System Characteristic And Optimization Study Of Seawater Pumped Hydro Energy Storage

Energy storage technology is one of the most important technologies to build a clean,low carbon,safe and efficient modern energy system.Pumped hydro energy storage,which has the merits of mature technology,high efficiency and capacity,long storage period,is a large-scale energy storage technology which has been widely used.Seawater pumped hydro energy storage(SPHES)utilizing seawater as upper or lower reservoir,has the advantages of abundant water supply,small variation of water level,and low construction cost.It solves the dependence of PHES to fresh water and has a broad prospect for coastal cities and islands which lack of fresh water.Currently,researches about the performance characteristics of SPHES system,as well as its integration with the renewable energy generation system,are rarely conducted overseas.And there has been scant research reported on SPHES in China.The 13th Five Year Plan in Hydropower brings the research on SPHES into the key tasks,and requires to strengthen the research on its key technologies.In this paper,the hydraulic characteristic of SPHES was studied.And coupling characteristic and optimization analysis were carried out on the wind-solar-seawater hydro energy storage hybrid system.1.Energy conversion models of two kinds of SPHES were built and analyzed through MATLAB software.Based on which the hydraulic performance was studied.The influence of rotating speed,altitude and value opening on the systematical performance were revealed in this paper.2.The energy conversion model of the wind-solar-seawater hydro energy storage hybrid system was established.The simulation work was carried out using MATLAB software,and the simulation results reveal the change of the loss of load probability(LLP),energy excess percentage(EXC)and cost of energy(COE)along with the scale of each subsystem.3.A single objective optimization method,based on COE or EXC,and double-objective optimization method,based on COE and EXC,or COE and LLP,of the wind-solar-seawater hydro energy storage system were proposed.And the optimization model were established.A typical case study were carried out in single objective and double-objective optimization.And the optimal system configuration of single objective optimization and the pareto optimal solution of double-objective optimization were obtained.4.A sensitivity analysis on several key parameters of the hybrid system was also studied to examine their effects on system COE.The simulation results reveal the effects of several variable parameters on the COE.