The Internet explosion makes energy con- sumption of the ICT sector a global concern. Nowadays, the power consumption of access net- works increases rapidly due to the rollout of broadband services. Cable access networks pro- vide Internet access over the existing cable tele- vision systems. Among all wired access networks, they have the second biggest user base, which is still growing fast due to the release of the new industry standard, DOCSIS 3.0. Therefore, we expect that cable access networks will play an important role in the ICT sector of future smart cities. In order to boost up bidirectional through- put, DOCSIS 3.0 introduces the channel bond- ing technology, which could lead to increased power consumption if not properly managed. In this article, we present a few energy-saving algo- rithms that could be used by the cable operators to improve the energy efficiency of cable access networks using channel bonding. The discussions cover both the network-wide energy-saving algo- rithm and the customer-side energy-saving algo- rithm, and provide investigations on the trade-offs between energy-saving and other net- work performance metrics, including packet delay and protocol overhead. Our numerical results suggest that effective energy saving can be achieved in wideband cable access networks with the proposed algorithms, and the packet delay and protocol overhead can be reduced if we choose the key parameters properly.