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58 www.resourceworld.com A P R I L / M A Y 2 0 1 6 ALTERNATIVE ENERgY REVIEW Developments in Alternative Energy by Jane Bratun new vanadium-flow battery Could have big impaCt unienergy technologies (UET) produces turn-key, large-scale energy storage sys- tems for utility, micro-grid, commercial, and industrial applications. At the UET system's core is an advanced vanadium flow battery, the Uni.System™, which is advertised by the company as safe, opera- tionally flexible, reliable, cost-effective, with a long life expectancy. The UET redux flow battery (RFB) is a unique electrochemical device that stores electrical energy in liquid electrolytes instead of in electrodes as many other bat- teries do. The RFB then releases the stored energy according to customer demands at levels up to multi-MW and MWhs. An RFB cell comprises two electrodes or stacks (made from carbon felt and other items) and two circulating electrolyte solu- tions (a positive cathode-side electrolyte or catholyte, and a negative anode-side electrolyte or anolyte) separated by an ion exchange membrane or a separator. The energy conversion from electricity energy to chemical potential energy (charge) and vice versa (discharge) occurs instantly within the electrodes as the liquid electro- lytes flows through the cell. The UET storage system provides buff- ering capabilities between bulk energy generation and subsequent energy use. Energy generated from variable renew- ables, as well as from other grid resources, is stored and then, when optimal for the grid and or at the micro-grid level, released for use. This buffering can be in many time scales, from less than a second, to hours, to days, and with multiple appli- cations run by the control system. Like UET's larger-scale Uni.System (500kWAC/2MWhAC), the newly released ReFlex uses UET's next-gener- ation advanced vanadium technology. According to the company, this technol- ogy has a proven safety record, with no thermal runaway risk and a flammability rating of zero. Each system has a 20-year life with no capacity degradation, and is environmentally safe and recyclable. The ReFlex controller includes a peak shaving application. Peak shaving is a pro- cess that shifts demand from peak times, for example, from noon, to times with lower demand – for example, night. This is done with devices that do not need to run immediately like washing machines. UET's Chief Operating Officer, Rick Winter, commented, "We've learned a tremendous amount from our utility cus- tomers and MW scale installations, which we've translated into truly robust plug and