Smart microgrids and power reliability on Greek island of Tilos

A Greek smart microgrid project is testing a local battery storage system for multiple use cases including island grid stability.
Published: Thu 01 Mar 2018

With their small size and limited populations, islands make an ideal environment for developing microgrids.

Greece’s Piraeus University of Applied Sciences and its partners have seized this advantage to contribute to the innovation of microgrids with their own project - TILOS (Technology Innovation for the Local scale Optimum integration of battery energy Storage).

TILOS was initiated on the Greek island of Tilos to demonstrate the potential of a local, small-scale battery storage system and will run until February 2019.

Supported by the European Union’s Horizon 2020 research programme, it serves a multipurpose role within an island microgrid that also interacts with a main network.

The island is now a step closer to fully integrating and utilising its microgrid. In January 2018, a power purchase agreement (PPA) was issued for a hybrid power station, which is currently at commissioning stage and should enable a trial operation to commence in the next few weeks, according to Dr Dimitris Zafirakis, Project Coordinator of TILOS.

“The hybrid power station consists of three different components: a wind turbine, a small-scale PV (photovoltaic) power station and an integrated battery storage system,” describes Dr Zafirakis. Thanks to this, Tilos can soon run mainly on renewable energy.

Battery storage and the microgrid - use cases

The island of Tilos is part of the Dodecanese island complex in the southeastern Aegean Sea.

With a population of about 500 people, the island’s electricity needs are served via an undersea interconnection to the host grid of Kos and Kalymnos islands, where a diesel oil power station is operated. However, outages are frequent and often long-lasting due to cable faults.

The main objective of the TILOS project is the development and operation of a prototype sodium nickel chloride-based battery system to support multiple use cases.

Among these are microgrid energy management, maximisation of renewables penetration, grid stability, export of guaranteed energy and ancillary services to the Kos main grid. In addition, in the event of a cable fault, a smart energy management system will be able to isolate the island and reconnect it to Kos as soon as the fault is restored.

Though the Kos diesel station is still fulfilling the island’s electricity demands, the short to medium-term goal of the hybrid power station is to meet 70% to 75% of Tilos’ energy needs. “The remaining 25% will still be coming from the power cable from Kos, although our goal is to reach 100% at a later stage,” says Dr Zafirakis.

In fact, the hybrid power station could cover the entirety of the local energy demand for the biggest part of the year, except the peak summer months, and even sell any surplus energy produced back to Kos through the interconnected power cable.

Tilos is expected to run mainly on renewables soon.

Engaging Tilos energy consumers

Tilos’ locals are an essential factor for the project’s success, says Dr Zafirakis. “We have been in constant communication with the locals, training them in the technical aspects of the smart microgrid. We have also started exploring the idea of an energy cooperative, investing in the system to reach renewable shares close to 100%.”

Another recent achievement was the successful implementation of 100 smart meters and demand side management (DSM) devices in local residences and stores. This step is essential to further integrate local residents with the project. The locals will be engaged in implementing DSM strategies, which is also expected to produce benefits in terms of energy savings.

Additionally, he says, “we have engaged them through a series of training seminars, educational seminars, questionnaires, surveys and so on. So they are really willing to provide us with the information necessary, and they have also embraced the project, especially when realising that this was a very positive thing for their island.”

Microgrids - opportunities for utilities

Another benefit of the engagement with locals and project partners is the opportunities presented to utilities. For instance, according to Dr Zafirakis, the Greek distribution system operator HEDNO “is involved in the project as a partner, harvesting and exchanging know-how on the smart elements of the microgrid, especially with regards to the development of the DSM side.”

In his view, achieving 100% renewables integration would “require that the local energy cooperative is first developed.” The implementation of this initiative is currently being studied alongside the Tilos Municipality.

Utilities can then play a part in similar microgrid projects by focusing on cooperative aspects, “with emphasis given on the deeper understanding of technical challenges and also business models deriving from the actual operation of similar smart microgrids, alongside the active participation of local people, such as through the creation of an energy cooperative.”

Renewable energy for Mediterranean islands

The TILOS project is blazing the trail for other similar projects in Greece and in other islands. “By signing the first-ever PPA for a hybrid power station in Greece, this can commercialise our solution, which also makes it replicable. This was the first-ever battery-based hybrid power station that was licensed by the Greek authorities, and this enables the replicability in other islands.”

Dr Zafirakis mentions the positive example of the Greek island of Ikaria, which is also in the process of acquiring a hybrid power station of its own but has not yet been granted a PPA for it.

The project is also of relevance to other islands internationally. In particular, it will engage the islands of Pellworm off the coast of Germany, Portugal’s La Graciosa in the Azores, and Corsica in order to share implementable results and the transfer of technological experience.

Thus the most important lesson to be learned from the TILOS project, according to Dr Zafirakis, is that it is expected to offer a potential to other European and Greek islands that are dependent on oil-based energy imports.

“We are establishing a new energy paradigm for island regions, looking at the development of a scalable, versatile, community-level energy solution that can be replicated in numerous islands across the globe, making them more energy resilient,” says Zafirakis.