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Title: Tidal energy extraction modifies tidal asymmetry and transport in a shallow, well-mixed estuary

Journal Article · · Frontiers in Marine Science
 [1]; ORCiD logo [2];  [1];  [1]
  1. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
  2. Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Univ. of Washington, Seattle, WA (United States)

Tidal energy extraction is increasingly being studied as a potential renewable energy resource in estuaries worldwide. Although it is understood that energy extraction via tidal stream turbines can modify currents and transport within estuaries, it is not clear how the underlying nonlinear physical mechanisms dictating tidal hydrodynamics are modulated. This research investigates the influence of a hypothetical tidal stream turbine array on barotropic tidal processes in a shallow, well-mixed system: the Piscataqua River – Great Bay (PRGB) estuary, using a numerical model. The modeled turbine farm includes 180 turbines which would extract an estimated 44.7 GWh of energy, annually. The tidal hydrodynamic model for the existing condition is validated with in-situ observations of currents and water level before analyzing tidal asymmetry and transport with and without tidal turbines. Results indicate that the tidal turbine array will decrease tidal elevation and current magnitudes system-wide, but generally reduce ebb currents and transport more than flood over most of the estuary footprint, thereby diminishing tidal asymmetry. The smaller asymmetric distortion compared to the no-turbine case is attributed to reductions in the storage volume of water over the estuary’s extensive tidal flat regions between low and high waters which decreases the associated nonlinear intertidal storage mechanism up to 25%. This leads to weakened ebb dominance over estuary sections from the mouth to mid-reaches, where depths are deep enough to keep the combined nonlinear shallow water and frictional effects from asserting control over the storage mechanism. Even in upstream shallow regions where depth-dependent friction controls asymmetry in both cases, the frictional mechanism is reduced only by 10% with turbines. Some environmental considerations of this work are discussed, with focus on sediment transport, water quality, and ecology.

Research Organization:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Water Power Technologies Office
Grant/Contract Number:
AC05-76RL01830
OSTI ID:
2305509
Report Number(s):
PNNL-SA-186613
Journal Information:
Frontiers in Marine Science, Vol. 10; ISSN 2296-7745
Publisher:
Frontiers Research FoundationCopyright Statement
Country of Publication:
United States
Language:
English

References (56)

On basin hyposmetry and the morphodynamic response of coastal inlet systems journal March 1981
True Colors of Oceanography: Guidelines for Effective and Accurate Colormap Selection journal September 2016
Changing Tides: The Role of Natural and Anthropogenic Factors journal January 2020
Simulation of Estuarine Flooding and Dewatering with Application to Great Bay, New Hampshire journal August 1998
Impact of different operating modes for a Severn Barrage on the tidal power and flood inundation in the Severn Estuary, UK journal July 2010
A note on tidal asymmetry in the severn estuary journal October 1981
A comparison of numerical and analytical predictions of the tidal stream power resource of Massachusetts, USA journal December 2017
Capital costs in tidal stream energy projects – A spatial approach journal July 2016
Spatio-temporal variability of tidal asymmetry due to multiple coastal constructions along the west coast of Korea journal December 2014
Multi-scale ocean response to a large tidal stream turbine array journal December 2017
A study of non-linear tidal propagation in shallow inlet/estuarine systems Part II: Theory journal August 1985
Flood/ebb tidal asymmetry in a shallow sandy estuary and the impact on net sand transport journal January 2010
A Study of Tidal Energy Dissipation and Bottom Stress in an Estuary journal November 1980
Modeling the Effects of Tidal Energy Extraction on Estuarine Hydrodynamics in a Stratified Estuary journal August 2013
Tidal and subtidal transport in short, tidally-driven estuaries with low rates of freshwater input journal July 2021
Biogeochemical Processes in Estuaries book January 2003
A modelling study of the tidal stream resource of the Pentland Firth, Scotland journal March 2017
Modeling nonlinear tidal evolution in an energetic estuary journal April 2019
The impact of tidal stream turbines on large-scale sediment dynamics journal December 2009
Tides, sea-level rise and tidal power extraction on the European shelf journal June 2012
Far-field effects of tidal energy extraction in the Minas Passage on tidal circulation in the Bay of Fundy and Gulf of Maine using a nested-grid coastal circulation model journal August 2011
A modeling study of tidal energy extraction and the associated impact on tidal circulation in a multi-inlet bay system of Puget Sound journal December 2017
Numerical modeling of tides in the Great Bay Estuarine System: dynamical balance and spring–neap residual modulation journal May 2003
The power potential of tidal currents in channels journal June 2005
Modeling the tidal channel morphodynamics in a macro-tidal embayment, Hangzhou Bay, China journal August 2009
Accelerating loss of seagrasses across the globe threatens coastal ecosystems journal July 2009
Review on configuration and control methods of tidal current turbines journal July 2019
A review of tidal energy—Resource, feedbacks, and environmental interactions journal November 2021
Preliminary assessment of a tidal test site on the Minho estuary journal October 2020
Distribution of bottom stress and tidal energy dissipation in a well-mixed estuary journal September 1983
Sediment pumping by tidal asymmetry in a partially mixed estuary journal July 2007
Device interactions in reducing the cost of tidal stream energy journal June 2015
Tidal stream energy resource characterization in the Salish Sea journal July 2021
An Unstructured Grid, Finite-Volume, Three-Dimensional, Primitive Equations Ocean Model: Application to Coastal Ocean and Estuaries journal January 2003
An ecosystem services assessment using bioextraction technologies for removal of nitrogen and other substances in Long Island Sound and the Great Bay/Piscataqua Region Estuaries text January 2015
Temporal Variability in Salinity, Temperature and Suspended Sediments in a Gulf of Maine Estuary (Great Bay Estuary, New Hampshire) book January 2005
Optimization of the hydrodynamic performance of a vertical Axis tidal (VAT) turbine using CFD-Taguchi approach journal October 2020
Determining tidal turbine farm efficiency in the Western Passage using the disc actuator theory journal December 2015
A Modeling Study of the Potential Water Quality Impacts from In-Stream Tidal Energy Extraction journal November 2013
Bioextractive Removal of Nitrogen by Oysters in Great Bay Piscataqua River Estuary, New Hampshire, USA journal November 2019
Simulation of the Great Bay Estuarine System: Tides with tidal flats wetting and drying journal May 2002
Modeling of in-stream tidal energy development and its potential effects in Tacoma Narrows, Washington, USA journal October 2014
Tidal stream energy impact on the transient and residual flow in an estuary: A 3D analysis journal March 2014
Observed fluxes of water, salt and suspended sediment in a partly mixed estuary journal February 1985
The influence of tidal forcing on groundwater flow and nutrient exchange in a salt marsh-dominated estuary journal January 2011
Land reclamation and its impact on tidal dynamics in Jiaozhou Bay, Qingdao, China journal December 2014
Modelling tidal stream turbines in a three-dimensional wave-current fully coupled oceanographic model journal December 2017
Tidal asymmetry and estuarine morphology journal August 1986
Modeling bed-load transport of coarse sediments in the Great Bay Estuary, New Hampshire journal December 2003
Sediment Trapping in Estuaries journal January 2018
The Generation of Overtides in Flow Around a Headland in a Low Inflow Estuary journal February 2019
Field and laboratory observations of bed stress and associated nutrient release in a tidal estuary journal August 2015
Modelling the hydrodynamic and morphological impacts of a tidal stream development in Ramsey Sound journal October 2018
Lateral variability of subtidal flow at the mid‐reaches of a macrotidal estuary journal September 2017
Modeling tidal stream energy extraction and its effects on transport processes in a tidal channel and bay system using a three-dimensional coastal ocean model journal February 2013
Non-linear tidal distortion in shallow well-mixed estuaries: a synthesis journal November 1988