The University of Malta has developed a novel concept for large-scale offshore renewable energy storage in deep sea, with researchers teaming up with Medserv plc. for the next level of technology development.
The development of offshore renewable energy conversion technologies is making significant progress. However, despite its obvious advantages, 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.
Currently 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, (such as a wind, solar or wave generators) and for supporting, maritime services offshore (for oil, gas and aquaculture industries).
Market assessments have clearly indicated that the proposed concept falls within high market demand and may offer significant benefits over existing and emerging technologies when realised. Project FLASC (Floating Liquid-piston Accumulator using Seawater under Compression) which is the next step, will involve the design and construction of a scaled, proof of concept prototype. The prototype will eventually be deployed in Maltese waters and measurement data will be used to evaluate the energy storage performance characteristics of the system when operating in a real marine environment. The project is being led by Prof. Ing. Tonio Sant, Head of Department of Mechanical Engineering. The industrial partner, Medserv plc., will provide offshore engineering expertise and handle logistical activities during the various phases of the project. The collection of measurement data will be supervised by Ing. Robert N. Farrugia from the Institute for Sustainable Energy. The acquired data will also be used to validate computer analysis tools developed in-house and in turn will eventually be used to design full-scale commercial systems.
Project FLASC is financed by the Malta Council for Science and Technology (MCST) through the FUSION Technology Development Programme 2016. (reference number R&I-2015-044-T).