Project of Common Interest (PCI) – PCI 3.24


As of October 2013 the European Commission has adopted a list of 248 key energy infrastructure projects under the new guidelines for trans-European energy infrastructure. These projects contribute to market integration, enhance security of supply and reduce CO2 emissions. Carrying the label “Projects of Common Interest” (PCI) they benefit from faster and more efficient permit granting procedures and improved regulatory treatment. The list of PCIs is updated every two years.

The project “Hydro-pumped storage in Greece – Amfilochia”promoted by TERNA ENERGY S.A. has been selected as Project of Common Interest under the code name PCI 3.24.This project supports the implementation of the North- South electricity interconnections in Central Eastern and South Eastern Europe (NSI East Electricitypriority corridor of EU Regulation).

Moreover, the Project has been classified as a Strategic Investment by the Greek Authorities and has been incorporated in the related procedures under the Law 3894/2010.

The purpose of the Project is energy storing to assist renewable sources integration. The excess wind, photovoltaic or thermal energy will be hydraulically stored, through water pumping from the lower to the upper reservoirs, during the low load consumption or in renewable overproduction periods. Subsequently, energy will be recovered via turbine mode, during the peak load hours.

Project Promoter

TERNA ENERGY is a member of GEK TERNA Group of Companies and was incorporated in 1997 as a subsidiary of TERNA S.A. It is a vertically organized Renewable Energy Sources company undertaking the Development, Construction, Financing, and Operation of renewable energy projects (wind, hydro, solar, biomass, waste management). It has a strong pipeline of around 8,000 MW of RES projects in operation, under construction or in an advanced stage of development, has a leading position in Greece, with footprint in Central and South East Europe, as well as the USA.TERNA ENERGY is also active in international initiatives to further promote the use of RES. It is also a member of the European Renewable Energy Federation (EREF), among others.


Pumped storage systems

Pumped storage systems represent a giant rechargeable battery. The method stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation.They are the most mature technology to store energyat any time, usually regardless of the weather. They are smaller than conventional reservoirs and less controversial, providing they use at least one existing reservoir. Pumped storage units can start up in a few minutes, in an emergency situation, to provide the necessary reserve capacity.

Initially, the philosophy of these systems was to serve and facilitate the operation of coal-fired stations at constant levels of output, functioning more efficiently and reducing CO2 emissions. In a system with a substantial proportion of thermal plants, at base and medium load, this is more than compensated by the increase in efficiency of oil, gas and coal generators as well as the subsequent reduction in the amount of greenhouse gas emissions.

In recent years, pumped storages have played a key role in enabling energy systems develop low-carbon electricity production. They supply moreflexibility and balancing to the grid, providing a back-up to intermittent renewable energy, facilitating the entrance of renewables, accelerating the de-carbonization of the electricity grid, improving the security and efficiency of electricity transmission and distribution(reducing unplanned loop flows, grid congestion, voltage and frequency variations), stabilizing market pricesfor electricity, while also ensuring a higher security of energy supply.

Hydropower storage is the only large-scale and cost- efficient storage technologyavailable today. Despite promising developments in other energy storage technologies, hydropower is still the only technology offering economically viable large-scale storage. It is also a relatively efficient energy storage option. With approximately 80% efficiency pumped storage plants have the highest global cycle efficiency compared to other power plants.

Project description

The PCI 3.24 “Hydro-pumped storage in Greece – Amfilochia” is located in the Municipality of Amfilochia, Prefecture of Aitoloakarnania, Central Greece. It consists of two separate upper reservoirs, “Agios Georgios” and “Pyrgos”, and a common lower reservoir, the existing Kastraki Lake (Public Power Company-PPC ownership).

The electromechanical equipment will be installed in two independent powerhouses located near the north-eastern bank of the Kastraki Lake. The total installed capacity of the system is approx. 680 MW (generation) / 730 MW (pumping) and the net annual electricity generation is 816 GWh. The total budget of the project is expected to exceed the amount of 500M euros.

The Agios Georgios reservoir has an effective storage capacity around 5 x 106 m3; installed power (turbine mode): 460MW (4 reversible units); Installed power (pumping mode): 496MW. The Pyrgos reservoir has an effective storage capacity around 2 x 106 m3; Installed power (turbine mode): 220MW (2 reversible units); Installed power (pumping mode): 234 MW.

Project benefits

To the system

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) with high technical minima and inability of adaptation to frequent capacity fluctuations. In order to ensure efficient integration of RES and better adjustment of thermal plant operation, pumped storage power plants are crucial for a secure supply of electricity and as a back-up for intermittent renewables, as they can provide large-scale storage capacity and several distinct Ancillary Services to the system. Beyond electricity, the Pumped Storage Complex delivers other services to the system, such as frequency control, voltage control, spinning reserve, standing reserve, black start, remote automatic generation control, grid loss compensation and emergency control action. Pumped storage is the most mature and reliable technology, suitable for large energy storage rates, from both technical and economical points of view.

To the national energy market

The project’s impact on the internal energy market and the national economy is particularly positive, due to the reduction of the import deficit(mainly natural gas), and the greenhouse gas emissions (as a result of the lignite combustion). The hydroelectric production in an interconnected transmission grid contributes to the reduction of wind power variability and uncertainty, provides firm capacity and entails significant economic benefits in the electricity market. The above mentioned contributions to the power system are vital for the completion of the Internal Energy Market. The existence of a competitive market is intended to give European consumers a better solution instead of imported fuels and to make the market accessible for all producers, especially those investing in renewable energy.

To the European energy market

The project has a significant cross-border impact to the neighbouring countries, due to the energy transfer between Member States. The total interconnection capacity with neighbouring countries is 2000 MW, 1300 MW of which is between Greece and other Member States (Italy and Bulgaria) and 700 MW with third countries (Albania, FYROM and Turkey). The contribution of the project to energy transfer abroad is particularly considerable. According to the “National Renewable Energy Action Plan in the scope of directive 2009/28/EC” of the Greek Ministry of Environment, Energy and Climate Change, the expected transfer of Renewable Energy Sources from Greece to other EU Member States will be equivalent to 856 ktoe in 2015 and 529 ktoe in 2020. PCI 3.24 is expected to produce 816 GWh/ year, approx. 70 ktoe/year, therefore it will assist the energy transfer abroad in a significant way.

To the environment

As stated, the project’s contribution to sustainability is particularly important, as it assists the EU target of 20% greenhouse gas emissions reduction until 2020. Additionally, the reservoir is estimated to contribute both towards increasing biodiversity, as well as the populations of specific groups or species that benefit from deeper waters with lower flow rate and soft substrate. This is expected to happen due to the increase, over time, of sediment at the bottom of the reservoir. In terms of species or groups with wider living space, such as mammals, reptiles, birds, etc., the reservoir is expected to function in a positive way by increasing the total biomass of the food chain.

To the local community

The project’s implementation could contribute significantly to social and economic development of the local community. The Project’s Owner will try to develop initiatives modeled on local needs and potential. Furthermore, by choosing, whenever possible, regional and local contractors and suppliers and hiring local personnel, during both the construction and operation phase, the project could benefit directly and indirectly the economy of the areas in which it operates. Finally, the formulation of the lake and the improvement of access roads could create additional leisure facilities in the area and attract visitors and tourists.

Project status

The project has obtained production license by the Regulatory Authority of Energy (RAE) and the temporary interconnection terms offer, from the Independent Power Transmission Operator (IPTO).

At the time being, the PCI is under design development and environmental permitting.