In May 2025, the carbon intensity of power generation dropped to a 10-year low (214 g CO2/kWh) thanks to the rise of renewables. However, a total of 6.34 million tons were emitted in the first five months of 2025 due to a surge in gas use. With only 3.856 million tons left in the sector’s carbon budget for the year, the country is off track to meet its 2025 NECP target. Notably, had there been no RES curtailments during the first five months (975 GWh), the power sector would have emitted 0.54 million tons less, more than the total emissions from Ptolemaida 5 in the same period (0.44 million tons).
Monthly emissions from each power plant in Greece are estimated based on the latest available electricity production data (May 2025 for the interconnected network and March 2025 for the non-interconnected islands) and the annual CO2 emissions from ETS (2024), following the methodology and assumptions presented here.
In May 2025, carbon intensity[1] fell to 214 g CO2/kWh, down 10% from April 2025, and the lowest monthly level in at least a decade. This is primarily due to the increase in total power generation and the dominant position of renewables in generating electricity. Despite the record May, the average annual carbon intensity for the first five months of 2025 (276.4 g CO2/kWh) increased from 2024 (271 g CO2/kWh) due to the surge in gas-fired electricity generation in 2025.
The impact of renewable energy curtailments on emissions is significant. According to daily forecasts by the IPTO, RES curtailments reached 975 MWh, in the first five months of 2025. Without these cuts, emissions from fossil fuel power plants would have been 5.8 million tons, 8.5% lower than actual levels, while the corresponding carbon intensity of the power sector would have been reduced by 23.4 g CO2/kWh, lower than actual (253 g CO2/kWh).
In May 2025, carbon emissions from fossil fuel-fired power plants were 0.96 million tons, an increase of 9% compared to April 2025. The modest recovery of gas-fired power generation close to March levels was the main reason for the increase in emissions.
In the first five months of 2025, emissions totaled 6.34 million tons, the highest level for this period in the past three years. This consistent upward trend since the start of 2025 is mainly driven by a sharp rise in fossil gas use for power generation. More specifically, emissions from fossil gas power plants reached 3.35 million tons for the first five months, accounting for 53% of all power sector emissions. This represents a 22% increase compared to the same period in 2024, reaching the highest level in at least a decade.
Emissions from lignite power plants totaled 0.116 million tons in May and 1.85 million tons cumulatively for the first five months of 2025. May emissions from lignite units were the lowest in the last 7 months, thanks to historically low levels of plant operation since the beginning of the year. Specifically, lignite power production was zero for 455 hours in May (61% of the monthly total hours).
Emissions from oil-fired power plants in non-interconnected islands were estimated at 0.25 million tons for May and 0.98 million tons for the first five months of 2025, remaining close to 2024 levels for the same period (0.97 million tons).
In terms of the breakdown of emissions per power plant, the top five largest polluters of the first five months of 2025 remain the same, with minor changes in ranking.
The Agios Dimitrios lignite power plant remained the largest single emitter, with 1.4 million tons of emissions in the first five months of 2025. Despite its relatively small role in meeting demand, the Agios Dimitrios power plant accounted for 22% of the power sector’s cumulative emissions during this period.
Megalopolis V came in second place with emissions of 0.51 million tons for the first five months of 2025, recording a 21% increase compared to the same period in 2024. Lavrio IV-V ranked third with emissions of 0.44 million tons, moving up from fifth place.
In fourth and fifth place among the largest polluters were Ptolemaida 5 and Agios Nikolaos II, with emissions of 0.422 and 0.417 million tons, respectively.
On the non-interconnected islands, the five largest polluters were responsible for 68% of total emissions from all oil-fired power plants in the first five months of 2025. Atherinolakos and Linoperamata topped the list, with emissions of 0.24 and 0.174 million tons, respectively. They were followed by the Rhodes plant (0.089 million tons), the Chania plant (0.084 million tons), and the South Rhodes (0.078 million tons).
According to the revised National Energy and Climate Plan (NECP) submitted in January 2025 to the European Commission, emissions in the electricity sector are expected to decrease significantly in the coming years. In particular, the target for 2030 is a maximum of 4 million tons of emissions from all three fuels (lignite, fossil gas, oil). This marks a substantial decrease (-91%) compared to 2013, the year in which thermal power plants first began paying for their carbon emissions under the Emissions Trading System (ETS).
In the final NECP, the estimated emissions for 2025 are 10.2 million tons, 5.573 million tons, less than in 2024 (15.77 million tons[2]). In the five months of 2025, a total of 6.34 million tons are estimated to have been emitted from the power generation sector. This represents 62.2% of the available carbon budget for the whole year. With 3,856 million tons remaining in the sector’s carbon budget for the year, the country is off track to meet its 2025 NECP target.
You can explore how electricity sector emissions evolved since 2013, as well as find analyses from previous months here.
[1] Carbon intensity is defined as the ratio of emissions from the three fuels (lignite, gas and oil, including CHP) to the country’s total electricity production from the interconnected grid and the non-interconnected islands.
[2] The 2024 emissions are the estimated emissions based on the assumptions reported here