Battery & ultra-capacitor based energy storage vessel integration, capabilities, considerations and challenges

Energy storage has been successfully used in numerous sectors, such as the automotive industry, and it is only recently that the benefits of advanced energy storage technologies are being considered or realised for marine vessels. That said, it should also be noted that some types of marine vessels are taking the lead in exploiting these technologies to bring real benefits to the vessels’ operational profiles and capabilities. The main exploiters of these ‘new’ energy storage opportunities are ferries, mainly due to their operating profile which currently aligns with battery utilisation, charge and discharge characteristics. This has resulted in maturing of the marine sector energy storage technologies and topologies, increasing confidence and increased exploitation advantages. These advantages are also applicable to different vessel platforms such as drilling and naval platforms, bringing operational benefits, new modes of operation and integration challenges. This paper will provide an overview of energy storage systems and describe current capabilities in terms of kW and kWh, and provide readers with considerations when integrating energy storage into marine vessels. Considerations will include types of applications, from high power, short duration to sustained power, long duration, and will describe the analysis required to optimise the energy storage asset and ensure adequate power system performance in terms of operational and common mode considerations when using pulse-width modulation (PWM) converters connected to battery or ultra-capacitor based energy storage systems. Common mode effects should not be overlooked as, if not duly considered, can lead to significant electro-magnetic compatibility (EMC) issues