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Based on the latest available electricity generation data (September 2026 for the interconnected system and August 2026 for the non-interconnected islands) and the 2025 annual CO2 emissions data under the EU ETS, monthly emissions are estimated for each electricity generation unit in Greece covered by the EU ETS, following the methodology and assumptions presented here.
Total emissions
Following the end of the summer, the upward trend in emissions observed over the previous four months came to a halt. More specifically, CO2 emissions from fossil fuel-fired power generation units decreased by 22.7% compared to August, reaching 1.06 million tonnes. This significant decline was mainly driven by fossil gas and, to a lesser extent, oil, while emissions from the last remaining lignite-fired power plant, Ptolemaida 5, remained almost unchanged. Compared to September 2025, total CO2 emissions also decreased by 8.3%, reflecting lower emissions from all three fossil fuels.
Cumulatively, emissions from power generation units reached 10.66 million tonnes over the first nine months of 2026, marking a historical low for this period of the year. Compared to the same period in 2025, emissions were down by 10.3%, a performance largely attributable to the drastic reduction in the operation of Crete’s oil-fired power plants, following the completion of the island’s interconnection with the mainland electricity grid.
Carbon intensity
The decline in the sector’s total monthly emissions also led to a reduction in monthly carbon intensity, which stood at 204.3 g CO2/kWh, down 0.6% compared to August. The decrease in carbon intensity was marginal, as the reduction in emissions was accompanied by a decline in monthly electricity generation. However, compared to September 2025, carbon intensity fell much more significantly, by 12.3%, as a combined result of lower emissions and increased electricity generation.
Over the first nine months of 2026, average carbon intensity stood at 213.1 g CO2/kWh, down 20.6% compared to the 2025 average, reaching a new historical low.
This performance would have been even better had RES curtailments been lower, estimated at 2,063 GWh for the first nine months of the year (7.8% of total RES generation), according to IPTO’s ISP2 and ISP3 forecasts. Had the curtailed energy been stored and subsequently used to displace electricity generation from fossil gas and lignite, average carbon intensity would have stood at 193.1 g CO2/kWh, i.e. 9.3% below the actual level.
Emissions per fuel
Over the first nine months of 2026, fossil gas retained the largest share of the sector’s emissions, accounting for 6.4 million tonnes and a 59.9% share of the total. Compared to the same period in 2025, when emissions reached a historical high, emissions from gas-fired power plants declined only marginally (-3.4%), while remaining 7.7% higher than in the corresponding period of 2024.
Lignite-fired power plants emitted 2.67 million tonnes over the first nine months of the year, maintaining a significant share of total emissions at 25%.
Finally, oil-fired power plants on the non-interconnected islands emitted a cumulative 1.3 million tonnes, accounting for 12.2% of total emissions and recording their lowest emissions for this period of the year, down 44.3% compared to the same period in 2025.
Emissions per plant
The Agios Dimitrios lignite-fired power plant remained in first place among the top emitters over the first nine months of 2026, despite its permanent closure on 15 May. Its cumulative emissions amounted to 1.58 million tonnes, accounting for 14.8% of the sector’s total emissions over the first nine months of the year.
Driven by its increased generation in recent months, the lignite-fired “Ptolemaida 5” plant moved up to second place, with 1.09 million tonnes, pushing the fossil gas-fired Thermoelectric Plant of Komotini into third place, with 0.96 million tonnes. Fourth place went to the fossil gas-fired Agios Nikolaos II power plant, with 0.9 million tonnes, which did not operate at all in September. The top five emitters over the first nine months of 2026 were rounded out by another gas-fired power plant, namely Megalopoli V, with 0.87 million tonnes.
In the non-interconnected islands, following Crete’s interconnection, the five largest emitters over the first nine months of 2026 were the two power plants on Rhodes, followed by the plants on Thira, Kos and Lesvos. Specifically, the Rhodes power plant emitted 0.271 million tonnes, the South Rhodes power plant 0.192 million tonnes, the Thira power plant 0.188 million tonnes, the Kos power plant 0.163 million tonnes and the Lesvos power plant 0.117 million tonnes.
Comparison with the NECP
Despite the progress made in reducing emissions from the power generation sector over the first nine months of 2026 (mainly driven by lower oil-related emissions), continued heavy reliance on fossil gas appears to be putting the country off track from meeting its commitments under the National Energy and Climate Plan (NECP).
More specifically, according to the final updated NECP, emissions from the sector should not have exceeded 10.2 million tonnes in 2025, while they must remain below 4 million tonnes by 2030. Assuming a linear decline in emissions between 2025 and 2030, the power generation sector’s carbon budget for 2026 consistent with the NECP amounts to 8.96 million tonnes.
Based on the data for the first nine months of 2026, emissions from the power generation sector are estimated to have reached 10.66 million tonnes, thus exceeding the projected carbon budget for the entire year by 1.7 million tonnes, or 19%.
You can explore the evolution of emissions from the power generation sector from 2013 to date and read previous monthly analyses here.
