The carbon intensity of electricity generation reached a historic low in May 2026 (200 g CO2/kWh), as it also did for 2026 as a whole (227 g CO2/kWh), thanks to record-breaking generation from renewables and hydropower during the first five months. Without the significant curtailments of renewables during this period (1.3 TWh), the average carbon intensity would have been 14.2% lower and below 200 g CO2/kWh. The Agios Dimitrios lignite-fired power plant emitted 0.11 million metric tons during its final month of operation and 1.58 million metric tons over the five-month period, remaining the top polluter.
Monthly emissions from each power plant in Greece (that is subject to ETS reporting) are estimated based on the latest available electricity production data (May 2026 for the interconnected network and April 2026 for non-interconnected islands) and the annual CO2 emissions from ETS (2025), following the methodology and assumptions presented here.
Carbon intensity of electricity production
In May 2026, the carbon intensity of electricity production fell to a year-low and a historic low of 200.1 g CO2/kWh, thanks to high electricity production from renewables and hydropower. Compared to April, the carbon intensity decreased by 10.6%, while compared to May of last year, it decreased by 9.6%. The previous all-time low for carbon intensity was in October 2024 (216 g CO2/kWh), when lignite-based generation was the second lowest on record (65 GWh).
For the first five months of 2026, the average carbon intensity stood at 227 g CO2/kWh, down 15.6% compared to 2025 and a new annual record low. This is primarily due to record-high electricity generation from renewables and large hydro plants, combined with historically low electricity generation from lignite.
Based on IPTO’s ISP2 and ISP3 forecasts, RES curtailments for the first five months of 2026 are projected at 1,303 GWh, or 9.9% of total renewable energy generation. If the curtailed energy had been stored in batteries and used to reduce electricity generation from fossil gas and lignite, then the average carbon intensity would have been 194.7 g CO2/kWh, which is 14.2% lower than the actual figure.
Emissions per fuel
In May 2026, CO2 emissions from power plants using fossil fuels reached 1 million metric tons, up 6.7% from April but the second lowest of the year after those in April.
Cumulatively for the first five months of the year, emissions in 2026 reached 5.9 million metric tons, down 7.9% compared to the first five months of 2025, though they were 4.5% higher than emissions in 2024 and marginally lower than emissions in 2023 for the same period.
Fossil gas accounted for the largest share at 56.6% of the total, with emissions of 3.36 million metric tons for the five-month period. Compared to the first five months of 2025, fossil gas emissions fell by 1.6%, yet they were the second highest on record after 2025.
Lignite-fired power plants emitted 1.87 million metric tons in the first five months of 2026, accounting for 31.6% of total electricity production emissions. For the first five months of 2026, emissions from lignite-fired power plants were 1.3% lower than those in 2025 and the second lowest on record, though 2.6% higher than those in 2024. It is also noteworthy that this past May, lignite-fired power plants emitted 0.25 million metric tons, more than double the emissions from May of last year and more than triple those from May 2024.
Finally, oil-fired power plants on the non-interconnected islands emitted 0.53 million metric tons in the first five months of 2026, 46.1% less than in the same period last year and the lowest emissions on record due to the interconnection with Crete. Oil’s share of total electricity generation emissions in the first four months of 2026 was 8.9%.
Emissions per thermal power plant
In terms of the breakdown of emissions by power plant, the lignite power plant of Agios Dimitrios remained the top polluter for the first five months of 2026, despite reduced operation in May due to the plant’s permanent decommissioning on May 15. Specifically, the Agios Dimitrios power plant emitted a total of 1.58 million tons and was responsible for 26.6% of the sector’s total emissions.
In second place was the Agios Nikolaos II fossil gas power plant with 0.56 million metric tons, while Megalopolis V once again ranked third with emissions of 0.5 million metric tons. Rounding out the top five polluters for the first five months of 2026 were Thermoilektriki Komotinis (0.41 million metric tons) and the Ptolemaida 5 lignite-fired power plant (0.3 million metric tons), which displaced the Aluminion plant from the top five.
On the non-interconnected Islands, which no longer include Crete, the five largest polluters for the first five months of 2026 were the two power plants on Rhodes, as well as the plants on Thira, Lesbos, and Kos. Specifically, the Rhodes power plant emitted 0.098 million metric tons, the South Rhodes power plant 0.07 million metric tons, the Thira power plant 0.071 million metric tons, the Lesbos power plant 0.062 million metric tons, and the Kos power plant 0.056 million metric tons.
Sectoral emissions – comparison with NECP
In the final revised National Energy and Climate Plan (NECP) submitted to the European Commission in December 2024, emissions from the sector for 2025 should not have exceeded 10.2 million tons, while for 2030 they should not exceed 4 million tons. Assuming a linear reduction in emissions between 2025 and 2030, it follows that the carbon budget for the power sector for 2026 should not exceed 9 million tons.
So far in 2026, the electricity production sector is estimated to have emitted 5.93 million tons, or 66.2% of the annual carbon budget. This means that for the remaining of the year, 3.03 million tons of emissions remain for the country to meet its NECP commitments.
You can explore how electricity sector emissions evolved since 2013, as well as find analyses from previous months here.
