Flow batteries (FBs) are gaining traction as a long-duration energy storage solution, particularly suited to supporting zero-emission electricity from variable renewables.
A recent Faraday Institution report, Market and Technology Assessment of Flow Batteries for Developing Economies has assessed their viability in developing economies, comparing FBs to lithium-ion and lead-acid batteries.
FBs offer design flexibility, especially all-liquid systems where power and energy capacity scale independently. Hybrid FBs, which involve metal plating or gas generation, show higher energy densities but often lower current densities. Vanadium flow batteries (VFBs) lead on cycle life, with over 20,000 cycles demonstrated, while other chemistries require further validation.
Target discharge durations of 4–12 hours place FBs in direct competition with LIBs, with some designs aiming for up to 100 hours. Safety and temperature tolerance are key advantages, especially in regions with limited regulatory infrastructure.
Logistical challenges remain, notably low energy density and the need for localised electrolyte production. However, FBs can be transported in a discharged state, unlike LFPs. Maintenance demands vary by chemistry, and skill requirements beyond standard SCADA and electrical expertise remain a knowledge gap.
Manufacturing prospects are promising. FBs can be built at smaller scales than LFP facilities, lowering investment risk. Countries like India, South Africa, Thailand and Malaysia show strong potential, with opportunities to produce flow frames, bipolar electrodes and balance-of-plant components locally.
Flow batteries may not suit all applications, but for industrial, mining and off-grid island communities, they offer a compelling alternative – especially when paired with low-cost solar.
