Securing sustainable energy independence for the Greek islands: the role of storage

Until recently, there were 32 autonomous power systems in the Greek islands of the Aegean Sea (non-interconnected islands or NIIs), all of which depended on fossil fuels (diesel and heavy fuel oil) from thermal plants as their primary source of power. While certain islands are going to be connected to the high voltage grid of mainland Greece in the near future, those islands for which no interconnection is planned are envisaged to become self-sustaining “smart islands,” eventually able to meet all their energy needs through a combination of renewables and energy storage infrastructure. Though challenges may lie in adapting successful projects from island to island, the pilot projects that will be implemented in the near future will undoubtedly serve as models for the expansion of sustainable renewable energy (RE) and storage-based systems throughout the Aegean Sea.

The project currently closest to full operation is TILOS (Technology Innovation for the Local Scale – Optimum Integration of Battery Energy Storage), an innovative hybrid RE-based battery project installed on the homonymous island of Tilos. With a population of approximately 500 residents (excluding seasonal tourist influxes), Tilos has been meeting its energy needs of about 3GWh annual consumption with fuel imported from neighbouring Kos island, via a subsea cable. The TILOS Project, the first of its kind in Europe, combines wind and solar PV technologies (i.e. an 800kW wind turbine and a 160kWp solar PV facility) with a prototype battery system based on NaNiCl2 batteries and battery inverter. Besides the electricity production and storage system (which has a 2.4MWh capacity), the project includes smart metering and demand side management devices. The project received its first licence in May 2016, while a power purchase agreement (PPA) (the first ever PPA for a hybrid power plant) was concluded between EUNICE Energy Group, the project’s sponsor, and the Hellenic Electricity Distribution Network Operator (HEDNO) in January 2018. The project’s trial operation commenced in April 2018 and is expected to cover 70-75 per cent of the electricity demand on the island, with excess power potentially being exported to Kos island via the existing subsea cable.

Northwest of Tilos, on the island of Ikaria, a hybrid RE project combining a 2.7MW wind farm and a 4.15MW pumped hydro system is due to commence its trial operation this summer. The project is run by PPC Renewables, the renewables focused subsidiary of the largest power utility in the country. This project is expected to cover 50 per cent of the electricity demand on the island.

Finally, with the support of the EU Smart Islands Initiative, the Greek Ministry of Environment and Energy, together with HEDNO and the Regulatory Authority for Energy (RAE), have embarked on the process to select three Aegean islands as part of a pilot project to become smart islands, each with a tailored combination of RE and storage technology to meet its energy needs. The islands which have been chosen are Astypalaia, Symi, and Kastellorizo, while the key criteria for the decision are understood to have been the islands’ medium size (to justify the significant costs of investment required) and their autonomy, since these islands are not scheduled for connection to mainland Greece. Interconnection is planned primarily for larger islands with significant energy consumption, such as Syros, Mykonos, and Paros, which were connected in Spring 2018. More interconnections are planned in the coming years, culminating in the connection of the largest Greek island (Crete) to Attica, by 2023. The aim of the smart islands pilot project is to increase the share of RE to 60-70 per cent of each island’s electricity consumption. The Greek Energy Regulator (RAE) is expected to launch international tenders, within 2018, for the implementation of the smart island projects.

Recent changes to the regulatory framework concerning the net-metering regime are also helping to further promote customers’ transition to energy self-sufficiency through the installation of small-scale renewable energy systems combined with energy storage facilities.

The success of such projects, which harness ample renewable resources and combine them with innovative storage technology, is likely to have wide-ranging implications , beyond securing energy independence for the islands of the Greek Archipelago, and may serve as models which can be adapted to enhance energy autonomy of similar isolated island power systems throughout the world.