Improved PV system performance using vanadium batteries

Abstract

A vanadium-vanadium redox battery can improve photovoltaic system performance, reliability and robustness by increasing the energy conversion efficiency of the battery to 87%, by making the battery life, efficiency and ongoing energy capacity independent of state of charge and load profiles and by reducing maintenance requirements. High battery efficiency reduces the required PV while a battery life insensitive to battery usage relaxes system constraints. These advantages are utilised in a demonstration PV system in Thailand that was designed specifically to use vanadium technology. Following a 12 month field testing program with 4 kW vanadium batteries, 300 systems consisting of 2-4 kW PV, a 4 kW, 15 kWhr, vanadium battery and a 4 kVA grid interactive inverter are intended to be installed in residences in Thailand.