Design of hydrid electrical energy storage system for grid connected wind energy

Abstract

The aim of this thesis is to design and optimize a hybrid electrical energy storage (HEES) system to integrate wind energy into the grid. It explains why combining multiple electrical storage technologies in the integration of wind resources is preferable than employing a single electrical energy storage method. This thesis revised previous studies done on HEES system with wind resources and suggested areas for improvement. The HEES system suggested is composed by Liion battery, supercapacitor, and pumped hydro energy storage system. When wind resources are available, one portion of the energy produced by the wind generators are used by community, while the other portion is fed into the grid and the remainder is utilized to charge the storage systems. When the wind resources are not available or enough to produce the required power, there is always a power fluctuation in the network, then the energy stored in storage devices can be used to alleviate those variations. Frequency control can be achieved with a supercapacitor, voltage drop compensation can be achieved with a Li-ion battery, and maximum supply demand can be met with pumped hydroelectric storage system. To solve the problem caused by wind variations, this thesis suggested a powerful algorithm which is Proprietary Derivative Free Algorithm (PDFA) to get the optimal size of Hybrid Electrical Energy Storage to handle this problem. The design data are simulated and analyzed using Homer Software, ETAP and Matlab software. After simulation the Hybrid Electrical Energy Storage presented a high impact in network with 98% -100 % voltage regulation at each bus bar and at PCC in network, improve the power factor at 99.17% in utility grid and satisfy the bulk power at 100%. The Hybrid Electrical Energy Storage has the positive economic metrics: The payback period of 3.12 years, net present value of 621654166.7$, internal rate of return of 31.7%, return on investment of 27.5% and levelized cost of electricity of 0.03477$/kWh. These economic metrics show that the Hybrid Electrical Energy Storage is economically profitable.