Battery storage: Comparing shared to individually owned storage given rural demand profiles of a cluster of customers

In many low-income settings and geographies it´s not immediately feasible to deploy central power generation with electric grids. In this context, off-grid approaches like solar home systems (SHS) are gaining wide acceptance. Since battery storage costs are the dominant costs, the value proposition of using a novel mini-grid with shared generation/ storage as opposed to SHS is examined. The relative merits are evaluated using time-resolved demand data from a cluster of small rural consumers. During the two-year operation of 9 SharedSolar systems in Uganda, nearly all the electrical demands were met as the systems were oversized for initial demand. This allowed us understand the actual demand (under commercial tariff payments) and estimate supply reliability for smaller optimal storage sizes post facto. Using real time data, storage characteristics and HOMER simulations, optimal sizing for both approaches were established. The analysis reveals that customer diversity leads to considerable savings in storage requirements for same reliability when a shared approach is utilized. The study informs helps informs the economics of providing off-grid access to electricity.