Renewable energy (RE) generation systems deployment is rapidly increasing globally, offering major advantages of reducing fossil fuel consumption and lowering greenhouse gas emissions to the environment. Renewable energy is by nature a sustainable resource which can prove cheaper energy production cost in the long term and enhance energy security. The recent development of renewable energy technologies showed a declining trend in terms of cost and advancement in the integration of RE resources to the existing power systems. The target of the electricity generation expansion plan in Oman is to reduce the dependency on natural gas as fuel and accommodate the Government's new fuel diversification policy. In Oman 2040 Vision, the future strategy in natural resource management will focus on developing non-traditional sources of natural resources, such as the use of renewable energy to reduce production cost and subsequently enhance the competitiveness of economic sectors. This objective aims to achieve 20% of renewable energy consumption compared with total consumption by 2030 and 35% to 39% by 2040. Oman benefits from a long coastline and exposure to the strong summer and winter monsoon winds. It has an average wind speed slightly over 5 m/s and an estimated 2463 hours of full load per year, making the wind power an economically viable form of renewable energy. On the other hand, Oman has a high ratio of "sky clearness" and receives extensive daily solar radiation. This makes Oman eligible for utilizing wind and solar energy as a sustainable and alternative source of energy. However, integrating Wind and PV economically into a conventional power grid necessitates the elimination of the complications caused by the intermittent behaviour of these resources. v Here comes the need to aggregate the output of wind turbines with the PV system and integrate the energy storage system (ESS) to waive the intermittency of Wind-PV and balance power generation. The hybrid Wind-PV-ESS Power Plant with a proper energy management system and well-designed control structure can achieve dispatchable RES, hence, improve the system reliability, reduce the intermittency of supply, and enhance the system security. The ESS can store extra produced energy and use it to compensate for the reduction in power generation and balance out the fluctuations of the wind-PV power in short and long periods. Additionally, the energy storage devices have a faster response to handle load variations and generation fluctuations as well as achieving a robust and dispatchable plant. To achieve this approach, a well-designed control system scheme must be constructed to connect all the components with each other and coordinate their operation. This thesis presents the proposed control system scheme along with its simulations and results analysis.