Further details about the Vanadium Redox Flow Battery
The Vanadium Redox Flow Battery (VRB) used at the ' t Spieker Photon Farmer project at Vierakker has two poles, just like a normal battery. The system consists of two vessels filled with a vanadium-based liquid electrolyte. One side is negatively charged, the other is positive. The liquid is pumped through electrochemical cells where it either acquires or delivers a charge, depending on whether the battery needs charging or discharging. The main benefit of the VRB is its longevity. The manufacturer claims that it can operate for at least 12,000 charge-discharge cycles before battery capacity starts to deteriorate. Other rechargeable batteries have much shorter operational lifetimes, and cannot withstand deep discharge conditions (something that is not a problem for the VRB). Accordingly, VRBs can be expected to run for around fifteen years without any loss of performance. At the end of this period the vanadium needs to be replenished, after which the battery can be used for another fifteen years. In addition, the vanadium can be recycled, and battery capacity remains at optimum levels up to the very end of its operational lifetime. This, together with a smart monitoring and control system, gives the best possible yields from solar energy. A small computer controls the VRB’s behaviour, directing the charging and discharging processes to make the best use of the solar power generated and of the link with the national power grid.