Prototype Floating Platform for Renewable Energy Storage to be deployed in the Grand Harbour

Offshore renewable energy technologies will be a key component of a future energy economy. However, a number of technical challenges remain, specifically the mismatch between renewable energy production and consumer demand for electrical energy.

Large-scale integration of electrical energy from renewables into the grid is challenging because of the intermittent nature of the resources. At times, there will be more renewable electricity than required, and in these cases the electrical energy will go to waste. At other times, there will not be enough to meet demand and conventional power plants must compensate. Energy storage addresses this mismatch by storing excesses to account for deficits in the supply and demand chain.

When it comes to storage one normally thinks of batteries, however, these are not viable at large scale, and especially in the offshore environment. An interesting method for large-scale energy storage is the use of compressed air. To charge the system, air is pumped into a closed chamber when a surplus of renewable energy exists. The compressed air is released from the system and passed through a turbine to recover the energy at times of high demand. A key challenge to this approach is managing the wide pressure and temperature changes taking place during the charging and discharging cycle.

The University of Malta is presently working on project FLASC: Floating Liquid-piston Accumulator using seawater under compression. FLASC is a novel concept for compressed air energy storage. It uses a dual chamber approach to eliminate wide pressure and temperature fluctuations. The technology is integrated into a floating platform that can support a number of offshore systems including wind turbines, floating PV, wave and tidal systems as well as oil and gas processes. This concept was developed by Dr Ing. Daniel Buha- giar during his Ph.D. research under the supervision of Prof. Ing. Tonio Sant.

Prof. Sant and his team at the Department of Mechanical Engi- neering are currently focusing on the construction of a small-scale prototype, to be deployed later this year in the Grand Harbour. The aim is to verify the concept in the field and to gain practical insights into the performance of the system in order to validate existing computational models. Development of the prototype is being carried out in partnership with Medserv plc with support from the Institute for Sustainable Energy of the University of Malta. This ongoing research will be presented at this year’s Offshore Energy and Storage (OSES) conference to be held in the United States. Project FLASC is financed by the Malta Council for Science and Technology (MCST) through the FUSION Technology Development Programme: R&I-2015044-T. FLASC is patent pending: PCT/IL2016/050100