In this paper, we consider two OFDM-based cellular systems, which can purchase the energy from the renewable energy resource and the conventional grid. And the base station (BS) with sufficient renewable energy can share its energy with the other one. Specifically, we study the scheme of resource allocation and energy management that minimize the sum-cost of the two systems. Under the constraints of the harvested energy of BSs and the target rates of the mobile terminals (MTs), a mixed integer programming problem is formulated. By using a suboptimal subcarrier assignment algorithm with low complexity, the strategy of power allocation, energy purchase and energy sharing is obtained based on the convex optimization theory. Numerical results demonstrate that the total energy consumption of the two systems can be decreased with the proposed resource allocation and energy management scheme.