scholarly journals The Tidal Stream Energy Resource of the Fromveur Strait—A Review

2020 ◽  
Vol 8 (12) ◽  
pp. 1037
Author(s):  
Nicolas Guillou ◽  
Jean-Frédéric Charpentier ◽  
Mohamed Benbouzid

Refined assessments of the available tidal stream energy resource are required to optimize turbines design and guarantee successful implementations and operations of devices in the marine environment. Investigations primary focused on identifying areas with maximum current speeds. However, further information may be reached by exhibiting (i) resource temporal variability, (ii) superimposed effects of meteo-oceanographic conditions (including especially wind-generated surface-gravity waves), and (iii) potential environmental impacts of operating turbines at the regional (e.g., changes in sediment transport and surrounding seabed features, effects on marine water quality, etc.) and local (wake-wake interactions and energy output) scales. These aspects are here investigated by reviewing a series of research studies dedicated to the Fromveur Strait off western Brittany, a region with strong potential for tidal array development along the coast of France. Particular attention is dedicated to the exploitation of combined in-situ and remote-sensing observations and numerical simulations. Beyond a site specific characterization of the tidal stream energy resource, this review promotes a series of original approaches and analysis methods for turbines optimization, thus complementing technical specifications to secure the key steps of a tidal energy project and promote the growth of a reliable tidal stream energy exploitation.

Author(s):  
Nicolas Guillou ◽  
Simon P. Neill ◽  
Jérôme Thiébot

Initial selection of tidal stream energy sites is primarily based on identifying areas with the maximum current speeds. However, optimal design and deployment of turbines requires detailed investigations of the temporal variability of the available resource, focusing on areas with reduced variability, and hence the potential for more continuous energy supply. These aspects are investigated here for some of the most promising sites for tidal array development across the north-western European shelf seas: the Alderney Race, the Fromveur Strait, the Pentland Firth and the channels of Orkney. Particular attention was dedicated to asymmetry between the flood and ebb phases of the tidal cycle (due to the phase relationship between M 2 and M 4 constituents), and spring-neap variability of the available resource (due to M 2 and S 2 compound tides). A series of high-resolution models were exploited to (i) produce a detailed harmonic database of these three components, and (ii) characterize, using energy resource metrics, temporal variability of the available power density. There was a clear contrast between the Alderney Race, with reduced temporal variability over semi-diurnal and fortnightly time scales, and sites in western Brittany and North Scotland which, due to increased variability, appeared less attractive for optimal energy conversion. This article is part of the theme issue ‘New insights on tidal dynamics and tidal energy harvesting in the Alderney Race’.


2020 ◽  
Vol 8 (6) ◽  
pp. 411
Author(s):  
Zhaoqing Yang ◽  
Taiping Wang ◽  
Ziyu Xiao ◽  
Levi Kilcher ◽  
Kevin Haas ◽  
...  

Numerical models have been widely used for the resource characterization and assessment of tidal instream energy. The accurate assessment of tidal stream energy resources at a feasibility or project-design scale requires detailed hydrodynamic model simulations or high-quality field measurements. This study applied a three-dimensional finite-volume community ocean model (FVCOM) to simulate the tidal hydrodynamics in the Passamaquoddy–Cobscook Bay archipelago, with a focus on the Western Passage, to assist tidal energy resource assessment. IEC Technical specifications were considered in the model configurations and simulations. The model was calibrated and validated with field measurements. Energy fluxes and power densities along selected cross sections were calculated to evaluate the feasibility of the tidal energy development at several hotspots that feature strong currents. When taking both the high current speed and water depth into account, the model results showed that the Western Passage has great potential for the deployment of tidal energy farms. The maximum extractable power in the Western Passage was estimated using the Garrett and Cummins method. Different criteria and methods recommended by the IEC for resource characterization were evaluated and discussed using a sensitivity analysis of energy extraction for a hypothetical tidal turbine farm in the Western Passage.


Author(s):  
Angela Vazquez ◽  
Gregorio Iglesias

Potential areas for tidal stream energy development are conventionally selected on the basis of resource assessments. For all the importance of the resource, there are other elements (technological, economic, spatial, etc.) that must be taken into account in this selection. The objective of the present work is to develop a new methodology to select tidal stream hotspots accounting for all these relevant elements, and to apply it to a case study, showing in the process how the potential for tidal energy development can be fundamentally altered by technological, economic and spatial constraints. The case study is conducted in the Bristol Channel and Severn Estuary (UK), one of the regions with the largest tidal resource in the world. First, the most energetic areas are identified by means of a hydrodynamics model, calibrated and validated with field data. Second, the method calculates the energy that can be harnessed in these areas by means of a geospatial Matlab-based program designed ad hoc, and on the basis of the power curve and dimensions of a specific tidal turbine. Third, the spatial distribution of the levelised cost of energy (LCOE) is calculated, and a number of locations are selected as potential tidal sites. The fourth element in the approach is the consideration of restrictions due to overlap with other marine uses, such as shipping. As a result, potential conflict-free areas for tidal stream energy exploitation at an economical cost are identified. Thus, the case study illustrates this holistic approach to selecting tidal stream sites and the importance of elements other than the resource, which – for all its relevance – is shown to not guarantee by itself the potential for tidal stream energy development.


2015 ◽  
Vol 75 ◽  
pp. 626-639 ◽  
Author(s):  
M. Reza Hashemi ◽  
Simon P. Neill ◽  
Peter E. Robins ◽  
Alan G. Davies ◽  
Matt J. Lewis

Ocean Science ◽  
2020 ◽  
Vol 16 (6) ◽  
pp. 1337-1345
Author(s):  
J. A. Mattias Green ◽  
David T. Pugh

Abstract. Bardsey Island is located at the western end of the Llŷn Peninsula in northwestern Wales. Separated from the mainland by a channel that is some 3 km wide, it is surrounded by reversing tidal streams of up to 4 m s−1 during spring tides. These local hydrodynamic details and their consequences are unresolved by satellite altimetry and are not represented in regional tidal models. Here we look at the effects of the island on the strong tidal stream in terms of the budgets for tidal energy dissipation and the formation and shedding of eddies. We show, using local observations and a satellite-altimetry-constrained product (TPXO9), that the island has a large impact on the tidal stream and that even in this latest altimetry-constrained product the derived tidal stream is under-represented due to the island not being resolved. The effect of the island leads to an underestimate of the current speed in the TPXO9 data in the channel of up to a factor of 2.5, depending on the timing in the spring–neap cycle, and the average tidal energy resource is underestimated by a factor up to 14. The observed tidal amplitudes are higher at the mainland than at the island, and there is a detectable phase lag in the tide across the island; this effect is not seen in the TPXO9 data. The underestimate of the tide in the TPXO9 data has consequences for tidal dissipation and wake effect computation and shows that local observations are key to correctly estimating tidal energetics around small-scale coastal topography.


2020 ◽  
Vol 8 (9) ◽  
pp. 705 ◽  
Author(s):  
Nicolas Guillou ◽  
George Lavidas ◽  
Georges Chapalain

Over recent decades, the exploitation of wave energy resources has sparked a wide range of technologies dedicated to capturing the available power with maximum efficiency, reduced costs, and minimum environmental impacts. These different objectives are fundamental to guarantee the development of the marine wave energy sector, but require also refined assessments of available resource and expected generated power to optimize devices designs and locations. We reviewed here the most recent resource characterizations starting from (i) investigations based on available observations (in situ and satellite) and hindcast databases to (ii) refined numerical simulations specifically dedicated to wave power assessments. After an overall description of formulations and energy metrics adopted in resource characterization, we exhibited the benefits, limitations and potential of the different methods discussing results obtained in the most energetic locations around the world. Particular attention was dedicated to uncertainties in the assessment of the available and expected powers associated with wave–climate temporal variability, physical processes (such as wave–current interactions), model implementation and energy extraction. This up-to-date review provided original methods complementing the standard technical specifications liable to feed advanced wave energy resource assessment.


2016 ◽  
Vol 180 ◽  
pp. 402-415 ◽  
Author(s):  
Nicolas Guillou ◽  
Georges Chapalain ◽  
Simon P. Neill

2020 ◽  
Author(s):  
Matt Lewis ◽  
John Maskell ◽  
Daniel Coles ◽  
Michael Ridgill ◽  
Simon Neill

<p>Tidal-stream energy research has often focused on the applicability of the resource to large electricity distribution networks, or reducing costs so it can compete with other renewables (such as offshore wind). Here we explore how tidal electricity may be worth the additional cost, as the quality and predictability of the electricity could be advantageous – especially to remote “off-grid” communities and industry.</p><p>The regular motion from astronomical forces allows the tide to be predicted far into the future, and therefore idealised scenarios of phasing tidal electricity supply to demand can be explored. A normalised tidal-stream turbine power curve, developed from published data on 15 devices, was developed. Tidal harmonics of a region, based on ocean model output, were used in conjunction with this normalised tidal-stream power curve, and predictions of yield and the timing of electricity supply were made. Such analysis allows the type and number of turbines needed for a specific community requirement, as well as a resource-led tidal turbine optimisation for a region. For example, with a simple M2 tide (12.42hour period) of 2m/s peak flow, which represents mean flow conditions, a rated turbine speed of 1.8m/s gives the highest yield-density of all likely turbine configurations (i.e. calculated from power density and so ignores turbine diameter), and with a 41% Capacity Factor. Furthermore, as tidal current and power predictions can be made, we explore the battery size needed for a given electricity demand timeseries (e.g. baseload, or offshore aquaculture). Our analysis finds tidal-stream energy could be much more useful than other forms of renewable energy to off-grid communities due to the predictability and persistence of the electricity supply. Moreover, our standardised power curve method will facilitate technical tidal energy resource assessment for any region.</p>


Sign in / Sign up

Export Citation Format

Share Document