2021 Volume 77 Issue 2 Pages I_925-I_930
As a countermeasure against tsunami and storm surge, a novel breakwater, called as self-elevating seawall, has been started to construct in Japan. In this study, we investigated the viability of power generation using water-level difference generated before and after this type of seawall. 1/10-scale circulation flow experiments were conducted to measure the flow through the gate gap, and the inflow rate at a real size harbor was estimated. The power generation output is related to various parameters such as tidal pattern, tidal amplitude, local velocity, harbor area, depth, closure time, propeller diameter, and power generation efficiency. We estimated the potential power generation for 12 test cases for two hypothetical ports with different harbor areas. Although it will be hard to reach the commercial level of power generation, the system could be used as a promising niche energy source for local consumption, such as supplying electricity for aquaculture facility, seawater pumps, charging electric boats, and fishing gear. The system could also generate enough power to close the self-elevating seawall itself even in the event of a power outage. Although there are many issues to be solved for the realization of this power generation system, such as the reliability, efficiency, and profitability of the whole system, we will continue our research for the new synergy function of "disaster prevention × renewable energy".
