Greece Installed 1.89 GW Of Solar Capacity in 2025 Amid Crippling Grid Delays

Greece's total installed solar power capacity was increased by 1,893 megawatts (MW) in 2025. The new total installed capacity is now 11.5 gigawatts (GW) according to the Hellenic Association of Photovoltaics (HELAPCO).

While 2025's additional 1.893 MW of installed solar capacity represents a significant decline from the record-setting 2.57 GW of capacity installed in 2024, solar power continues to be the driving force of Greece's energy transformation. Additionally, another 800 MW of projects already constructed and waiting connection to the grid will come online in 2026.

In spite of these milestones, however, there are signs that Greece continues to experience a major challenge as a result of increasing use of solar energy. The Greek electric grid was created years prior to any significant use of solar energy, and is under great strain as the use of solar energy continues to grow. Over the last several years the Greek state has granted more than 110 GW of renewable energy licenses-72.4 GW of which are for photovoltaic-while grid capability for renewable energy in Greece is only 19 GW. As a result, there is approximately 9:1 difference between all of the renewable energy projects that have been licensed by the state and the amount of grid capacity that exists, which raises fundamental concerns about the future development of renewable energy in Greece.

In the first half of 2025, grid operators curtailed approximately 1,327 GWh of renewable electricity-equivalent to 9.6% of total renewable energy output, with single-month curtailments spiking as high as 12% in June. By year's end, total curtailed energy is estimated to have exceeded 2 TWh, and experts warn that 2026 could see curtailments reach between 3.3 TWh and 3.7 TWh, representing a roughly 75% increase.

"The trick is to balance supply and demand. If you don't do it well, you get a blackout," Nikos Mantzaris, a senior policy analyst at the independent civil organization Green Tank, told AFP earlier this year. Greece's national grid operator repeatedly ordered thousands of medium-sized operators to shut down during peak sunlight hours to avoid overloading the network and triggering a blackout.

SPEF chairman Stelios Loumakis described the situation as saturated. The Greek state, he said, approved too many photovoltaic projects over the past five years, leading to a "severe production surplus" on sunny days.

The grid bottleneck is no longer merely a technical challenge-it has become a financial one. Greek banks, which have embraced green lending as a pathway to sustainable growth, now face growing exposure to an overheated market. As curtailments rise and grid delays mount, the risk of underperforming or delayed projects grows. If projects fail to generate expected income, borrowers may struggle to service debt.

Renewable energy aggregators have warned that rising curtailments have already caused roughly 20% revenue losses for PV producers in 2025, while the number of hours with zero or negative prices in the day-ahead electricity market nearly doubled.

Despite facing major challenges, the development of solar power continues to be successful. The PPC group of companies has constructed a massive photovoltaic array (PV) of 2,130 MW on former lignite mines in Western Macedonia, now known as Europe's largest renewable energy generation facility. This array includes the 940 MW Amyndeo complex, and the 550 MW Phoebe facility, which are meant to generate 3,150 GWh per year of usable electricity and provide approximately 750,000 homes with electricity – representing approximately 6% of Greece's electrical consumption each year.

In parallel, PPC Renewables has completed two electrochemical energy storage units in Ptolemaida and Meliti, with a 50 MW/200 MWh BESS in Amyndeon under construction and two pumped storage projects in Kardia and South Field moving through regulatory approvals.

Corporate power purchase agreements are also reshaping the market. German utility RWE and PPC, through their joint venture Meton Energy, are constructing two new solar parks totaling 567 MWp in Central Macedonia, backed by €418 million in investment including €175 million from the NextGenerationEU mechanism. Swiss renewable power developer Axpo has also signed a PPA with EDF Renewables Hellas for 102 MW of solar capacity from the Skala Korinis and Loutsa projects.

Additionally, Motor Oil Group subsidiary MORE and PPC Renewables are building eight photovoltaic parks with a total capacity of 882.4 MW, with electricity to be sold through bilateral PPAs to support Greek industry and agricultural producers.

The solar boom has exposed a critical vulnerability: Greece has virtually no utility-scale battery storage in operation. Stella Zacharia, CEO of Optimus Energy, noted that the country will need between 4 GW and 5 GW of storage to fully integrate its renewable energy capacity. "Yet today, we do not even have 1 MW in operation," she said.

HELAPCO policy advisor Stelios Psomas told AFP that the next three years will be crucial for storage deployment. "Managing high shares of renewables-especially solar-requires significant flexibility and storage solutions," said Francesca Andreolli, a senior researcher at ECCO, a climate change think tank in Italy.

To address this gap, Greece has run three battery storage tenders awarding 900 MW of capacity with subsidy support. While none are yet operational, a 4.7 GW program for utility-scale, merchant-style standalone storage projects is also moving forward, alongside battery installation at existing or planned PV parks.

HELAPCO forecasts that Greece's solar installed capacity target of 13.5 GW for 2030 will be met as early as 2026. Under a reasonable growth projection, the total amount of solar capacity in Greece could be approximately 21.5 GW by the end of the decade. However, the degree to which the new solar capacity will be able to support stable and profitable electricity production will depend on the improvements made to the transmission infrastructure, as well as the roll-out of battery storage.

The goal of the Greek government is to reach 81% of renewable energy by 2030 under a revised National Energy and Climate Plan compared to 66% under the most recent plan from 2019; therefore, it will require both continuing the installation of solar energy, installing upgraded transmission systems, and quickly deploying battery storage in order to reach the needed level of renewable energy for Greece.

As Stelios Psomas of HELAPCO warned, curtailments and negative price events are already eating into project profitability. "The sector also needs support for residential and commercial storage," he said, cautioning that without rapid deployment of storage systems, Greece's solar success story risks being overshadowed by its own contradictions.

For now, Greece remains a cautionary tale of what happens when renewable generation outruns grid capacity-and a testing ground for the storage solutions that will be essential across Europe's energy future.