ANNOUNCEMENTS
There is an increasing need for long duration energy storage technologies with the increasing renewable energy penetration of the grid. The current state of the art storage technology is the lithium-ion battery, which is not suitable for storage durations over 6 hours. The supply of lithium is also constraint to geopolitical issues due to its limited availability. In this project, sustainable energy storage technologies based on cheap, locally available materials are explored. Over 40 technologies were analyzed and 6 of them were shortlisted based on target parameters decided from a renewable energy project developer’s point of view. The following technologies were shortlisted: Room temperature sodium sulfur battery; sodium ion battery with Prussian White and Hard Carbon electrodes; Iron flow battery by ESS Inc.; Iron air battery by Form energy; liquid metal battery by Ambri; and thermochemical energy storage in nanocoated calcium hydroxide. An overview of these technologies is given followed by calculations of their Levelized Cost Of Storage (LCOS) for 100MWh capacity to work with a solar plant. The calculations were made based on costs estimated for the year 2025, which is the time when these technologies are expected to commercialize. It was found that the LCOS for all of these technologies is expected to be less than that of lithium-ion batteries. The LCOS calculation for thermochemical storage technology could not be done due to limitations of the LCOS calculation model which is currently only suitable for battery technologies.
Further, a sensitivity analysis of the LCOS was done to study the relationship between the various battery parameters and the LCOS. The analysis was performed on all of the shortlisted technologies (except thermochemical storage). It was found that the LCOS has a linear or nearly linear relationship with the Cell cost/kWh; Round trip efficiency; Depth of Discharge; and technical availability. It was found that there is a drastic reduction in LCOS when plotted against cycle life. However, it was also found that the LCOS reaches a low plateau upon reaching a cycle life of 9000, as there is no significant change in the LCOS upon further increasing the cycle life, this is mainly attributed to elimination of replacement costs as the lifetime of the battery reaches 25 years (average lifetime of solar projects) at a cycle life of 9000 for one cycle operation per day.
Keywords: Energy Storage; Sustainable Energy Storage Technologies; Long Duration Energy Storage; Levelized Cost Of Storage; Sensitivity analysis.
