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Making island energy grids more efficient and sustainable

Energy costs more on islands, as they are typically isolated from the national grid. While greater use of renewable energy could lower these costs, most European islands don’t have the necessary grid infrastructure. The EU-funded INSULAE project’s demonstrations showcased the technical and economic viability of decentralising island energy supplies, paving a way to affordable, sustainable energy.

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For the 15 million Europeans living on an island, energy can be extremely expensive – bills are three to four times higher than on the mainland.

“Isolation from mainland grids gives rise to smaller, more isolated grid systems,” explains Leon Nielsen, project manager at CIRCE Technology Centre in Spain. “Even where interconnection does exist, it may be in the form of a single cable, which leaves the entire grid very vulnerable to outages.”

What’s more, many islands rely on expensive imported fossil fuels to generate their electricity, meaning that island grids tend to have an outsized carbon footprint.

“The irony here is that islands have readily available renewable resources,” says Nielsen. “From tidal to wind, solar, hydro, geothermal and biomass – islands have renewable options, and by exploring each island’s characteristics, one will find that there is always a path to greater renewable energy use, energy independence and carbon zero.”

The challenge is that the small, isolated grids found on most islands aren’t equipped to handle high percentages of renewables. Helping Europe’s islands overcome these challenges and better leverage their renewable energy potential is the EU-funded INSULAE project.

“By helping islands scale up renewables, energy efficiency, storage and clean transport, the INSULAE project aimed to provide a more stable supply of cheaper, cleaner and more dependable energy,” adds Nielsen.

Demonstrating the potential of renewable energy

To accomplish this goal, the project conducted a number of pilot demonstrations on the islands of Unije in Croatia, Bornholm in Denmark and Madeira in Portugal.

On Unije, the project looked at the use of solar panels and batteries as a means of achieving 100 % decarbonisation. Researchers also worked to address the island’s water scarcity by integrating the water system into the electrical system.

“We were able to demonstrate how small, water-scarce islands can use curtailed renewable energy to desalinate brackish groundwater or ocean water, to alleviate the need for carbon-intensive water tankers – thus providing ‘carbon-free’ water to citizens,” notes Nielsen.

On Bornholm, the project focused on installing a novel superfast electric vehicle charging system and battery, based on a fully direct-current architecture, using solar energy.

Researchers also investigated how an existing biogas installation might be upgraded to produce higher value fuel using electrolysis. “The idea here was to position biogas as a reliable source of energy to fill in the gaps not met by other renewable sources and to see the capacity of an existing local grid to respond to the challenges of very high renewable penetration,” remarks Nielsen.

In Madeira, INSULAE studied the use of novel smart charging and vehicle-to-grid (V2G) technology to smooth energy demand. “We demonstrated how V2G technology, which pushes energy from an electric vehicle’s battery back into the power grid, could help island grids navigate the peaks and valleys of energy use, especially considering the foreseen increase in electricity demand due to the electrification of transport,” says Nielsen.

In addition to the demonstrators, the INSULAE project also developed an innovative investment planning tool. Designed specifically for the island context, the software programme can be used to help with higher-level energy planning.

“In short, the tool allows one to model the state of an island’s current energy system and then plan future energy scenarios evolving over time,” explains Nielsen. “This includes, for example, expected changes in demand and the integration of renewables for optimising carbon reduction or other specific aims of the island community using it.”

Decentralising the energy supply

According to Nielsen, many of the demonstration technologies developed during the project are in the final stages of commercialisation. In some cases, they have already been adopted by other islands and locations not involved in the project.

“The research and technological developments from INSULAE clearly demonstrate the technical and economic viability for decarbonising and decentralising the energy supply of islands,” concludes Nielsen. “I am confident that our work will ultimately provide islands with greater autonomy in terms of energy supply and security while also reducing energy costs and, most importantly, decreasing carbon emissions.”

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Project details

Project acronym
Project number
Project coordinator: Spain
Project participants:
United Kingdom
Total cost
€ 11 735 177
EU Contribution
€ 9 630 773
Project duration

See also

More information about project INSULAE

All success stories