Providing energy to small, remote communities like the Greek island of Tilos can be a complex task, which is often reflected in the price. We spoke to Dr Dimitrios Zafirakis about the TILOS project’s work in establishing a smart energy microgrid on the island of Tilos which, together with communityscale battery storage, will help more closely match renewable energy supply to demand
Local scale energy storage – challenging conventional supply and demand models The Greek island of Tilos is located in the southern Aegean Sea, roughly midway between its larger neighbours Kos and Rhodes. Currently, Tilos’s electricity is supplied via an undersea cable that carries oil-based generated power from Kos to Tilos, via the island of Nisyros, but now researchers in the TILOS project are investigating an alternative approach. “We’re going to establish local scale battery storage which interacts with renewable energy sources (RES) – wind and photovoltaics (PVs) – on the supply side, together with work on demand-side management (DSM) aspects on the consumer side. We’re going to install smart meters and DSM devices into local residences on Tilos and develop a centralized energy management system (EMS) that will allow communication between the supply and the demand side, with the support of an advanced battery storage system,” says Dr Dimitrios Zafirakis, the project’s Coordinator. The smart microgrid on Tilos will maintain communication with the main electricity system of Kos, in order to increase the security of supply and also offer guaranteed energy exports through the battery storage system. This energy scheme challenges conventional thinking. “Previously it was thought that you had to decide between having an interconnector and a storage asset. We are trying to prove that they can in fact be complementary,” says Dr Zafirakis, who stresses that “this is also in line with the fact that the electricity demand of Tilos presents considerable fluctuation over the course of a year and thus energy trade with the host grid of Kos could be really meaningful.” Tilos has a population of around 500, which swells to between 1,000-1,500 during the summer tourist season, leading to increased energy consumption.
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“Overall, Tilos has an annual energy consumption of around 3 GWh and an average load demand of 250 kW, which however rises to 1 MW during the peak summer period,” outlines Dr Zafirakis. Measuring instruments installed on Tilos island. Below Image: Solar Radiation Station.
Battery storage The battery storage system is based on FIAMM technology NaNiCl2 batteries, comprising two battery containers with a total energy capacity of 2.88MWh and nominal power of 800kW. This is projected to last for a total of 4,500 full cycles, potentially providing more than 15 years of guaranteed operation. “The system promises efficiencies in the order of 85 percent round-trip, allowing also for deep discharges. So they are quite an advanced battery storage technology,” continues Dr Zafirakis. With the energy balancing abilities of the battery system, the project is looking to maximize the local penetration of RES, in particular wind and PVs. “We’re going to install an 800 kW wind turbine on Tilos, plus PVs of 160 kW, trying also to minimise the environmental footprint of the installation, expecting to achieve annual RES penetration of more than 85 percent for the entire island,” says Dr Zafirakis. Furthermore, it is also planned that the battery system will provide guaranteed energy exports to the host grid of Kos, which suggests a valueadding energy stream for the storage asset and the community-scale smart microgrid.
Demand side management Additionally, researchers plan to install 150-200 smart meters at local residences, public buildings and pumping stations on Tilos, generating more data on consumption patterns. “We will be able to monitor local consumption, and at the same time control some of these energy loads based on the residents’ consent,” says Dr Zafirakis. DSM devices will handle three different electrical loads per house, supporting the operation of the smart
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