This project was submitted in the following language: English (en).

Project description

Two independent upper reservoirs: “Agios Georgios” (capacity~5x10^6 m3) and “Pyrgos” (capacity~2x10^6 m3) and a common lower reservoir, Kastraki Lake, built in 1960. Two independent Power Stations.

Upstream and downstream plain intakes and gates shaft.
Power system:
-Agios Georgios tunnel and vertical shaft 2800m–four reversible Units (turbine and pump with motor-generator)
-Pyrgos tunnel and vertical shaft 1600m-two reversible Units
Independent semi-outdoor power stations, Ultra High Voltage Substation 20/400kV, High Voltage Line 400kV 20 km.
Total Installed capacity: 680 MW (460+220) - production mode and 730 MW (496+234) – pumping mode
Annual energy production: ~ 816.00 GWh (552+264)

Country, Region

Greece [Στερεά Ελλάδα (Sterea Ellada)]

Start date

March 2017

Estimated project cost

EUR 502 million


Renewable Energy Production

Energy Efficiency

Asset ownership


Project type


Project status

Main Design completed - under permitting procedure

Revenue type


Economic rationale / Business Model

Hydro Pumped storage (HPS) investments, play a key role in energy systems. They supply more flexibility and balancing to the grid, providing back-up to intermittent renewable energy, facilitating the entrance of renewables, accelerating the de-carbonization of the electricity grid and ensuring higher security of energy supply.
The Greek grid system is not flexible and stable enough to accommodate large amount of intermittent RES penetration. The major production share is based on conventional thermal units (lignite and combined cycle gas turbines) with high technical minima and inability of adaptation to frequent demand fluctuations. In order to ensure efficient integration of RES and better adjustment of thermal plant operation, HPS plants are crucial for securing electricity supply, while acting as a back-up for intermittent renewables. They provide large-scale storage capacity and several distinct Ancillary Services to the system, such as frequency control, voltage control, spinning reserve, standing reserve, black start etc.
The HPS’s financial viability is based on a representative energy market, where there is significant difference in pumping and producing prices and ancillary services remuneration.

Financing details

Financing source: Private

The promoter has received / applied for EU / EIB financing support related to this project.

Existing or potential bottlenecks for the realisation of the project / Potential risks

The existing marginal prices of the Greek Electric system, regarding the daily load curve are not representative (small differences in the prices between peak and base load). More representative prices are needed for the produced hydroelectric energy and low prices for energy pumping.

Publication: 30/05/2016 | Last update: 06/04/2018

The Commission gives no warranty and makes no representation, whether expressed or implied, that the Project Information is error free. The Project Information is provided without any guarantees, conditions or warranties as to its accuracy.