975 GWh of RES were rejected cumulatively in the first 5 months of 2025 (383 GWh in May), exceeding the total curtailments for the entire year of 2024 (899 GWh). Despite these high curtailments, RES production in May reached 2,219 GWh. This brought the average price on the energy market down to 81.9 €/MWh – the lowest in the past 12 months. Gas-fired generation ranked second, with a moderate rebound to March levels (1,457 GWh), while the interconnection balance returned to net exports after March, totaling 139.7 GWh.
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 (May 2025) and from the Hellenic Electricity Distribution Network Operator (HEDNO) for the non-interconnected islands (March 2025). In addition, we use the most recent 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) (April 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 hourly price data of the Day-Ahead Market from ENTSO-E. You can read in more detail about our methodology here.
The month of May
In May 2025, renewables (mainly wind and solar) increased by 13.8% compared to April and remained in the first place of electricity production with 2,219 GWh.
Fossil gas interrupted the downward trend of the last two months and instead increased by 33.5% this month compared to last month, reaching 1,457 GWh and at levels similar to March.
Lignite at 78.7 GWh had the lowest monthly electricity generation for 2025 and for the last seven months, as the previous lowest was in October 2024 at 65.1 GWh.
Large hydro increased by 32.8% from April, reaching 257 GWh and the second highest value for 2025 after January.
Total domestic demand increased by 3.8% month-on-month ending at 4,204 GWh.
In terms of the interconnection balance, Greece returned to a net export position in May, with net exports totaling 139.7 GWh. From October 2024 to date, the country recorded net exports every month except April 2025, when it recorded net imports of 433 GWh.
The average price on the wholesale market continued the downward trend that started in March, and at 81.9 €/MWh it was the lowest since May 2024. It was also down by 8% compared to April 2025.
The first five months of the year
Comparison of sources
The increase in RES generation in May placed renewables at the top of the electricity mix. With a total of 9,935 GWh cumulatively for the first five months of 2025, RES surpassed fossil gas. However, RES still marked a slight decrease compared to the same period in 2024 (10,070 GWh).
Nonetheless, at 8,874 GWh, fossil gas once again recorded a decade high for electricity generation in the first five months of the year.
Alongside this increase in the first five months of 2025, Greece was a net exporter of electricity with 565 GWh, a high for at least the last decade.
Lignite, with production of 1,347 GWh, was in third place and at levels similar to 2024 for the same period. Oil followed with 1,257 GWh and similarly close to the levels of the first five months of 2024. Large hydro was in last place with 1,112 GWh.
Shares of sources in meeting demand
Electricity demand in the first five months of 2025 was 21,966 GWh.
Renewables maintained the lead in meeting demand with a 45.2% share, and the second highest share after 2024.
The share of fossil gas in meeting demand continued the downward trend that started in March, covering 40.4% and second only to renewables.
Lignite ranked third with a 6.1% share, similar to the same period last year, followed by oil with a 5.7% share to meet demand on non-interconnected islands.
Large hydro was last in the ranking of sources, meeting just 5.1% of demand within the five-month period. This is due to reduced electricity generation in the first months of 2025.
Changes in the sources of demand coverage
Comparing the first five months of 2025 with the same period in 2024, the most notable changes were seen in gas-fired generation, interconnection balance, demand and large hydro.
Fossil gas had the largest change of all sources, increasing by +1,756 GWh. Over the same period, net exports increased by +768 GWh, with the key change being a transition from net imports of 203 GWh in the first five months of 2024 to net exports of 565 GWh in the first five months of 2025. In the same period, demand increased by +618 GWh, while renewables and large hydro recorded a decrease of -135 GWh and -312 GWh, respectively. Lignite and oil had a combined increase of +78 GWh.
Therefore, the large increase in fossil gas in the first five months of 2025 (+1,756 GWh) covered primarily the increase in net exports (+768 GWh) and demand (+618 GWh) and secondarily the reduced production from RES (-135 GWh) and large hydro (-312 GWh).
The corresponding percentage changes in the first five months of 2025, compared to the same period in 2024, were:
Lignite: +3.0 %
Fossil gas: +24.7 %
Renewables: -1.3 %
Large hydro: -21.9 %
Net imports: -378.7 %
Oil: +3.2 %
Demand: +2.9 %
Comparison of clean energy with fossil fuels
In the first five months of 2025, production from fossil fuels (fossil gas, lignite, oil) exceeded production from clean sources (wind, PV, hydro, biomass, self-generation), but the difference between them decreased significantly.
In particular, fossil fuels recorded a total production of 11,477 GWh for the first five months of 2025, covering 52% of demand (21,966 GWh). Similarly, clean sources produced a cumulative 11,047 GWh for the five months, just 4% less than fossil fuels.
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 May reached 383 GWh. This means that 14.7% of the May 2025 RES generation was rejected. In comparison, the corresponding May 2024 curtailments were only 127 GWh, accounting for6% of the respective monthly RES generation.
Most RES curtailments in May occurred between 9am and 6pm, while the day with the highest curtailments was May 1st, 2025, with a total of 54 GWh.
Cumulatively, in the first five months of 2025, 975 GWh or 8.9% of total RES generation was rejected. This is more than double the RES curtailments of the same period of 2024 (454 GWh) and more than the curtailments of the entire year of 2024 (899 GWh).