Abstract: The increasing penetration of renewable energy implies significant changes into the features, analyzing methods and coping strategies of power system balance issues. The reliable supply of customers and the utilizing of clean energy would be more difficult due to the uncertainty of renewable energy output in respective time scales. Considering the accuracy of renewable energy prediction and the expectation of the power dispatching objectives both increasing gradually with the shortening of the time scale, this paper specifies a power and energy balancing procedure using progressive decomposing techniques to provide optimal dispatching strategy so as to fulfil the reliable customer supply and the minimum curtailment of the clean energy. An actual planned power system with high penetration is studied in panoramic view as an example scenario afterwards to find out power and energy balance problems in various time scales: annually, monthly, weekly and daily. Challenges faced by dispatching agencies in the scenario are mainly depicted and some suggestions are introduced as potential solutions, including the coordinated allocation of adjustable resources, the diversification of unit maintenance strategy, the power trade strategy and the supplementary power market regulations.