Lithium-ion battery, sodium-ion battery, or redox-flow battery: A comprehensive comparison in renewable energy systems

Battery energy storage systems (BESSs) are powerful companions for solar photovoltaics (PV) in terms of increasing their consumption rate and deep-decarbonizing the solar energy. The challenge, however, is determining the effectiveness of different BESSs considering their technical, economic, and ecological features. To this end, this paper presents a bottom-up assessment framework to evaluate the deep-decarbonization effectiveness of lithium-iron phosphate batteries (LFPs), sodium-ion batteries (SIBs), and vanadium redox batteries (VRBs) in PV applications. The optimal size of the BESS has been determined and evaluated from technical, economic, and environmental perspectives. We also propose two new metrics, the levelized carbon emission of the battery and the levelized carbon emission of electricity, to calculate the environmental impact of BESS. Later, we conduct the economic-ecological-efficiency analysis to find the BESS that could bring the most environmental benefits at the lowest cost. The results show that VRBs can compete with LFPs at the current price. Although SIBs are not yet competitive with LFPs due to their shorter lives and higher costs, they have the least environmental impact at 64 g CO2/kWh and the shortest carbon payback period of 1.4 years, indicating their potential in the future.