Energy Storage for Floating Systems

A novel concept for large scale offshore renewable energy storage in deep sea has been developed by The University of Malta for the next level of technology development.

Currently, a huge progress has been made by the development of offshore renewable energy conversion technologies. However, although the advantages of this progress is obvious, wide scale penetration of offshore renewable energy sources remain hindered by a few challenges.  Due to intermittency, integration of electrical energy from renewables into the grid is difficult; therefore, a considerable amount of green energy is wasted.  On the other hand, renewable energy supply is not in phase with energy demand, therefore the energy sector remains heavily reliant on fossil fuel energy sources during peak consumption periods.

Right now, the development of cost-effective energy storage technologies is essential in order to allow the large-scale integration of renewable energy plants into the national grids.  Storage solutions can mitigate the supply-demand mismatch, which is inherent to practically all forms of renewable energy technology.  A number of storage technologies exist, each providing distinct advantages along with their own limitations.  One of the key issues is scaling up the storage systems to interface with multi-megawatt generation systems.  Conventional technologies such as battery banks are not yet feasible at this scale.

The University of Malta’s new concept consists of a floating structure with an integrated hydro-pneumatic accumulator to store pressurised seawater through compressed air.  Computer simulations conducted by PhD researcher Ing. Daniel Buhagiar have demonstrated the technical potential of the proposed system in smoothing fluctuations in the intermittent supply of renewable energy, overcoming issues associated with the integration of offshore-based technologies into national electricity grids.  The floating structure can additionally serve as a multi-purpose platform ideal for mounting renewable energy technologies and for supporting, maritime services offshore.