Alexander Gitis

Applications and Markets for Grid-Connected Storage Systems

Grid-connected storage systems can deliver a variety of services; ancillary services such as frequency control divided into instantaneous, primary, secondary, and tertiary reserve, black start capability, uninterruptible power supply (UPS), self-supply, peak shaving, load shifting, and others. For some of these applications markets already exist and for others it has yet to develop. In most cases the development of a market is not as much a technical question as a matter of technoeconomics. Today most grid services are provided by the conventional power system components—only a few as for example UPS, black start capability, and island systems are already established domains of storage system. The situation is expected to change with the increasing share of fluctuating renewable sources in the power system. With the diminishing share of dispatchable power generation the system services have to be sourced elsewhere. At the same time battery storage technologies have made enormous progress in cost reduction, mostly driven by the mobile communication and IT sector as well as more and more the electric mobility sector, which starts to drive the cost reduction further. At this situation many applications are being discussed and new business models are being developed. Even the nomenclature of applications is still developing and definitions still vary from one author to another. In this chapter a selection of the main groups of application is presented and discussed with respect to market situation, application characteristics, system requirements, and barriers to market entry.

The propagation of horizontally polarized shear waves in plates bordered with viscous liquid

Requirements for ultrasonic horizontally polarized shear waves based viscosity sensors and their applicability for continuous in-line measurement are presented and discussed. The results reveal, that sensors using non-piezoelectric plates as well as wave guides and sensing surface have application-oriented advantages in corrosive and hot liquids. For such non-piezoelectric plate sensors, the dispersion relations are found and the linking equation among propagation velocity as well as attenuation coefficient and Newtonian liquid parameters are obtained. The findings show that in presence of viscous liquids the propagation parameters of horizontally polarized shear waves (HPSW) in non-piezoelectric plate change and a viscosity depending attenuation occurs. It is shown that the measurement sensitivity, in physical terms, of the investigated device highly depends on plate thickness, shear wave impedance of the plate material, and the shear wave impedance of the ambient liquid. Further, reasonable geometrical optimizations and suited plate materials are discussed.