Solar + Storage9 Sep 2019 08:27
https://solarbuildermag.com/energy-storage/stacks-on-value-stacks-the-large-scale-solar-plus-storage-is-coming-together/
Energy storage combined with solar PV can address a large number of traditional problems, such as energy issues — like time shift, arbitrage, curtailment, transmission congestion — and power issues — like frequency response, ramp rate control and renewables smoothing. Such value factors stack up to build a case of economic feasibility, but the key feature for large-scale is eight to 16 hours of storage, says (David) Stripling ( NEXTracker’s global manager of storage products).
“That duration is going to be the biggest opportunity for solar + storage over the next 10 years,” he reckons.
To achieve long duration and high cycle storage, or bulk storage, will require some combination of flow batteries, pumped hydro and compressed air. Of these, flow batteries seem to have the strongest lead, and among flow battery chemistries, vanadium may be the top contender.
The vanadium redox battery (VRB), also known as the vanadium flow battery (VFB) or vanadium redox flow battery (VRFB), uses sulfuric acid and water and can infinitely charge and discharge, returning to its original core state without degradation.