We propose a real-time control algorithm for energy storage management with renewable generation integration. We formulate the control optimization problem to minimize the system cost over a finite time horizon. Our model assumes arbitrary dynamics of renewable generation, load, and electricity pricing and incorporates battery operation costs into the system cost. We apply the Lyapunov optimization technique to design the real-time control algorithm. Different from the infinite time horizon problems in the existing works, the coupling of control decisions over time, due to finite battery capacity, is more challenging to manage. We develop a new technique to tackle this issue for real-time control. The proposed algorithm is shown to have bounded performance from that under the optimal non-causal T-slot lookahead control policy.