Abstract: Power-energy balance and peak regulation method is presented to adapt to the new energy development in power system planning. Firstly, with the convergence condition of given LOLE value, the power-energy balance is obtained by the convolutional integration of probability-distribution functions of the output of thermal and new-energy plants. Secondly,the over-supplied indices is also presented and used to evaluate the peak regulation capability of power system and the abandoned new energy in the case that all thermal plants are in their minimum technical capacity. Case studies show that the presented method is suitable for the variable-output of new-energy generators, which can evaluate their capability-effects correctly. The presented peak regulation method is more necessary in power system with rich new-energy, because the energy is abandoned so frequently for variable-generations.