Increasing the efficiency of an electric power system with cleaner productions is important for the fastest growing power industries. In this paper, hydro and wind renewable energy sources are considered to determine the optimal coordinated generation mode with high energy efficiency. In the proposed approach, the power efficiency is studied based on the quantification of economic benefits in the generation process. The economic benefit evaluating method is calculated by considering necessary items such as the regular operational cost, hydro regulation cost, power loss cost, plant investment and generation profit. From the operator's viewpoint, the mathematical expression of the hydro regulation cost is innovatively presented in the proposed method. To achieve the efficiency analysis, a new hydro-wind hybrid model is established using MATLAB/Simulink, which overcomes the previous limitation on data dependencies. Three real operating challenges, including the fluctuation of wind speed, the price volatility in market, and the influence of wind power permeation, are considered to reflect the relationship between the uncertain operating condition and optimal coordinated generation mode. Simulation results highlight the impact of real operating challenges on the hydro regulation cost, generation benefit and energy efficiency in the hybrid power system. The proposed model and method will result in a system with high efficiency and improved financial condition. Meanwhile, it will also benefit the policy development of renewable energy-based power industries.