Design of a solar island with a water-battery storage system for Lake Ziway islanders in Ethiopia

Access to reliable electricity remains a challenge for millions in remote African villages, including Lake Ziway’s islands in Ethiopia. This study introduces an integrated electricity system for Tulu Gudo Island, combining floating photovoltaics (FPV), pumped-hydro storage (PHS) and diesel generators (DGEs) to overcome energy constraints, land scarcity and sustainability issues.

The study assesses electricity demand and solar-PHS potential using LiDAR-based digital elevation model (DEM) data and Geographic Information Systems (GIS). PVsyst and HOMER Pro optimize the system based on net present cost (NPC), cost of energy (COE) and its ability to support a water-energy-food (W-E-F) nexus approach.

An optimized configuration with 32.2 KWp FPV and two PHS units (PH: 245 KWh (508 KWh)) meets Tulu Gudo Island’s energy needs through a cycle charging strategy (CCs). This configuration offers economic and environmental sustainability, with an NPC of $154,265 and a COE of $0.140/KWh, while conserving 8760 m3 of water.

It integrates successfully with the W-E-F nexus approach, achieving a 7% increase in electricity generation and a 2.4% higher capacity factor compared to conventional setups. The study validates results through comparisons with other simulation tools, ensuring accuracy. This hybrid electricity system has potential applicability in regions with similar conditions worldwide.