Environmental and Performance Assessment of Lithium-Ion and Flow Battery in Hybrid Renewable Energy Systems

Abstract

Reliable and affordable electricity remains critical for rural development in regions where grid expansion is constrained by high costs, difficult terrain, and dispersed settlements. Hybrid Renewable Energy Systems (HRES) that integrate solar, wind, and energy storage provide a viable decentralized alternative, with rural Kenya offering representative deployment conditions. In this study, Imbirikani in Kajiado County, Kenya, was selected as a case site because of its alignment with typical off-grid microgrid contexts. This study compares lithium-ion (Li-ion) and vanadium redox flow battery (VRFB) energy storage technologies within HRES deployed in rural Kenya, using HOMER Pro for techno-economic simulations, and cradle-to-grave Life Cycle Assessment (LCA) following ISO 14040/14044, and Analytic Hierarchy Process (AHP), based multi-criteria decision analysis (MCDA) was used. The results indicate that Li-ion systems achieved a lower Levelized Cost of Storage (LCOS) of KSh. 23.17/kWh compared to KSh. 28.32/kWh for VRFBs, primarily driven by higher round-trip efficiency and lower upfront capital costs. However, Li-ion systems exhibit higher Global Warming Potential (GWP) impacts of 0.18 kgCO₂/kWh, relative to VRFBs’ 0.10 kgCO₂/kWh, largely attributable to lithium–cobalt extraction and limited end-of-life recyclability. In contrast, VRFBs demonstrated longer cycle life, full depth-of-discharge capability, and electrolyte recyclability exceeding 80%, thereby supporting improved long term environmental performance. The study contributes an integrated techno-economic, environmental, and decision-analysis framework for evaluating energy storage technologies in rural African micro grids. Therefore, it is evident that, the multi-criteria evaluation highlights Li-ion batteriesas the preferred option for near-term, cost-driven rural micro grid deployment in Kenya, while VRFB technologies are recommended for long-term sustainable energy planning where lifecycle, durability and environmental performance are prioritized.