Energy Storage Coupled With an SMR for a Micro-Grid

Abstract

Canada has hundreds of communities and industrial sites that have standalone micro-grids to supply and manage electricity. These micro-grids are required to meet energy demand and provide back-up power during an emergency. Current back-up systems are most often fossil-fuelled generators that are kept on standby until required. Some small modular reactors (SMRs) under development are advertised as low-carbon alternatives for use on micro-grids. However, in order to maximize the economic competitiveness of an SMR it should operate as close to full capacity as possible. Therefore, SMRs are not suitable for back-up power on their own. This paper considers coupling an SMR with an energy storage system that could offer back-up power support to the micro-grid during an outage. Three energy storage technologies were considered in this analysis: battery energy storage (BES); compressed air energy storage (CAES); and hydrogen energy storage (HES), with the following outcomes: • None of the energy storage technologies could offer an economically competitive back-up power solution. • Utilisation factor is the underpinning parameter for the viability, that is if these are used only for back-up power, then economic viability is very low, but the utilisation factor could be increased by allowing the back-up power system to be used for micro-grid load levelling services. • Both CAES and HES systems could be suitable for long-term SMR outages (from a week to a month), the CAES is more suitable among these two. • The batteries (BES) were found to be not suitable in any storage or SMR size scenarios assessed, as the inherent self-discharge characteristics reduces the battery efficiency significantly when not used over a long-period of time. • None of the energy storage options are suitable for ‘1 day’ back-up (the lowest operating frequency or utilisation factor) making it very difficult to recover the costs. Keywords: Small Modular Reactor, Hydrogen, Batteries, Compressed Air, Storage, Remote Communities, Micro-Grids.