Before revision:  Under certain settings, we show that CHASE achieves the best competitive ratio of all deterministic online algorithms . We also extend our algorithms to intelligently leverage on limited prediction of the future, such as near-term demand or wind forecast. By extensive empirical evaluation using real-world traces, we show that our proposed algorithms can achieve near-offline-optimal performance. In a representative scenario, CHASE leads to around 20\% cost savings with no future look-ahead at all, and the cost-savings further increase with limited future look-ahead.
After revision:  Under certain settings, we show that CHASE achieves the best competitive ratio of all deterministic online algorithms , and the ratio is no larger than a small constant 3.