An investigation into the use of the vanadium redox flow energy storage system for peak-shaving and load-leveling

[摘要] ENGLISH ABSTRACT:This thesis investigates the credibility of the vanadium redox flow energy storagesystem, sometimes termed vanadium redox battery (VRB). The focus is on theuse of this technology in peak-shaving and load-leveling applications. The initialproblem is to find a suitable mathematical model for representing the daily loadprofile. A sinusoidal function is identified as an elementary approximation of thefirst order. Due to the periodicity characteristics that are inherent in a daily loadprofile, the Fast Fourier Transform (FFT) algorithm is identified as amathematical model that closely resembles a load profile.The main theme in this thesis is the determination of an optimal solution duringthe peak-shaving process. In this particular context, the optimal solution refersto the following: With the energy capacity of the VRB and the power rating of theentire system considered as the constraints, the interest is on (i) the constantpower that the VRB can deliver in order to bring down the maximum demandquite significantly, (ii) and the time interval in which this constant power isdelivered. Therefore, the VRB power delivered during peak-shaving (PVRB) andthe corresponding time interval are the main two parameters under considerationin the optimization process.The mathematical algorithm that can be used to determine suitable values forthese two parameters is developed. Maple V 5.1 is used for determining thesolution analytically. The obtained results are verified by simulation with Excel.The investigation into the economic benefits that may be derived from theutilization of the vanadium energy storage device is also presented.

[发布机构] Stellenbosch University