Flow Batteries : Has Really Large Scale Battery Storage Come of Age ?
The market for electrical energy storage (ES) solutions has been mostly limited to relatively small applications of battery uninterruptible power supply systems (UPS’s) and very large site-specific systems such as pumped hydro storage, two completely different types of ES with separate markets. Flow batteries (FBs) are promising to change that by providing a technology that can potentially span this entire range of applications. Flow batteries have demonstrated providing ES from sub-second local power reliability to hourslong load shaping and price arbitrage functions at the large commercial end-user-scale (500 kW, 520 kWh). Several pilot plants have been built at this scale and early results are positive. In addition, pilot utility-scale systems (12 megawatt, 120 megawatt-hour) are being constructed. The scale and variety of these pilots reflects high confidence in this technology by developers. This paper details technical principles of 2 competing flow battery technologies available in the immediate future, compares their market-readiness, and analyzes economics and market potential for this technology to compete with UPSs as well as play into new commercial load management markets.
A field trial of a Vanadium Energy Storage System
This Paper describes the establishment of a Userbased field trial of a Vanadium Energy Storage System (VESS) incorporating a 250 kW/520 kWh Vanadium Redox Battery (VRB). The trial is significant in that the system is the first commercialscale VRB installation outside Japan.
A new power measuring circuit using a bridge-connected magnetic circuit and another magnetic core
The authors describe the operating characteristics of an oscillating circuit using a bridge-connected magnetic circuit and another magnetic core. A square-shape output voltage is obtained in the oscillating circuit. The pulsewidth in positive and negative half cycles of output voltage changes with the current of the U-form core windings and with the signal voltage applied to the exciting windings. The mean value of the output voltage varies in proportion to the product of the current and the signal voltage. Utilizing this feature, an application of the oscillating circuit to a novel power measuring circuit of simple construction is presented. >