Flow Batteries

Basic Technology Characteristics
How it Works:	Liquid anode (anolyte) and cathode (catholyte). Electrolytes flow through reaction cell and charge transfer occurs at a membrane. Vanadium-based chemistry is most mature, other chemistries being developed.
Benefits:	Power (reactor size) decoupled from Energy (tank size) Limited impact of cycling on degradation Higher fire safety than lithium ion
Challenges:	Lower energy density Potential environmental spill risk OK to poor efficiency observed to-date Added system complexity with pumps etc.
Technology Variations:	Vanadium Redox Zinc Bromine Coupled iron-chrome Zinc/Chlorine Organic
Applications:	Energy shifting for renewable integration, T&D deferral, potential for longer duration
AC RTE Efficiency:	50-75%
Cycle Life:	20 years, >100,000 cycles (claimed)
Technology Readiness Level (TRL):	8 - deployed (for Vanadium redox). Early deployment / continued R&D.
Installed Capacity:	~100 MW