Greece’s first battery storage system under way in the Aegean Sea

The island of Tilos in Greece’s Aegean Sea is going to host the country’s first renewable energy plus battery storage system. The microgrid will be able to support the island’s population, replacing diesel generators. Ilias Tsagas of pv magazine explores why this is so significant for Greece.

hills of greek island Tilos

Greek geography: perfect for renewables and storage (Public Domain)

Tilos is a Greek island located in the south-eastern Aegean Sea, with a population of about 500. The island has often generated big news, and about a decade ago its mayor carried out Greece’s first same-sex weddings between two men and two women respectively, despite Greece then not allowing same-sex partnerships.

This time, Tilos is preparing to embrace another first, although on a totally different front. The island is soon to host Greece’s first ever battery storage system and smart microgrid based on renewable energy.

Tilos’ project comprises 13 enterprises and institutes from 7 European states and its “main goal is to demonstrate the potential of local and small-scale battery storage to serve a multipurpose role within an island microgrid that also interacts with a main electricity network. Among others, the project aims to achieve large-scale renewable energy systems penetration and asset value maximization,” says the project coordinator.

The battery project in Tilos will be part of a microgrid system that also comprises wind and solar PV facilities, along with demand side management (DSM) aspects and control system hardware and software. Given Tilos’ links to the electricity grids on the neighbouring islands of Kos and Kalymnos via a submarine cable, the battery project will support both stand-alone and grid-connected operation. Overall, Tilos’ battery system will allow the maximization of renewable energy absorption (e.g. solar PV), stabilize the grid, export energy to the neighbouring islands whenever possible and even provide ancillary services to the main electricity grid of Kos.

Dr Dimitris Zafirakis, of the Piraeus University of Applied Sciences, which is the coordinator of the project, told pv magazine that Tilos’ system installation will commence in June and conclude by the end of the summer. Testing will start immediately after.

System characteristics

Greek energy regulator RAE has licensed the Tilos project, which will include a photovoltaic park of 160 kW capacity, a sole 800 kW wind turbine and two battery containers of 1.44 MWh/400 kW each. According to RAE’s license, Tilos’ hybrid system will guarantee a power output of 400 kW for 5 hours per day.

Greece’s Eunice Energy Group, a renewable energy developer, will provide financing for the purchase and installation of the renewable energy facilities, while the rest of the project is fully funded from the European Union.

Piraeus University of Applied Sciences provided an initial study for the project and now coordinates it, while Berlin-headquartered Younicos, a leading intelligent battery solutions provider, is responsible for the design and implementation of the system’s real-time operations management.

The project’s DSM is covered by Germany’s leading EPC and energy management company Eurosol Energy Solutions, which has developed a prototype smart meter and DSM device, already rolled out in several island households.

Italy’s FZSonick (former Fiamm) provides the batteries, which together with advanced inverters have been used to build an integrated battery storage system, fully tested at Younicos’ laboratories in Berlin. Upon completion of the project, Eunice will be responsible for its commercial operation

Nevertheless, Zafirakis told pv magazine, the Tilos project has a well-defined business model, which builds on the legal framework for hybrid systems in Greece. In fact, Zafirakis added, Greece does not have currently a policy framework for battery storage. The project in Tilos was able to go through building on the regulatory framework for hybrid systems. Based on this, there are opportunities for the development of similar projects in the country, however we hope that the Tilos project will offer us an opportunity to improve the business model further, specifically with regards to the use of the battery technology, Zafirakis concluded.

Greek islands need solar plus storage urgently

pv magazine has explored the case of Greece’s islands before. Most of the country’s isles are not interconnected to Greece’s mainland electricity grid, and rely predominantly on power produced via diesel generators. Apart from environmentally hazardous, energy generation from diesel has also an extortionate cost, on average up to three times higher than in the mainland Greece.

Islanders do not bear this extra cost exclusively, which instead is subsidised via the electricity bills of electricity consumers all over Greece. Consecutive national and local governments have done very little to alleviate the islands from the diesel power production, which does not make environmental or financial sense.

This article has been republished from PV Magazine.

Ilias Tsagas: Greek-born Ilias has written for pv magazine since 2012, reporting on renewable energy news, electricity market developments and energy policy. His geographic area of expertise includes Europe and the MENA region.


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  1. heinbloed says

    That is good news!

    No coal/diesel power, same sex marriages ….. is there a hotel speaking Polish;) ?

  2. Tried to get the Greeks interested in a more substantive (& fully funded project – with no need for EU or public money). Total waste of time – couple of visit to Greece – got nowhere – advice to anybody wanting to do business in this area in Greece – don’t bother, don’t waste your time, don’t waste your money.

  3. Ilias says

    Hi heinbloed,

    I am not sure if there is a hotel that speaks Polish 🙂
    However, the Tilos island is very welcoming towards non-Greeks. In fact, there is a welcome shelter for Syrian refugees that arrive in the island. Obviously, Polish are different, since we are all together in the EU and happy to co-exist. But in general, I would say the island is very positive towards foreigners.



  4. Ilias says

    Hi Mike,

    whether we like it or not, this kind of innovative projects with emerging tech very often need public funding. The EU is currently funding a plethora of such projects, it is not only Greece that received EU funds. In fact, I was in a conference last week where British people from Centrica were explaining how the EU is funding an innovative community energy platform in Cornwall, UK.

    You are entitled to have your opinion on Greece’s business environment, however the Tilos project is proceeding very well.



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