One year of operation has been completed for the Special Pilot Project “Agios Efstratios – Green Island”, a landmark initiative in Greece’s energy transition — with the Hellenic Electricity Distribution Network Operator (DEDDHE) playing a decisive role.
A Renewable Energy Milestone
Between March, April, and May 2026, renewable energy sources (RES) accounted for up to 98% of the island’s monthly electricity generation. This dramatic shift significantly reduced both the runtime and operating costs of the conventional thermal power plant, while substantially lowering the island’s environmental footprint.
An Integrated, Sustainable Energy System
The project serves as a blueprint for transforming Greece’s non-interconnected islands into cleaner, more sustainable energy systems. It combines RES-based electricity generation — via a wind turbine and photovoltaic plant — with advanced energy storage solutions, including battery systems for electricity and thermal energy storage using insulated water tanks for district heating. This integrated hybrid power station meets most of the island’s energy needs using clean sources.
DEDDHE’s Critical Role
Implemented by the Centre for Renewable Energy Sources and Saving (CRES) on behalf of the Municipality of Agios Efstratios, and co-funded by the European Structural and Investment Funds (ESPA), the project relied heavily on DEDDHE’s technical leadership. As the system operator for Greece’s non-interconnected islands, DEDDHE designed and deployed cutting-edge automated control processes and innovative algorithms to manage the island’s electricity grid reliably and safely under all conditions.
The system operates fully autonomously through a custom-built dispatch program that recalculates and implements the optimal mix of generation resources every 20 minutes — adjusting dynamically to real-time demand and weather conditions. To ensure seamless integration between the thermal plant and the hybrid station, DEDDHE upgraded its SCADA-EMS (Supervisory Control and Data Acquisition – Energy Management System), developed new operational protocols and algorithms, conducted extensive testing, and maintains continuous monitoring and performance optimization.
Hybrid station commissioning tests began in July 2025, and full commercial operation commenced in November of the same year.
Scaling Up the Model
The expertise gained by DEDDHE through this pioneering project paves the way for replicating high-penetration RES and hybrid power stations across Greece’s non-interconnected islands — accelerating the national energy transition and reinforcing sustainable development in island communities.