Integration Of Renewable Energy Sources Into The Power Grid System With Energy Storage System

The power grid system(PGS)is composed of several generation power plants,trans-mission systems,and distributions,which supply electricity to domestic areas,commercial,agriculture,and industries through interconnected systems.However,in some regions,the distance between the communities is so far and the full-scale PGS is almost difficult to re-alize.Thus,there are smaller independent power stations that supply electricity to remote areas,which have no access to PGS because connecting these areas to PGS is expensive and in some regions physically is very difficult to build.Renewable energy sources(RES)are attractive sources of power which can provide sustainable energy,free cost because do not require any supply of fossil fuels and clean because do not have any emissions such as C02 which is the main causes of greenhouse emissions.However,the utility of RES needs an efficient energy storage system(ESS)to supply the power continuously and maintain system stability through the whole operation periods.Compressed air energy storage(CAES)is one of the most efficient ESS technologies for large scale PGS due to its some advantages such as easy installation,low maintaining costs,modular structure and running uptime.Advanced adiabatic compressed air energy storage system(AA-CAES)is a type of conventional CAES technologies has been developed for RES applications which can eliminate the use of additional fuel input in conventional CAES systems by utilizes the excess power produced by RES or the electricity comes from PGS during the off-peak periods to store air and reused it when needed.In this thesis,the integration of RES into the PGS with ESS is presented.Nyala city in Sudan has been chosen as a preferred wind farm location because the power supply by the existing diesel power plant is expensive due to high costs for fuel transport and the reliability of power supply is low due to uncertain fuel provision.At the side of renewable generation,the modeling and simulation of the wind turbine is presented to investigate the performance evaluation of the turbine system and the results show that the wind speed and the turbine blades area are plays an important role in increasing the power generation by the wind turbine.Firstly,the modeling of a wind farm(WF)with AA-CAES integration is introduced to investigate the behavior and characteristics performance of the system in terms of thermodynamic analysis during the compression and the expansion cycles.The results show that the wind speed,final storage pressure,and the air flow rate are the key factors to increase both the amount of energy storage in the cavern during the compression cycle and the amount of power generation during the expansion cycle as well as improving the system efficiency.Secondly,the optimization problem which composes of diesel power generation(DPG),WF and CAES have formulated as security-constrained unit commitment(SCUC)problem with mixed-integer linear programming(MILP)aiming to maximize the power generation and minimize the fuel consumptions.There are three scenarios are examined to determine the commitment and dispatch of units.In the first scenario,it's assumed that there is no RES and CAES in the system which the load demand is only supplied by DPG and the results show that the cheaper units are always committed to supplying the load demand.In the second scenario,the RES is added to the system and the results show that more expensive diesel units are not committed to dispatching the power and only cheapest units are dispatch power with RES but there is a reduction of reliability and power quality for customers in the system due to intermittent nature of RES.In the third scenario,ESS is added to the system with RES to make balancing and maintain the system stability by storing the energy and reused it again when needed and the results show all the expensive diesel units are not dispatched power and the load demand is only supplied by the cheaper units,RES,and CAES.Finally,the formulation of SCUC for hybrid system contains DPG,WF,CAES and solar photovoltaic(PV)is introduced to determine the commitment and dispatch of units and the results show that more reduction in the generation cost and high system reliability is achieved.The model is coded in MATLAB which solved with solvers CPLEX 12.7.0 and GORUBI 8.0 and the final results show that the significant fuel saving can be achieved,reduce the car-bon emissions,suitable for the backup power system and peak shaping as well as helpful in the power system management and design.