A smart ofshore energy storage soluton

The frst prototype was installed in 2017 in the Grand Harbour of Malta.

A smart offshore energy storage solution

THE GROWING NUMBER OF OFFSHORE WINDFARMS WILL RESULT IN A LARGE SUPPLY OF ELECTRICITY THAT WILL AT TIMES DELIVER SURPLUS POWER AND AT OTHER TIMES NOT COPE WITH DEMAND. IN TIMES THAT MORE ELECTRICITY IS PRODUCED THAN NEEDED, IT CAN BE STORED INSTEAD OF CURTAILED. A SUITABLE BUFFER CAN STORE EXCESS ENERGY PRODUCTION AND DELIVER IT LATER TO COMPENSATE FOR DEFICITS TO MEET DEMAND. START-UP COMPANY FLASC HAS INVENTED A SMART, NONBATTERY-BASED ENERGY STORAGE SOLUTION FOR THE OFFSHORE SECTOR AND IS NOW READY FOR THE NEXT STEP.

ALL PHOTOS AND IMAGES COURTESY OF FLASC. One of the co-founders of FLASC is Daniel Buhagiar, a young mechanical engineer from Malta. “Being an island,” he says, “Malta has always depended on the sea in many ways and during my studies at the University of Malta I became interested in the sea’s potental for renewable energy. During my Ph.D. in ofshore wind energy, under the supervision of Professor Tonio Sant, we were investgatng supply and demand and looking at ways of integratng the storage of ofshore generated electricity. This was back in 2015 and resulted in a concept for an energy storage device, FLASC HPES (hydro-pneumatc energy storage) that can be installed ofshore, and even integrated directly into an ofshore windfarm. >>

From left to right the FLASC co-founders Robert Farrugia, Tonio Sant and Daniel Buhagiar.

The FLASC technology can be used to convert intermittent renewable energy supply into a stabilised output.

FLASC started as an academic project built upon scientifc curiosity but has since attracted signifcant commercial interest.

Hydro-pneumatic liquid piston

Renewable energy sources deliver a power output that varies with tme. However, grids can only functon well when energy supply meets demand. The FLASC technology can be used to convert intermitent renewable energy supply into a stabilised output. This facilitates grid integraton by allowing the operator to schedule output at specifc intervals. Energy is stored using a hydropneumatc liquid piston, driven by a reversible pump-turbine. In charging mode, electricity is used to pump water into a closed chamber containing pre-charged air and in the discharging mode, the pressurised water is released through a hydraulic turbine to generate electricity.”

Commercialisation

The frst prototype was installed in 2017 in the Grand Harbour of Malta and in 2018, the concept was presented in the Start-Up Zone of the Ofshore Energy exhibiton. “Our appearance at the exhibiton caught a lot of atenton internatonally, with interest from many companies and organisatons, which is why we established a spin-of company later in 2019 to commercialise our technology”, Mr Buhagiar explains. “We decided to set up our company in the Netherlands and found a great opportunity to become part of the Buccaneer Delf community, which aims at acceleratng scale-up growth in the energy and ofshore industry. Apart from this, a lot of knowledge and experience is available in the Netherlands through the many companies and insttutes operatng in the ofshore energy industry, so it is really a great place to be for us.”

High effciency

According to Mr Buhagiar, FLASC HPES yields various advantages when compared with other existng energy storage devices. “Because of our unique closed pre-charged concept, the device can be used in shallow waters and can therefore work with fxed-

botom ofshore wind, whereas other solutons relying on hydrostatc pressure are beter suited to much deeper waters. It can also be used with foatng wind, installed within the foater or as a stand-alone plug & play soluton. A single centralised unit can also serve multple turbines across a windfarm. Compared to other energy storage systems using compressed air, the efciency of FLASC HPES is substantally higher. Systems that use compressed gas to store energy tend to sufer from low thermal efciency as the gas heats up signifcantly during compression. Our system mitgates this by limitng the pressure variatons as it operates and using the surrounding water of the ocean as a natural heatsink. The surrounding seawater quickly absorbs heat during compression and restores the heat during expansion. This results in a highly efcient soluton that operates at an almost constant temperature.”

Safe and reliable

Mr Buhagiar mentons other advantages, such as safety by design: the technology uses pressurised seawater and compressed air. None of the sub-components or materials are considered hazardous or fammable throughout their lifecycle. Wellestablished components are yet another beneft: despite its innovatve nature, the technology itself can be built with mostly of-the-shelf components, already wellunderstood and widely used in the ofshore sector. This also results in a high reliability and a long lifetme of more than 25 years, which can equal that of the ofshore windfarm itself. The lifetme is independent of the charging-discharging regime, an excellent match for intermitent renewables. “These advantages were also noted by the jury, when last October we were awarded the Best Innovaton Award at the annual Ofshore Energy event in Amsterdam”, he explains.

Subsea7

Building on the frst proof-of-concept prototype campaign, DNV GL were also brought in to review the technology, and ofcially granted the system a statement of feasibility. “Looking forward, the high capital costs and signifcant infrastructure necessary to upscale ofshore technologies is the biggest challenge. With this in mind, it is necessary to establish strategic collaboratons with leading companies that can deliver the full scope for large-scale installatons. This is why we are very pleased that we have been able to secure our frst collaboraton with Subsea 7. This is an important step towards the industrialisaton of our FLASC HPES technology.”

Many more applications

FLASC’s ambiton reaches beyond the conventonal wind energy market, as the FLASC HPES concept can be used in many more applicatons. The concept could also be useful in ofshore green hydrogen producton as an interface between wind turbine and electrolyser. Other applicatons include ofshore photovoltaics (PV), liquefacton of natural gas (LNG), liquefacton of CO2 for carbon capture and storage and seawater desalinaton. “These various applicatons highlight a fexible soluton, and we are eager to engage in feasibility studies on various applicatons. FLASC started as an academic project built upon scientfc curiosity but has since atracted signifcant commercial interest. We are now seeking to establish further collaboratons and engage with investors to take the company to the next level”, concludes Mr Buhagiar.

i. www.offshoreenergystorage.com

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