Greece’s energy transition: from lignite to solar, and what comes next

Half a century of lignite

The Public Power Corporation (PPC, in Greek DEI) was founded under Law 1468/1950 to build and operate hydroelectric and thermal power stations1. The aim was a national generating system, and the fuel to hand lay under the ground of Western Macedonia and Megalopoli: lignite.

For decades lignite was domestic, cheap to mine and available around the clock. Towns, mines and a whole regional economy grew up around it. In 1990 it supplied 71.9 %2 of the country’s gross electricity generation2.

The price was emissions. Lignite is a wet, low-calorific coal, so a lot of material is burned for each kilowatt-hour. That means a lot of carbon dioxide and, locally, particulates and ash, which the surrounding areas lived with for years.

Islands, oil and subsea cables

Islands that were not connected to the mainland system generated their own power in local oil-fired stations. Each was a small, separate grid that had to balance itself.

The answer has been subsea cables. Crete’s first interconnection ran to the Peloponnese, and on 3 July 2021 the mainland system began supplying the island3. The Crete–Attica interconnection entered trial operation on 24 May 20254.

Gas and the first renewables

During the 1990s natural gas went from an almost zero share to a significant source, and from the 2000s wind power grew as well2. Even so, in 2010 lignite and coal still supplied 53.6 %2 of gross generation2: less than before, but still the base of the system.

Gas had two advantages lignite lacked. It emits less carbon dioxide per kilowatt-hour, and modern gas units ramp output up and down quickly. The second would become its most valuable feature.

The 2019 pledge

On 23 September 2019, at the UN Climate Action Summit, the Prime Minister announced that Greece aimed to close all of its lignite-fired power units by 2028, even though it is a major lignite producer5.

By then lignite had already fallen to 24.9 %2 of generation2. Under the EU Emissions Trading System every tonne of carbon dioxide has to be paid for, and the fuel with the highest emissions per kilowatt-hour is the first to lose its economics.

The revised NECP of 2024 kept the date. It states that all lignite units will be withdrawn by 2028 in an orderly way, with Ptolemaida 5 as the last unit6.

Where the mix stands today

In 2024 lignite supplied just 5.6 %2 of gross generation and solar 19.4 %22. For 2025, monthly net generation data give natural gas 44.5 %7, wind 20.2 %7 and solar photovoltaics 17.1 %7.

Solar grew fastest. In May 2026 installed photovoltaic capacity on the interconnected system and distribution network exceeded 11.6 GW88, before counting the islands that are not yet connected. That is good news for emissions and for the bill for imported fuel. It also brings a problem that did not exist when power came from lignite: all that solar produces at the same hours, and those are not the hours when the system needs the most power.

The NECP target for 2030 is for renewables to cover 75.7 %6 of gross electricity consumption6. Lignite and coal supplied 71.9 %2 of Greece’s gross electricity generation in 1990 and 5.6 %2 in 2024, when solar alone supplied 19.4 %22.

Too much at noon, too little after sunset

Generation must match consumption at every moment. When, on a sunny spring midday, solar produces more than the country consumes and exports, the system operator asks renewable stations to reduce output. This is curtailment: energy that could have been produced at almost zero variable cost is thrown away.

The Independent Power Transmission Operator (IPTO, known in Greek as ADMIE) publishes monthly curtailment reports. We have not found an official annual total in a form that can be cited here, and we do not adopt the figures that circulate in the press. When an official total is available, it will be added with its source.

Peak demand in 2025 was 10,370 MW9, early in the afternoon of 25 July9, when solar was still helping. The more demanding hour comes a little later: the sun sets, consumption stays high, and within a short time other sources must replace what solar was providing.

Today that job falls mainly to gas units and hydropower, which ramp quickly, and to interconnections with neighbouring countries. In 2025 Greece imported 3.4 TWh10 and exported 6.4 TWh10, which made it a net exporter. The flows change direction within the day, though, and in the evening imports help. The wider regional picture is covered in nuclear power in Greece’s neighbourhood.

Storage, and what it leaves uncovered

The obvious fix is to store midday power and release it in the evening. Greece’s first battery tender selected projects totalling 411.79 MW1111, and the three tenders together selected 900.47 MW12 across 32 stations12.

The revised NECP projects for 2030 4.3 GW6 of battery storage and 1.9 GW6 of pumped storage, in which water is pumped to an upper reservoir when power is in surplus and released through turbines when it is short6.

Batteries solve the problem of a few hours. They do not solve windless, overcast winter days, which need either far more storage or a source that produces whenever required. In a solar-heavy system the most valuable megawatt-hours are the ones the sun cannot supply: at night, in winter, in calm weather. Today they come mainly from imported natural gas.

This is where the nuclear debate enters, as one option for those hours alongside storage and interconnections. Nuclear offers steady output with no direct emissions in operation, but it has its own limits: it changes output more slowly than gas, it is expensive to build and it takes many years to bring into service. No decision to build a plant has been taken; where Greece stands sets out the current position. The Greek section of this site also has an interactive grid game (in Greek) that shows the problem in 72 seconds.

The editor works as an engineer in the nuclear sector. Views here are his own and do not represent any employer. The platform receives no funding from anyone. Not yet independently reviewed by a second engineer. Read in Greek.