VRBs can support the efficient functioning of the electric grid. One of the unique benefits of VRB flow technology is the ability to respond very quickly and supply energy for long periods of time. The high penetration of intermittent renewable energy, like wind turbines and solar installations, has resulted in the need for fast responding energy sources to balance the rapid variability of generation. Fast responding natural gas turbine “peaker” plants are currently used for this purpose. However, the VRB can provide a faster, more accurate response – with virtually zero emissions. Recent studies have estimated that energy storage could reduce emissions from such services by 70%. California Independent System Operator (CAISO) has estimated the need for 2,000 MW of fast ramping storage, with at least 2 hours of energy, in order to integrate a 33% share of renewable energy into the total electricity production mix by 2020. In addition, high penetrations of solar photovoltaics (PV) are causing significant problems on many utility distribution circuits. In some cases, solar PV contributes over 50% or more of the energy at certain times of the day. This high penetration can create repeated and severe voltage variations due to moving cloud cover. Moreover, the fast ramps of generation in the morning and evening are an issue, plus the problem of thermal loading as circuits designed for one-way power sometimes experience over generation. The VRB can help integrate solar into the distribution circuit by acting as a shock absorber, rapidly responding to generation ramps, supporting voltage, supplying reactive power and avoiding thermal overload. CAISO and the electric utilities are currently designing programs and tariffs to utilize the unique benefits of energy storage.