1. Flow Characteristics and Energy Potential in Tsugaru Strait toward Tide and Sea Current Power Generation by Makoto MIYATAKE Institute of National Colleges of Technology, Hakodate National College of Technology Department of Civil Engineering, Hakodate National College of Technology

2. Backgrounds Basic message Previous Qualitative Knowledge The seasonal water flow characteristics are one of important factors that need to consider for power generation in Tsugaru Strait. The seasonal characteristics of water flow across Tsugaru Strait has been known, that is dominated by both tide and ocean current. The interaction mechanism in-depth of tide and ocean current in four seasons has not been well understood. View of Tsugaru Strait during Winter Storm Season OpenHydro and EDF (France): 16m diameter ×4 2MW each 35 m water depth electricity for 4000 homes

3. To clarify the current interaction mechanism relationship between tide and ocean current by using the numerical modeling after reproducing the observation results accurately. Objectives To investigate the variation characteristics of tide and ocean current through field observations of four seasons. To estimate the energy potential based on the results of both field observations and numerical simulations.

4. Field Observations Setup Transmission Frequency 300kHz Maximum Setup Depth 260m Maximum Thickness of Layer 0.2m~ 16.0m Maximum Number of Layer 128 contentsspec Specifications of ADCP Observation Periods Spring18 th /3/2013~18 th /4/2013(31days) Summer31 st /7/2013~4 th /9/2013(35days) Autumn19 th /10/2013~4 th /12/2013(45days) Winter4 th /12/2013~20 th /1/2014(47days) Observation Layers Upper23.3m from sea bottom Middle12.2m from sea bottom Bottom3.2m from sea bottom Observation Time Intervals 60min.(Obs. Duration 40min., Sampling 1s.) Observation Site and Method

5. Relationship Between Multi-layer Velocity and Tide (Spring) Velocity(cm/s) Upper Layer Middle Layer Bottom Layer Observation Dutation

6. Normalized Cross-Correlation Function Upper Layer Middle Layer Bottom Layer Normalized Cross- Correlation Function Velocity(m/s) Time Lag(hr) Tide Difference(cm) (a) Relationship between Cross- Correlation and Time Lag (b) Correlation of Tide Difference and Flow Velocity including 3hr Lags Upper Middle Bottom

7. Normalized Cross-Correlation Function Frequency(Hz) Power Spectrum(cm 2 sec)

8. Tidal Current Ellipses of Principal Four Tidal Components

9. Water Depth [m] Longitude [deg] Latitude [deg] 50m 100m 300m 200m Computation Range E140 - E141.383, N41.183 - N41.833 Mesh Scale （  lon. x  lat. ） 30sec x 30sec Mesh Scale （ Vertical ） 1.0m--15.0m Time Step10sec Bottom FrictionSlip-Boundary Condition Start Time15 th /March 2013 00:00 (UTC) Case #123 Tidal Current Tidal Current Velocity as Inflow Boundary Condition Given from TPXO7.2. ― Ocean Current ― Ocean Current Velocity as Inflow Boundary Condition Given from JAMSTEC FRA-JCOPE2 Numerical Simulations for Water Current Specifications of Calculation Computation Area Computation Cases MITgcm(MIT General Circulation Model ) Same as Spring Obs.

10. Comparison Numerical Result with Observation Data

11. Orbit Radius [m/s] Longitude [deg] Latitude [deg] O1 1m/s Orbit Radius [m/s] Longitude [deg] Latitude [deg] K1 1m/s Orbit Radius [m/s] Longitude [deg] Latitude [deg] M2 1m/s Orbit Radius [m/s] Longitude [deg] Latitude [deg] S2 1m/s Black color ： anticlockwise ， Pink Color ： clockwise Tidal Current Ellipse Distribution(Case 1; tidal current only )

12. Orbit Radius [m/s] Longitude [deg] Latitude [deg] O1 1m/s Orbit Radius [m/s] Longitude [deg] Latitude [deg] K1 1m/s Orbit Radius [m/s] Longitude [deg] Latitude [deg] M2 1m/s Orbit Radius [m/s] Longitude [deg] Latitude [deg] S2 1m/s Tidal Ellipse Current Distribution(Case 2; tidal+ocean current ) Black color ： anticlockwise ， Pink Color ： clockwise

13. residual current velocity [m/s] Longitude [deg] Latitude [deg] 1m/s residual current velocity [m/s] Longitude [deg] 1m/s Case 1 Case 3 residual current velocity [m/s] Longitude [deg] Latitude [deg] 1m/s Case 2 Latitude [deg] Residual Current Velocity Distribution Case1 ： tidal current only Case2 ： tidal+ocean current Case3 ： ocean current only

14. Density of Energy [kW/m 2 ] Longitude [deg] Latitude [deg] Density of Energy [kW/m 2 ] Longitude [deg] Latitude [deg] Density of Energy [kW/m 2 ] Longitude [deg] Latitude [deg] Density of Energy [kW/m 2 ] Longitude [deg] Latitude [deg] Case 1 Case 2 Depth Averaged Energy Potential Distribution Duration average Duration maximum Duration average Duration maximum

15. Brief Summaries The SE water flow accompanied by periodic variations is constructed by combining the southeastward residual current with tidal current in direction of NW-SE. The next step in this work are as follows. The energy potential distribution estimated from the analysis results indicates that the most appropriate location of power generation is around the side of Shimokita Peninsula coast waters. To verify the observation data in other seasons and clarify the seasonal variation of water current and the energy potential through the numerical simulation.