Subsea Hydrogen Long Duration Energy Storage

Abstract Nations around the world are progressing in adding renewable sources of energy to their grid as an attempt to meet CO2 emissions targets and provide power to increasing demand. The higher portion of intermittent renewables like solar and wind to the electrical grids have created a need for technologies that can not only provide resilience to the grids, but also have low greenhouse gas footprint. Long Duration Energy Storage (LDES) technologies are currently under development to fill this gap. Of the many LDES technologies, Hydrogen based systems is proposed as viable energy storage system for very long periods, including interseason periods, where hydrogen is stored in salt caverns. In this paper we describe an alternative LDES system based on hydrogen, where hydrogen is stored in pressure vessel at the seabed. Subsea storage provides a safe location for a large mass of hydrogen to be stored at a stable temperature environment, while requiring a reduced footprint on land, and providing geographic flexibility. The subsea hydrogen LDES system can fit a space where power can be provided for 10-100 hours, or more depending on the application, and by so, performing an economical mean to integrate renewables to a grid, or to enable a full renewable based grid to be sustained in isolated islands.