Natural Currents Energy Services, LLC
Potential Tidal Power for New Jersey 2010-15 Sponsored by NJDOT and UTRC Report 140-03
ADP Measurements of Spatial Tidal Flow in the Shrewsbury River near Sandy Hook, NJ
Roger Bason Christina J. Hartwell Roman Keniuk February 10, 2011 Contact Information: 845-691-4008 (O), rbason@naturalcurrents.com
Introduction This report presents a summary of site investigation findings based on fieldwork completed during May 2010 on the Shrewsbury River near Sandy Hook, New Jersey. On-site activities included site specific surveys consisting of three (3) tracks of data measuring tidal speeds through the water column to the seabed in 1m cells or increments. Data for tidal current speeds was acquired using Sontek Acoustic Doppler Profiler (ADP) technology1. The field investigation also included a review of area charts provided by the clients, observations of tide changes, digital photography and video of the site and assessment activities.
Time and date stamped field data was collected on May 20 and 21, 2010 over a 4 km area parallel and immediately offshore from the Highlands, New Jersey shoreline. The site survey was completed by a Natural Currents field team consisting of Roger Bason, Christina J. Hartwell, Roman Keniuk. Dr. Hansong Tang participated in field data collection and site observations on May 21, 2010. Based on field observations, a review of charts and tide tables for the region, Natural Currents provides this spatial analysis of tidal flows to assist in coordination of results with high resolution computer modeling of tidal flows along New Jersey coastlines 2 (Tang, et al).
A special focus of data collection was at a probable tidal turbine deployment property just south of the Sandy Hook Bridge (Route 36) on the west shoreline of the Shrewsbury River. This report includes a site description and a summary methods and equipment for tidal current flow measurement. It also provides a review of ADP output graphical mapping of data for the probable tidal deployment site south of the Sandy Hook Bridge and a summary of findings. The results of this investigation indicate that locating known tidal turbine technology for electrical power generation at this location is highly feasible.
Additional excel (.xls) documents are presented that provide a summary of Sontek ADP data files3. These include: profile number, time, distance, GPS latitude, GPS longitude, depth, ucurrent flow speed in m/sec and other related data that tracks data quality and water discharge information.
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Project Background Natural Currents is a leading US technology company producing revolutionary energy systems for emerging renewable energy (RE) markets, with a primary focus on ocean tidal power generation. The proprietary Red Hawk and Sea Dragon Tidal Turbines produce electricity by harnessing the free-flowing movement of the tides in coastal and shoreline areas. Project goals and Natural Currents technology and business plan support the critical goals of both the NJ Energy Master Plan (NJ EMP) and the Global Warming Response Act (GWRA) for NJ to generate 20% or more of its energy needs from renewable sources by 2020.
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Site Description The site location is indicated as the red rectangle in the aerial photo below. Located in the Borough of Highlands, New Jersey on the west shore of the Shrewsbury River, it is characterized by strong tidal currents on both the ebb and flood cycles.
Figure 1: Site Location
Figure 2: Subject Property data collection
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The site itself is a group of primarily residential structures located on the west shore of the Shrewsbury River, just south of the Rt. 36 Bridge crossing in Highlands, NJ. The site has some existing
docks and bulkheads. Riparian grants extend up to 70 feet in the Shrewsbury River from the shoreline.
The existing dock and pier structures will be adapted to provide optimal placement of Natural Currents Tidal electric turbines. Work is in progress to determine the best suited array and places of turbines in the location.
Figure 3: Possible locations for the turbine installation
3.3 Tidal Power Potential/Technical Analysis Accurate measurements were made of tidal flow on May 20 and May 21, 2010. These include evaluations of the water profile in the surrounding waters of the subject property. The following photos portray the set up of the ADCP (Acoustic Doppler Current Profiler) and data collection.
ADCP setup is comprised of Sontek River Surveyor ADCP with a Low Profile ADP processor that supports RS232 serial communication between the sensor and the processor. The ADP sensor consists of a 500 kHz transducer with accuracy to 25m in depth for bottom track and
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single scan bathymetric analysis. Data acquisition is completed using a Dell Mini Laptop with a Microsoft Windows XP platform.
Figure 4. NC Staff making field measurements
Figure 5. Keniuk checks Sontek ADP
Figures 4 & 5 display the equipment in the process of collecting real-time data
Water Velocity Measurements are taken and Real time GPS (Global Positioning System) Field Monitoring is logged to enable accurate lat /long positioning and post processing of field data. Water depth and water current speed data are then plotted using Google Earth to portray the field data collection points and summary information on aerial photos of the site.
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Figure 6. Field Survey Boat Track (Red)
Figure 7: Onsite ADP Profile of collected data track
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Figure 8: ADP current profile over time ADCP transect showing desirable velocities of 2-3 m/s in oranges & reds.
Six data fields are presented in the Sontek data display presented above. These include the following fields starting from the top left and moving clockwise: 1. Vector representations of the depth averaged water speed velocity and direction. 2. Numerical data display of output parameters. 3. X, Y, Z axis that indicates direction and average of water speed measurements. 4. A color scale indicating water speeds. The hotter the color, the faster the water. 5. Bottom Left: water speed measured at depth, presented in nine separate ‘bins’ of depth (surface to seabed) 6. A linear summary of ‘hot spots’ (orange) of water speed. Localized current profiles are studied in order to determine optimal turbine placement within the water profile. The following figure represents data analyzed from one specific profile:
ADP Data: Subject Properties Highlands, NJ May 21st, 2010 file name: ADP Data File: OB1005211059.adp Data analyzed using Profile # 556 from SonTek ViewADP
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Figure 10: Water speed with depth at a specific profile
Figure 11: Location of Profile #556
Summary Spatial tidal data collection findings to provide interface with High-Resolution Tidal Flow Computer Modeling are presented below. All tidal data collected are time and location specific due to the constant change in tidal flux at any given location. Therefore Tidal Monitoring stations are referenced in this table, in this case a monitoring location at Sandy Hook, NJ. Due to the distance of the location from the center of our data collection tracks, the time difference between the Station and our collection is presented.
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Table 1. Summary ADP Field Data: Shrewsbury River, NJ1
Number
ADP Track/File
Water Way
ADP Date & Time
Nearest Tidal Station 2
High Tide at Nearest Tidal Station3 14:02
Height Feet (meters)
High Tide Slack at Highlands (+30 min)
# of Profiles Sontek ADP 4
#1
OB1005201124
Shrewsbury River, NJ
40˚28’N, 74˚0.6’W
#2
OB1005201210
Shrewsbury River, NJ
#3
OB1005211059
Shrewsbury River, NJ
May 20, 2010 at 23:24 May 20, 2010 at 24:10 May 21, 2010 at 22:59
4.9 ft (1.49m)
14:32
257
40˚28’N, 74˚0.6’W
14:02
5.2 ft (1.55m)
14:32
497
40˚28’N, 74˚0.6’W
15:00
4.9 ft (1.49m)
15:30
780
These data are presented in accompanying .xls files described in Column 2 in the Table – ADP Track and File Name. The waterway, time and date of data collection (Column 3, Column 4) is presented to enable these data to be correlated to the state of tidal flux based on the nearest tidal station (Column 6) which is at Sandy Hook, NJ. 4
High Tide for the Sandy Hook station is presented in Column 6, with the height of the tide provided in Column 7 in feet and meters. The time differential is presented in Column 8 that explaining data collection location tidal flux is 30 minutes later than tide information presented at the Sandy Hook Station. When the detailed data is reviewed for each of the Sontek Tracks (Column 2) the number of data profiles is indicated in Column 9.
A clear understanding of the tidal flux conditions results from a detailed review of the ADP files referenced above, correlating these data with GPS latitude and longitude coordinates and then comparing the data with changing tidal conditions available from Eldridge Tidal Tables for the site and date specific conditions.
1
Times are based on Daylight Savings Time 2010 High & Low Water Sandy Hook, NJ p. 136 3 White, Robert Elgridge, Jr. Eldridge Tide & Pilot Book 2010. Medfield, MA. 2009. 4 Sontek / YSI. Riversurveyor System Manual. Software Version 4.10. February 1, 2004. 2
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Recommendations for Tidal System Installation Based on a review of all available research and field data collected, the site would appear to have sufficient depth, water speed and space to install either a single 150 kW Sea Dragon turbine or a series of these systems on the subject properties.
Deployment of turbines will be developed to fit the needs of the Highlands Deployment Site-01 and could include a mobile barge or dock fixed structure. The tidal array may also include fixed turbine(s) on new dock construction off of the existing property to utilize the property owner’s riparian land grants.
1. Based on discussions with the client and field observations, it would appear that the preferred location would be within the subject property Riparian Grants and Lease(s).
2. Based on these measurements and initial observations of the water depth, it would appear that the maximum power output of the available locations at this site would be approximately 150 kW of peak power. A module consisting of two or three Sea Dragon Turbines providing ~300 – 450 kW of peak power generation is recommended.
3. The site appears to be able to accommodate up to three turbines (peak 450 kW output), each of which has approximately the dimension of a broad cylinder that measures fifteen (15) meters across and (5) feet in depth or 1.6m.
4. Based on our present understanding of the utility bills, it would appear that the installation of two or three turbines would offset approximately all present electrical load and enable sale of excess power to the grid.
5. Project installation, along with maintenance tasks such as periodic system inspections, turbine cleaning and system monitoring hold potential to create green jobs for the local economy as well as power production that generates no pollution and requires no fuel.
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5. Site Maps
USGS Site Map
NOAA Site Map
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1
Sontek / YSI Acoustic Doppler Profiler, 1500 kHz unit with maximum profiling range of 25m, a resolution of 0.25-1.0m, blanking distance of 0.4m and minimum depth of 0.9m. 2
Tang, Hansong, W. Cheng, S. Kraatz. Coarse Mesh Estimate and Fine Mesh for HighResolution of Tidal Energy along NJ Coastlines. Dept of Civil Engineering. CUNY. January 8, 2011. 3
Sontek / YSI. River Surveyor System Manual. Software Version 4.10. February 1, 2004.
4
White, Robert Eldridge, Jr. Eldridge Tide and Pilot Book 2010. Medfield, MA. 2009.
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