Economic and energetic assessment of a hybrid vanadium redox flow and lithium-ion batteries, considering power sharing strategies impact

Abstract

Hybrid energy storage systems (HESS) combine different energy storage technologies aiming at overall system performance and lifetime improvement compared to a single technology system. In this work, control combinations for a vanadium redox flow battery (VRFB, 5/60 kW/kWh) and a lithium-ion battery (LIB, 3.3/9.8 kW/kWh) are investigated for the design of a HESS. A literature review presents the available energy management/power allocation options that are being studied and applied worldwide in batteries. There is an identified need for opportunities to address better HESS configuration's economic and energy perspective for building applications. The justification of investment in such HESS should improve indicators on use scenarios based on energy management compared to single-battery scenarios. In that context, four scenarios for real-time algorithms application approaches are considered to operate the hybrid storage solution through a 15-year economic and energetic analysis using experimentally validated battery performance models. The results obtained for each scenario are compared with a single technology battery performance to analyse this HESS pair competitiveness and the relevance of the power-sharing techniques among the different ESS technologies, which should be weighted. In the definition of the scenarios, real electricity generation is considered from two solar photovoltaic installations (3.2 kWp and 6.7 kWp) and an estimated representative load of a services building. HESS performance is evaluated through specific energy and economic key performance indicators. The results indicate that using customised energy management strategies (EMSs) renders the VRFB and LIB characteristics complementary, besides enhancing the competitiveness of VRFB as a single technology. Moreover, the HESS management impacts the seasonality factor, contributing to the overall electric system smart management.