- Vanadium redox flow batteries (VRFBs) offer the advantage of decoupling power output and energy capacity
- RFBs have the capacity to provide more energy over their lifetime, resulting in a lower levelized storage cost (LCOS) than Li-ion batteries
Redox Flow Batteries (RFB) usage has increased in the last few years. A report by IDTechEx says that the RFB market will be valued at US$2.8B by 2034. There are several factors that will determine how the RFB market will grow over the coming decade.
RFB has been used widely for large, grid-scale applications for stationary energy storage. As more significant volumes of Variable renewable energy (VRE) sources penetrate electricity grids, there may be more extended periods where these sources of energy are not available. Hence, energy storage technologies that can provide longer storage durations, such as RFBs, will be needed to dispatch energy over these longer timeframes.
There are a number of RFB manufacturers who claim that their systems have a high cycle life. In some scenarios, 20,000+ cycles, which is much higher than Li-ion batteries. It means that RFBs have a capacity to provide more energy over their lifetime, resulting in a lower levelized storage cost (LCOS) than Li-ion batteries.
Vanadium redox flow batteries (VRFBs) offer the advantage of decoupling power output and energy capacity. To boost energy capacity, simply enlarge the electrolyte storage tanks and volume. Adjustments to the cell stack become necessary only when aiming for higher RFB power output.
Despite these advantages, the CAPEX per kWh of VRFBs is currently higher than Li-ion batteries, and the cost of vanadium electrolyte limits cost reductions. Moreover, as there is not currently a great demand for LDES technologies, RFBs will compete with Li-ion for grid ancillary and utility services in the current stationary energy storage market. These applications will typically be for 4 hours of duration or less, for which Li-ion is already a more widely deployed, well-understood, and commercially viable technology. Therefore, RFB growth over the next few years is expected to be steady and made up of pilot and demonstration projects.
RFB manufacturers are keen on cost reduction via enhanced manufacturing methods and exploring cost-effective RFB chemistries. Additionally, they seek to scale up their systems, showcasing their capability for long-term energy storage. For instance, ESS Inc. intends to deploy a 500 MWh all-iron RFB with a 10-hour duration in Germany by 2027. The outcomes of such ventures are pivotal in driving further expansion in the RFB market.