Studying the Effect of Decentralized Battery Storage to Smooth the Generated Power of a Grid Integrated Wind Energy Conversion System

This work investigates the technical possibility of using battery storage in order to smooth the power generated from a grid connected wind energy converter unit. Wind energy has gained much credit in the past two decades as a sustainable energy resource. The penetration of wind energy generators into the electric utility grids is expected to increase to about 203.5 GW within the present decade. Due to the intermittent nature of the wind and the limited reliability of the wind prognoses there have been serious concerns about reliability and operation of the utility power grids. Battery storage is suggested to compensate wind power fluctuations and smooth the power flow to the utility grids. The battery storage in such applications has dynamic operating conditions and is subjected to different degradation mechanisms which stimulate the capacity losses and hence influence the feasibility of their implementation. In this paper, the real behavior, the technical feasibility of the battery and its effect on wind power fed to the utility grid will be judged. The investigated system is simulated using real measurement data of a 600 kW rated power wind turbine. The simulation results of different battery capacities show that the integration of the battery storage has compensated the fluctuations of the generated wind power to match the forecasting value, which smoothed the power fed to the utility grid and allows better grid operation. Moreover, the battery aging model has generated very important information about the battery degradation and available capacity (in this case of about 85%) after one year of operation. Therefore, further investigations with different battery technologies (e.g. Li-Ion and NiMH) and development of intelligent system operation strategy have to be investigated

PVA-PDMS-Stearic acid composite nanofibrous mats with improved mechanical behavior for selective filtering applications

In this work, we report a facile way to fabricate composite nanofibrous mats of polyvinyl alcohol (PVA), polydimethylsiloxane (PDMS), and stearic acid (SA) by employing the electrospinning-technique, with PDMS fraction ranging from 40w% to nearly 80w%. The results show that for a predetermined fraction of PVA and SA, incorporation of an optimal amount of PDMS is necessary for which the mats exhibit the best mechanical behavior. Beyond this optimal PDMS fraction, the mechanical properties of the composite mats deteriorate. This result has been attributed to the ability of the SA molecules to mediate binding between the PVA and PDMS long-chain molecules via van-der-Waals bonding. The morphological, structural, mechanical, and thermal characterizations respectively using SEM, XRD, DMA/tensile test, and DSC lend support to this explanation. By this method, it is possible to control the hydrophilicity/oleophilicity of the mats, and the mats show an excellent selective permeability to oil as compared to water and successfully filter water from a water-in-oil emulsion. Incorporation of SA not only serves to aid in electrospinning of a PDMS-rich nanofibrous mat with good mechanical strength and control over hydrophilicity/oleophilicity, but also has a potential use in fabricating sheets impregnated with phase change materials for thermal energy storage