Abstract: Renewable energy integration focusses on incorporating renewable energy, distributed generation, energy storage, thermally activated technologies and demand response into the electric distribution and transmission system. . Energy Storage plays a key role in enabling a low-carbon electricity system. Energy storage can supply more flexibility and balancing the grid, providing a backup to intermittent renewable energy. It can improve the management of distribution networks, reducing cost and improving efficiency. Electrical power system is always subjected to different loading conditions. The load variation gives negative impact on the entire power system parameters. The assessment of transient stability is an essential requirement for the security of electrical power system This paper presents the simulation results of a transient stability and economic analysis with battery backup and ultra capacitor in grid connected operation