Increasing installed capacity at HEDNO HV/MV Substations to enable the Connection of New Renewable Energy Sources

As part of Action 16899, “Increasing Installed Capacity at HEDNO HV/MV Substations to enable the connection of new Renewable Energy Sources (RES)”, funded by the Recovery and Resilience Facility (National Recovery and Resilience Plan “Greece 2.0”), HEDNO has implemented projects to increase the capacity of existing High Voltage/Medium Voltage (HV/MV) substations throughout Greece.

Project Objective

The primary objective of the investment is to address capacity constraints and network congestion within the Distribution Network, enabling the timely integration and connection of new Renewable Energy Sources (RES) projects. This upgrade represents a key step towards achieving Greece’s green transition objectives, making a significant contribution to the country’s goal of becoming a climate-neutral economy by 2050.

Key Figures & Funding

Total Project Budget: €37 million

Recovery and Resilience Facility Grant: €12 million

Total Capacity Increase: 725 MVA

Scope

The project comprises a series of interventions at 14 HV/MV substations across Greece, including:

Replacement of existing power transformers with new units of higher capacity and efficiency.

Capacity expansion of substations through the installation of additional power transformers.

Technical upgrades (e.g. the addition of MV feeder bays) to increase installed capacity and enhance the network's ability to accommodate power generated by Renewable Energy Sources.

Regional Distribution of the Capacity Increase

Attica

125 MVA

Central Greece

150 MVA

Peloponnese & Epirus

150 MVA

Macedonia & Thrace

300 MVA

Detailed Project Information by Substation

The table below summarizes the upgrade works carried out at each substation.

Substations	Description of works
Florina 150/20 kV Substation	Replacement of two 150/20 kV, 25 MVA power transformers with new 50 MVA units
Meliti Ultra High Voltage Station	Expansion through the installation of a second 150/20 kV, 50 MVA power transformer
Skydra 150/20 kV Substation	Expansion through the installation of a third 150/20 kV, 50 MVA power transformer
Spercheiada 150/20 kV Substation	Expansion through the installation of a second 150/20 kV, 50 MVA power transformer
Eordaia 150/20 kV Substation	Replacement of two 150/20 kV, 25 MVA power transformers with new 50 MVA units
Trikala Ultra High Voltage Station	Expansion through the installation of a third 150/20 kV, 50 MVA power transformer
Megara 150/20 kV Substation	Replacement of three 150/20 kV, 25 MVA power transformers with new 50 MVA units
Magiko 150/20 kV Substation	Expansion through the installation of a third 150/20 kV, 50 MVA power transformer
Domokos 150/20 kV Substation	Replacement of two 150/20 kV, 25 MVA power transformers with new 50 MVA units
Ioannina I 150/20 kV Substation	Expansion through the installation of a third 150/20 kV, 50 MVA power transformer
Arachthos Ultra High Voltage Station	Expansion through the installation of a third 150/20 kV, 50 MVA power transformer
Oinofyta 150/20 kV Substation	Replacement of two 150/20 kV, 25 MVA power transformers with new 50 MVA units
Pylos 150/20 kV Substation	Replacement of two 150/20 kV, 25 MVA power transformers with new 50 MVA units
Filippoi Ultra High Voltage Station	Installation of a new 150/20 kV, 50 MVA power transformer

This project is being implemented under the National Recovery and Resilience Plan “Greece 2.0”, with funding from the European Union – NextGenerationEU.