+4,987 GWh). This increase was more than offset by higher domestic electricity generation, primarily from RES (+3,620 GWh) and, to a lesser extent, large hydropower (+2,538 GWh). These increases, together with the contribution of battery storage (+149 GWh) and a slight decline in domestic electricity demand (-184 GWh), also compensated for the reduction in generation from oil (-1,130 GWh) and natural gas (-515 GWh).
As regards RES, the increase recorded during the first nine months of the year appears to have been driven primarily by solar photovoltaics and, secondarily, by wind power. Data for the high-voltage system show that solar PV generation increased by 45.6% compared with 2025, reaching 5,190 GWh, while wind generation recorded a more moderate year-on-year increase of 19.2%, reaching 8,931 GWh.
The corresponding percentage changes for the first nine months of 2026, compared with the same period in 2025, were as follows:
Lignite: +7.4%
Fossil gas: -3.0%
Oil: -38.4%
Renewable energy sources (RES): +17.5%
Large hydropower: +101.9%
Net exports: +295.7%
Domestic electricity demand: -0.4%
Clean Energy vs Fossil Fuels
Cumulatively, over the first nine months of 2026, clean energy sources (wind, solar PV, self-generation, biomass and hydropower) reached a new all-time high, with total generation amounting to 29,332 GWh, up 26.6% compared with the same period last year. Total generation from fossil fuels (lignite, natural gas and oil) stood at 20,546 GWh, down 6.8% compared with the same period in 2025, mainly due to the decline in oil-fired generation and, to a lesser extent, natural gas-fired generation. As a result, the gap between clean energy sources and fossil fuels widened to 8,785 GWh, marking the largest-ever difference in favour of clean energy sources. During the first nine months of the year, clean energy sources accounted for 67.6% of domestic electricity demand and 58.6% of total domestic electricity generation.
RES Curtailments
Based on the combination of forecasts included in IPTO’s ISP2 and ISP3 dispatch solutions, renewable energy curtailments in September are estimated at 158.2 GWh (or 5.4% of total RES generation). This was virtually unchanged from August (158.6 GWh) and slightly lower than the curtailments recorded in September 2025 (169.5 GWh).
Cumulatively, during the first nine months of 2026, curtailments reached 2,063 GWh (or 7.8% of total RES generation), surpassing the 2 TWh threshold. This was 15.6% higher than the curtailments recorded during the first nine months of 2025 (1,786 GWh), and also exceeded total lignite-fired electricity generation over the same period in 2026 (2,058 GWh). The highest daily curtailments during the month were recorded on 27 September, reaching 29.8 GWh.
Battery Storage
New records were set in September 2026 for the contribution of battery storage systems to preventing renewable energy curtailments and reducing natural gas use. An additional 48 MW of storage capacity was also brought into the system, bringing total installed charging capacity to 700 MW[1].
According to the ISP2 and ISP3 forecasts included in IPTO’s respective dispatch solutions, in September, batteries absorbed 56.4 GWh and discharged 48.9 GWh into the grid[2]. The same forecasts indicate that 18.5 GWh were absorbed during hours when no RES curtailments were taking place. Given that total renewable energy curtailments in September amounted to 158.2 GWh, the installed battery capacity prevented 19.3% of potential RES curtailments, by absorbing 37.9 GWh that would otherwise have been curtailed. Meanwhile, natural gas use was reduced by 48.9 GWh as a result of electricity discharged from batteries during evening hours.
Cumulatively, from April 2026, when the first battery storage systems became operational, through September, batteries absorbed a total of 178.2 GWh, of which 62 GWh during hours without RES curtailments, while discharging 155.2 GWh into the grid. As a result, they prevented 5.3% of total RES curtailments over this period. Despite the continued progress observed since July, the data highlight the need to accelerate the deployment of energy storage systems.
Hours with near zero or negative prices
n September 2026, 106.5 hours of near-zero or negative prices [3]were recorded in the wholesale electricity market. This was 14.25 hours more than in the previous month and 30.5 hours more than in September 2025.
Cumulatively, 1,055.5 hours of near-zero or negative prices were recorded during the first nine months of 2026, 2.7 times the 390 hours recorded over the same period in 2025.
[1] This capacity figure also includes two PPC battery storage systems with a combined capacity of 98 MW. Although they were incorporated into IPTO’s day-ahead scheduling process in July, they had not contributed to the system by the end of September.
[2] According to IPTO’s monthly bulletin for September, batteries absorbed 55.3 GWh and discharged 47.9 GWh into the grid. These figures are broadly in line with the corresponding values from IPTO’s daily ISP2 and ISP3 dispatch solutions (56.4 GWh and 48.9 GWh, respectively).
[3] DAM prices less than or equal to €0.05/MWh.
