FLASC: hydraulic solution for offshore energy storage

With seawater and compressed air, FLASC offers a solution to one of the biggest challenges of wind and solar energy: balancing energy supply and demand. The simplicity combined with the impact of the idea earned FLASC a nomination for the Offshore Wind Innovators Awards 2022.

The team from FLASC. From left to right Daniel Buhagiar, Daniel Baldacchino and Adrian Singuran

FLASC works simply: with the surplus electricity from wind turbines or solar cells, a hydraulic system compresses air by pumping seawater into a pressure chamber. The energy is released when the air expands, and the seawater produces electricity on its way out. “No scarce or risky chemicals, but techniques and materials that have long proven themselves at sea. But then in an innovative application, which also produces a high energy density in shallow water, where the water pressure is low. Such as the Dutch parts of the North Sea, where there are many wind farms,” says Daniël Buhagiar, one of the founders of FLASC. “This technique works particularly well under water because the sea ensures natural cooling of the compressed air. As a result, we avoid the energy loss that occurs on land because increasing pressure is accompanied by heating.”

In the foot of a wind turbine at sea, on the bottom under a floating wind farm; FLASC stores the energy right where it is produced.

Island of Malta as cradle

The idea arose in 2014 in Malta, Buhagiar's homeland. Buhagiar: “On a small island like Malta, land is scarce, but sea is plentiful. Looking at maritime solutions for contemporary issues is therefore obvious. I obtained my PhD from the University of Malta on offshore wind energy transmission. My research started from an academic question: how do you get the periodic energy from wind turbines evenly into the electricity grid? The advantage of such a scientific start is that you can first build up knowledge in peace and can simulate and test. This leads to robust technology that was already extensively tested before we looked at commercialization. That is important: the maritime sector does not like risks. Testing a modest prototype in practice, in the port of Malta, was the game changer. That's how we knew it worked. Since then, developers of wind farms in particular have shown interest. We see them as our primary market."


“There is an innovative climate for wind energy in the Netherlands. There was already a link with the Netherlands: Tonio Sant, my PhD professor and now also FLASC CTO and co-founder, had obtained his PhD in Delft. This Dutch connection is one of the reasons why we founded FLASC in Delft at the end of 2019. We are now working on the technology with a team of ten people, partly at the University of Malta, partly at FLASC in the Netherlands. Thanks to our strategic position in the Netherlands and being part of the Buccaneer Accelerator, our commercial network has expanded considerably."

FLASC is currently expanding its experience with more pilots, including one for the UK market with partner Subsea7. At the same time, important equipment will be commissioned this year at the University of Malta for deployment in Greece as part of a major European project. The FLASC energy storage technology is built into the platform of a floating wind turbine.

Find investors

The next step is certification of the system, expanding the team and building on a larger scale. “We need money and a commercial partner for that. Finding a platform for this is the most important task in the coming year. Nominations such as those for the Offshore Wind Innovations Awards help with that. This way we can show our potential broadly, specifically aimed at innovation projects in Dutch offshore wind farms, such as the upcoming tender for IJmuiden Ver,” says Buhagiar. "The ultimate goal is to realize our vision of accelerating the energy transition by developing and bringing to market technology that allows us to maximize the efficiency of large-scale clean energy sources."

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