In the past, canals were the main logistics artery. Today, they no longer play such a role, becoming a quiet waterfront through which ships occasionally pass. Here, as a proposal to actively utilize the canal, we examine the potential of tidal power generation using the difference in water levels between the inside and outside the canal basin caused by the closure of sluice gates. If the canals have already been equipped with sluice gates, we recommend making effective use of them. In the case of canals where gates have not yet been installed, it is proposed to install self-elevating gates without support columns that do not obstruct the passage of vessels. As a concrete example, the Keihin Canal in Tokyo Bay was studied. An estimation of the amount of electricity generated was presented assuming several variables, including tidal range, turbine specifications, and water area. With the optimal number of turbines installed, the canal can become a valuable source of energy, such as an emergency power source in case of a power outage in the event of a disaster. Furthermore, the electricity generated can also be used as an independent power source to open and close the sluice gates. Thus, the effective use of canals is expected to create new synergies between disaster prevention and renewable energy development in urban waterfronts.