Tidal Power Development Research Articles

Estimating Effects of Tidal Power Projects and Climate Change on Threatened and Endangered Marine Species and Their Food Web

Marine hydrokinetic power projects will operate as marine environments change in response to increased atmospheric carbon dioxide concentrations. We considered how tidal power development and stressors resulting from climate change may affect Puget Sound species listed under the U.S. Endangered Species Act (ESA) and their food web. We used risk tables to assess the singular and combined effects of tidal power development and climate change. Tidal power development and climate change posed risks to ESA-listed species, and risk increased with incorporation of the effects of these stressors on predators and prey of ESA-listed species. In contrast, results of a model of strikes on ESA-listed species from turbine blades suggested that few ESA-listed species are likely to be killed by a commercial-scale tidal turbine array. We applied scenarios to a food web model of Puget Sound to explore the effects of tidal power and climate change on ESA-listed species using more quantitative analytical techniques. To simulate development of tidal power, we applied results of the blade strike model. To simulate environmental changes over the next 50 years, we applied scenarios of change in primary production, plankton community structure, dissolved oxygen, ocean acidification, and freshwater flooding events. No effects of tidal power development on ESA-listed species were detected from the food web model output, but the effects of climate change on them and other members of the food web were large. Our analyses exemplify how natural resource managers might assess environmental effects of marine technologies in ways that explicitly incorporate climate change and consider multiple ESA-listed species in the context of their ecological community. Estimación de los Efectos de Proyectos de Energía de las Mareas y el Cambio Climático sobre Especies Marinas Amenazadas y en Peligro y su Red Alimentaria.

Distribution of subtidal sedimentary bedforms in a macrotidal setting: The Bay of Fundy, Atlantic Canada

The Bay of Fundy, Canada, a large macrotidal embayment with the World's highest recorded tides, was mapped using multibeam sonar systems. High-resolution imagery of seafloor terrain and backscatter strength, combined with geophysical and sampling data, reveal for the first time the morphology, architecture, and spatial relationships of a spectrum of bedforms: (1) flow-transverse bedforms occur as both discrete large two-dimensional dunes and as three-dimensional dunes in sand sheets; (2) flow-parallel bedforms are numerous straight ridges described by others as horse mussel bioherms; (3) sets of banner banks that flank prominent headlands and major shoals. The suite of bedforms developed during the Holocene, as tidal energy increased due to the bay approaching resonance. We consider the evolution of these bedforms, their migration potential and how they may place limitations on future in-stream tidal power development in the Bay of Fundy.

Tidal Power Development in Maine: Stakeholder Identification and Perceptions of Engagement

Development of renewable energy affects or is affected by numerous stakeholders. Understanding who the stakeholders are and how they are engaged in the process is necessary for improving the responsible development of renewable energy technologies. Using structured community interviews and in-depth ethnographic research (semi-structured interviews, informal interviews, observations, and document review), we identified and characterized the most salient stakeholders associated with tidal power development in Maine and documented stakeholder perceptions of developer engagement strategies. Stakeholder characterization was facilitated using a framework by Mitchell et al. (The Academy of Management Review 22:853–886, 1997) that characterizes salient stakeholders using attributes of power, urgency, and legitimacy. Key stakeholders identified include fishermen, community members, tribes, regulators, developers, and scientists. Fishermen and regulators are definitive stakeholders, with legitimacy, power, and urgency in the process. Tribes are considered dominant stakeholders; they have legitimacy and power, but their interests are, at this time, not viewed as urgent. Scientists are considered to have urgency and power. The developers viewed their stakeholder engagement strategy as open and transparent. Community stakeholders, regulators, and fishermen generally perceived the developer's approach as effective; they noted the company's accessibility and their efforts to engage stakeholders early and often. Given the dynamic nature of stakeholder salience, our findings highlight the importance of engaging dominant stakeholders so that future conflict can be more easily avoided as new information develops. Our approach can be used to inform stakeholder identification and engagement research in other renewable energy contexts.

HYDRODYNAMIC IMPACTS OF TIDAL POWER LAGOONS IN THE BAY OF FUNDY

It has long been identified that the Bay of Fundy, Canada, is one of the world's premier locations for the development of tidal power generating systems, since it has some of the world's largest tidal ranges. Several proposals have been made in recent years to find economical ways to harness the power of tides. There is presently considerable interest in installing tidal power lagoons in the Bay of Fundy. The lagoon concept involves temporarily storing seawater behind an impoundment dike and generating power by gradually releasing the impounded seawater through conventional low-head hydroelectric turbines. A tidal lagoon will inherently modify the tides and tidal currents regime in the vicinity of the lagoon, and possibly induce effects that may be felt throughout the entire bay. The nature of these hydrodynamic impacts will likely depend on the size of the tidal lagoon, its location, and its method of operation. Any changes in the tidal hydrodynamics caused by a tidal lagoon may upset ecosystems that are well adapted to existing conditions. The scale and character of the potential hydrodynamic impacts due to tidal lagoons operating in the Bay of Fundy have not been previously investigated. This paper presents the results of a hydrodynamic model developed to analyze, predict, and quantify the potential changes in the tidal hydrodynamics changes (water levels, tidal range, circulation patterns and tidal currents) due to the presence of a single tidal lagoon, or multiple lagoons, operating in the upper Bay of Fundy, Canada. The extent of the changes due to different scenarios involving several number, size and location of lagoons, as well as their operating mode is also investigated. The final purpose of this novel study is to assist with decisions concerning the development of the vast tidal energy resources available in the Bay of Fundy, Canada.

Influence of varying tidal prism on hydrodynamics and sedimentary processes in a hypertidal salt marsh creek

ABSTRACTRecent initiatives directing tidal power development in the Bay of Fundy have raised questions about far‐field environmental impacts related to energy extraction. It is understood that commercial scale tidal power installations in the Minas Passage will result in an overall decrease in tidal amplitude in the Minas Basin. Corresponding changes in sedimentation patterns may or may not be within the natural range of variability, and it is hypothesized that intertidal sedimentation rates will demonstrate a non‐linear response to modification of the tidal energy regime. This research considers acoustic Doppler velocimeter (ADV) and optical backscatter sensor (OBS) data from a sheltered tidal creek in the Minas Basin, for analysis of tidal characteristics in a hypertidal creek environment over spring and neap tidal cycles. Sediment deposition in the creek was also measured. Results show a first‐order control of topography on flow magnitude in the tidal creek, which impacts net sediment deposition through resuspension and removal of newly introduced material. This study demonstrates that tides which peak around the bankfull level show reduced early ebb stage turbulence and flow velocity and encourage an extended depositional period. The dynamics of marshfull tides may be responsible for the maximum sediment deposition in tidal creeks, providing large amounts of material that is eventually distributed to and deposited on marsh surfaces. Copyright © 2012 John Wiley & Sons, Ltd.

The dynamics of an energetic tidal channel, the Pentland Firth, Scotland

Shelf tidal stream velocities are accelerated by nearshore geographic features, such as headlands and islands. In the search for sustainable forms of electrical energy generation, such locations may become attractive for tidal stream power developments. For some prospective tidal stream energy sites, however, little is known about the intricacies of the local tidal dynamics: knowledge which is crucial to the understanding of the resource and the potential environmental consequences of its extraction.In this paper a two dimensional hydrodynamic model is used to investigate a complex tidal strait, the Pentland Firth (Scotland, UK). This channel, considered one of the most promising tidal stream energy sites in the world, is set for extensive development over the coming decade. We show that the tidal stream velocities that regularly occur within, and up to 20-km beyond the Pentland Firth, are accelerated above that of a free shallow-water wave. The primary mechanism for these accelerations is hydraulic in nature, associated with a large shift in tidal phase. Tidal streaming around headlands and islands further promotes conversion from potential to kinetic energy. We calculate a mean energy flux into the Pentland Firth from the North Atlantic Ocean of 8.97GW. Changes in tidal amplitude and phase along the strait are associated with a reduction in energy flux, such that the majority (∼60%) of the incoming energy is lost within the Pentland Firth through bed friction.Localised geographical factors complicate the tidal dynamics of the Pentland Firth, therefore detailed modelling is the only means with which to accurately characterise the environmental conditions in this channel. Of more general oceanographic significance, this example shows that high levels of tidal energy dissipation are associated with energetic tidal straits. Energy losses in these straits may contribute significantly to balancing the energy flux onto the continental shelf from the deep seas.

Stock Origin of Migratory Atlantic Sturgeon in Minas Basin, Inner Bay of Fundy, Canada, Determined by Microsatellite and Mitochondrial DNA Analyses

AbstractFive distinct population segments of Atlantic sturgeon Acipenser oxyrinchus were recently listed (April 2012) as endangered or threatened under the U.S. Endangered Species Act. Atlantic sturgeon are anadromous, spawning occurs in rivers from the St. Lawrence River, Quebec, to the Satilla River, Georgia, and subadults and adults undertake extensive coastal migrations. Bycatch of Atlantic sturgeon in coastal fisheries may have resulted in the slowed or failed rebuilding of many populations despite the imposition of a U.S. federal moratorium on their harvest in 1998. Canada's Bay of Fundy hosts weir and trawl fisheries which bycatch Atlantic sturgeon of unknown origin. Additionally, tidal power development projects for the Bay of Fundy have been proposed which could detrimentally impact migratory sturgeon. We hypothesized that the Atlantic sturgeon that occur in Minas Basin in the Bay of Fundy are of local Saint John River, New Brunswick, origin with little or no U.S. contribution. We used microsatellite DNA (11 loci) and mitochondrial DNA control region sequence analysis along with previously determined characterizations of nine reference spawning populations to quantify their stock origin. We determined that the summer assemblage of Atlantic sturgeon collected within Minas Basin was of mixed origin, with a greater than 60% contribution from the nearby Saint John River but with a substantial (34–36%) contribution from the Kennebec River, Maine, and a smaller (1–2%) contribution from the Hudson River, New York. There was significant genetic heterogeneity between smaller (<130 cm) and larger individuals (≥130 cm) in Minas Basin; however, the smaller specimens were not exclusively of proximal Saint John River origin. Our results indicate that Atlantic sturgeon of U.S. origin are vulnerable to anthropogenic impacts in the Bay of Fundy, particularly those of Kennebec River origin.

Research for the Sustainable Development of Tidal Power in Maine

Generating electricity from Maine’s substantial tides has been a dream for generations. Today, the state is poised for a new era in sustainable tidal-power development. A pilot project is already underway in the Cobscook Bay/Western Passage area near Eastport and Lubec. Tidal-power development presents technical, environmental, and social challenges, however, and the authors discuss how the Maine Tidal Power Initiative is working to develop a cooperative framework that integrates stakeholders, developers, and policymakers to tackle some of these challenges.

Macrotidal estuaries: a region of collision between migratory marine animals and tidal power development

Macrotidal estuaries of the inner Bay of Fundy are utilized by large numbers of migratory fishes, particularly dogfish, sturgeon, herring, shad, Atlantic salmon and striped bass as well as by other migratory marine animals, many of which have large body sizes (squid, Lamnid sharks, seals and whales). Tagging experiments indicate the fishes originate from stocks derived over the entire North American Atlantic coast from Florida to Labrador. Population estimates suggest up to 2.0 times 106adult American shad (Alosa sapidissima) migrate through an individual embayment each year. These migrations are an integral part of the life history of the respective species and appear to be controlled in part by the near shore movements of ocean currents. In other regions of the world similar macrotidal estuaries exist (Cook Inlet, Alaska; Severn Estuary, U.K.) and they, like the Bay of Fundy, are linked in continuum to the local ocean currents. We propose that marine animals utilize all these regions in a manner similar to the Bay of Fundy estuaries and properly designed surveys will reveal their presence. Fish passage studies utilizing the Annapolis estuary low-head, tidal turbine on the Bay of Fundy have shown that turbine related mortality of 20–80% per passage occurs depending on fish species, fish size and the efficiency of turbine operation. We suggest that introduction of tidal turbines into open ocean current systems will cause widespread impact on marine populations resulting in significant declines in abundance.

Macrotidal estuaries: a region of collision between migratory marine animals and tidal power development

Macrotidal estuaries of the inner Bay of Fundy are utilized by large numbers of migratory fishes, particularly dogfish, sturgeon, herring, shad, Atlantic salmon and striped bass as well as by other migratory marine animals, many of which have large body sizes (squid, Lamnid sharks, seals and whales). Tagging experiments indicate the fishes originate from stocks derived over the entire North American Atlantic coast from Florida to LaBrador. Population estimates suggest up to 2.0 × 10 6 adult American shad ( Alosa sapidissima) migrate through an individual embayment each year. These migrations are an integral part of the life history of the respective species and appear to be controlled in part by the near shore movements of ocean currents. In other regions of the world similar macrotidal estuaries exist (Cook Inlet, Alaska; Severn Estuary, U.K.) and they, like the Bay of Fundy, are linked in continuum to the local ocean currents. We propose that marine animals utilize all these regions in a manner similar to the Bay of Fundy estuaries and properly designed surveys will reveal their presence. Fish passage studies utilizing the Annapolis estuary low-head, tidal turbine on the Bay of Fundy have shown that turbine related mortality of 20-80% per passage occurs depending on fish species, fish size and the efficiency of turbine operation. We suggest that introduction of tidal turbines into open ocean current systems will cause widespread impact on marine populations resulting in significant declines in abundance.

Tidal power

Reviews the physics of tidal power, considering the gravitational effects of the Moon and Sun; semidiurnal, diurnal, and mixed tides; and major periodic components that affect the tidal range. Shelving, funneling, reflection, and resonance phenomena that have a significant effect on tidal range are also discussed. Basic parameters that govern the design of tidal power schemes in terms of mean tidal range and surface area of the enclosed basin are identified. Because energy extracted is proportional to the square root of the tidal amplitude, sites with large tidal amplitudes are best suited for tidal power developments, whereas sites with low tidal amplitudes have sluicing that may be prohibitive. Potential tidal energy developments are mentioned. Existing tidal energy plants are discussed. Tidal barrage design and construction using caissons is examined, as are alternative operating modes, development trends and possibilities, generation cost at the barrage boundary, sensitivity to discount rates, general economics, and markets. Environmental effects, and institutional constraints to the development of tidal barrage schemes are also discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Tidal power in Canada

This presentation examines the tidal power resource of Canada and its utilization. The topics of the presentation include target development sites for the Bay of Fundy, cost benefit analysis, comparison of sites and modes of energy storage, cost reduction, environmental effects, and an analysis of the overall feasibility of tidal power development in the Bay of Fundy.

Potential Impact of Large-Scale Tidal Power Developments in the Upper Bay of Fundy on Fisheries Resources of the Northwest Atlantic

Abstract Construction of large-scale, hydroelectric tidal power developments in the upper Bay of Fundy is receiving serious consideration. Potential designs involve ebb-generation with 1400- 5300-MW plants using 7.6 m diameter, straight-flow, low-head turbines installed in dams up to 8 km in length. Discharge through individual turbines will be 400 m3/second at 50 rev/minute with draft tube velocities of 11.4 m/second. Calculated parameters for these turbines are a water length of 2.26 m, impact velocity of 23.99 m/second, blade tip velocity up to 28.7 m/second and a total pressure flux of 1.7 atm. The existing environment is macrotidal (tide range 11–16 m). Embayments are homogeneous estuaries with extremely turbid water. The intertidal biological community is a salt marsh-mudflat biome. The pelagic zone supports large populations of migratory fishes, particularly the alosids, Alosa sapidissima, A. aestivalis, A. pseudoharengus, and Clupea harengus. Striped bass, spiny dogfish, Atlantic salmon, and Atlan...

Fundy Tidal Power Development and Potential Fish Production in the Gulf of Maine

The possible effects of tidal amplitudes altered by Fundy tidal power development upon potential fish production in the Gulf of Maine are examined with a marine ecosystem model. Three areas off the Maine coast are delineated on the basis of winds, tides, and the extent of vertical mixing. An optimum kinetic energy from wind and tide exists for maximum primary production in the water column. Primary production in the model is the base for a simple pelagic food chain leading from phytoplankton through zooplankton to fish. If the construction of a tidal power dam in the upper Bay of Fundy results in a 5–10% increase in tidal amplitude, our first-order model predicts that enhanced vertical mixing from May to October will increase potential fish production along the Maine west coast by 7–12%. Fish production along the Maine east coast and in offshore waters is predicted to remain at present levels. Climatic variation is predicted to have as large an impact on fish production as man-induced changes in vertical mixing caused by tidal power development.

Nodal Modulation of the Lunar Semidiurnal Tide in the Bay of Fundy and Gulf of Maine

Observations, numerical modeling, and theoretical calculations show how the 18.6-year modulation of the main lunar semidiurnal tide in the Bay of Fundy and Gulf of Maine is reduced from its astronomical value of 3.7 percent to 2.4 percent by the effects of friction and resonance. The agreement of the three approaches increases confidence in model predictions of widespread changes in the tidal regime resulting from development of tidal power.

Simple theory for designing tidal power schemes

Basic parameters governing the design of tidal power schemes are identified and converted to dimensionless form by reference to (i) the mean tidal range and (ii) the surface area of the enclosed basin. Optimum values for these dimensionless parameters are derived and comparison made with actual engineering designs. A theoretical framework is thus established which can be used (i) to make a rudimentary design at any specific location or (ii) to compare and evaluate designs for various locations. Both one-way (flood or ebb) and two-way (flood and ebb) schemes are examined and, theoretically, the two-way scheme is shown to be more efficient. However, in practice, two-way schemes suffer disadvantages arising from (i) two-way flow through both turbines and sluices and (ii) lower average turbine heads. An important dimensional aspect of tidal power schemes is that, while energy extracted is proportional to the tidal amplitude squared, the requisite sluicing area is proportional to the square root of the tidal amplitude. In consequence, sites with large tidal amplitudes are best suited to tidal power development whereas for sites with low tidal amplitudes sluicing costs may be prohibitive.

Integration of Ecological and Engineering Aspects in Planning Large Scale Tidal Power Development in the Bay of Fundy, Canada

Large-scale tidal power development in the Bay of Fundy has been given serious consideration for over 60 years. There has been a long history of productive interaction between environmental scientists and engineers durinn the many feasibility studies undertaken. Up until recently, tidal power proposals were dropped on economic grounds. However, large-scale development in the upper reaches of the Bay of Fundy now appears to be economically viable and a pre-commitment design program is highly likely in the near future. A large number of basic scientific research studies have been and are being conducted by government and university scientists. Likely environmental impacts have been examined by scientists and engineers together in a preliminary fashion on several occasions. A full environmental assessment will be conducted before a final decision is made and the results will definately influence the outcome.

Tides and tidal power in the Bay of Fundy

The Bay of Fundy in Eastern Canada has the highest tides in the world, with a range from low tide to high tide that can exceed 15 m in Minas Basin at the head of the Bay. Interest in harnessing these tides for the generation of electricity has raised challenging questions about the environmental impact of a tidal power development, and stimulated basic research which has elucidated the role of the tides in the general oceanography of the region.

Suspended Sediment Transport and Deposition Modeling in the Bay of Fundy, Nova Scotia — a Region of Potential Tidal Power Development

Two recent independent studies of the Minas Basin have been combined to produce a numerical simulation of suspended sediments. One study devised a numerical, barotropic tidal model of the Bay of Fundy and Gulf of Maine, which produced a good simulation of the tides and currents in the Minas Basin. The second, an extensive program of sediment sampling and monitoring addressed the nature of suspended sediments, bottom sediments, their various sediment sources and the postglacial evolution of the system. The only significant source of suspended sediment was from the open boundary to the Minas Basin and was of relatively uniform concentration through the water column. Consequently, the barotropic tidal model was well suited to modeling this material. Sediment laws describing sediment settling, resuspension, and the critical stress for entrainment were obtained from the literature and evaluated. The settling velocity of the suspended sediment was obtained by experimentation using actual water/sediment samples. Because the various parameters and critical stresses show a considerable variation among experimenters, runs were planned to examine a range of parameters. A close fit to existing conditions was obtained with the model generating mudflats in those regions where indeed they exist. Using the various parameters and critical stresses reflecting maximum sedimentation, the model was run to include the effects of a tidal power barrage off Economy Point. It is concluded that suspended sediment would not inhibit the operation of such a barrage through siltation directly in front of or behind the barrier. Increased siltation can be expected in the intertidal areas behind the barrage. Sediment budget considerations further limit the degree of post barrier siltation, insofar as the resident volume of suspended material (30 × 106 m3) is not enough to significantly reduce the headpond area.Key words: suspended sediment, sediment transport, numerical model, tide

Sediment distribution, circulation and provenance in a macrotidal bay: Garolim Bay, Korea

A study of the sedimentary regime in Garolim Bay has been carried out in connection with a feasibility study for tidal power development. At the mouth of the bay, sand is shown to be circulating round a central bank between an ebb and a flood channel. In the middle bay, clay and heavy-mineral distributions indicate a zone where finer sediments derived from offshore mix with those originating from the local streams. Quantities of land-derived sediments are presumed to be deposited near the shores during the rainy summer season and these are redistributed during the windy winter season, but the concentrations of suspended sediment are generally low. The influx of sediment appears to largely balance the increase in sea level. Siltation over the general area may not be seriously increased after construction of a barrage, but local siltation and scour near the barrage could be serious problems.