Tidal Barrage Research Articles

Determination of Potential Tidal Power Sites at East Malaysia

Tidal range energy is one of the most predictable and reliable sources of renewable energy. This study’s main aim is to determine potential sites for tidal range power in East Malaysia, by analyzing tidal range distributions and resources and the feasibility of constructing barrages. Investigation was conducted in 34 sites, estimating their potential energy outputs and studying their areas for constructing barrages. Only 18 sites were marked as appropriate for constructing a tidal range energy extraction barrage. The highest potential power was found in Tanjung Manis, and its maximum capacity was calculated as 50.7kW. The second highest potential of tidal power extraction was found in Kuching Barrage at Pending, where an energy harvester could produce electric power up to 33.1kW.

Modelling the impact of tidal range energy on species communities

Tidal energy has the potential to form a key component of the energy production in a number of countries, including the UK. Nonetheless, the deployment of tidal energy systems is associated with potential environmental impacts as prime resource sites often coincide with unique ecosystems inhabited by sensitive organisms. Previous studies have generally focused on the hydrodynamic impact of tidal energy schemes, i.e. how schemes alter the flow dynamics and sedimentary transport processes. Whilst these efforts are key in understanding environmental impacts, there is no straightforward step for translating sediment to faunal changes. Species distribution models offer methods to quantitatively predict certain possible impacts of tidal energy extraction. The River Severn is a distinguished candidate region for tidal energy in the UK featuring sites under stringent ecological protection regulations. We examine the impact of a proposed Severn tidal barrage on 14 species via the linking of hydrodynamic modelling to species distribution models. Through a selection of species that are linked via a simple food web system we extrapolate changes in prey species to the respective predator species. We show that species at lower trophic levels would be adversely affected by the barrage, but higher trophic level organisms increase in possible habitable area. Once food web relationships are acknowledged this increase in habitat area decreases, but is still net positive. Overall, all 14 species were affected, with most gaining in distribution area, and only four losing distribution area within the Severn Estuary. We conclude that a large-scale tidal barrage may have detrimental and complex impacts on species distribution, altering food web dynamics and altering food availability in the Severn Estuary. The methodology outlined herein can be transferred to the assessment and optimisation of prospective projects globally to aide in the sustainable introduction of the technology.

On the potential of linked-basin tidal power plants: An operational and coastal modelling assessment

Single-basin tidal range power plants have the advantage of predictable energy outputs, but feature non-generation periods in every tidal cycle. Linked-basin tidal power systems can reduce this variability and consistently generate power. However, as a concept the latter are under-studied with limited information on their performance relative to single-basin designs. In addressing this, we outline the basic principles of linked-basin power plant operation and report results from their numerical simulation. Tidal range energy operational models are applied to gauge their capabilities relative to conventional, single-basin tidal power plants. A coastal ocean model (Thetis) is then refined with linked-basin modelling capabilities. Simulations demonstrate that linked-basin systems can reduce non-generation periods at the expense of the extractable energy output relative to conventional tidal lagoons and barrages. As an example, a hypothetical case is considered for a site in the Severn Estuary, UK. The linked-basin system is seen to generate energy 80–100% of the time over a spring-neap cycle, but harnesses at best ≈ 30% of the energy of an equivalent-area single-basin design.

Temporal Evolution Assessment of Dynamic Tidal Power Including Turbine Effects

Dai, P.; Zhang, J., and Xiao, L., 2020. Temporal evolution assessment of dynamic tidal power including turbine effects. Journal of Coastal Research, 36(5), 1050–1058. Coconut Creek (Florida), ISSN 0749-0208.The dynamic tidal power system adopts a coast perpendicular dike in capturing tidal potential energy and is basin free as opposed to the conventional tidal barrage system. Since it is important for the developers to have detailed information of the power output characteristics prior to implementation, the temporal evolution of the power output has been studied to improve the understanding of the dynamic tidal power resource using a two-dimensional hydrodynamic model. The model accurately simulates the tidal motion characteristic of Chinese marginal seas. As an essential input for the temporal power estimation, the turbine operation is taken into account for this study, while the watertight dike has often been considered in previous feasibility studies. The results show that the monthly average power output increases, reaches a maximum, and then decreases with an increase in the number of turbines. The temporal evolution of power is featured by strong semidiurnal intermittency due to the semidiurnal tide. The peak power is recorded as 2.81 GW during spring tide, when 8% of the dike is opened for turbines. The magnitude reduces in both the middle and neap tide stages. Four peaks in the monthly average hourly power variation histogram were picked up, with much more homogeneity as compared with the power series during any specific tidal stage. Structurally, the T-branch added to the seaward tip of the I-shaped system is called the T end and forms the T-shaped system. It is proposed that this T-shaped system leads to an increase in production. The T end harvests substantially greater M2 energy than K1 energy near the seaward end of the system. The concentration of M2 energy contributes to the improvement in power production.

Operating conditions leading to crack propagation in turbine blades of tidal barrages. Influence of head and operating mode

Tidal energy systems and specifically tidal barrages are renewable energy systems, that use the potential energy of tides to produce electricity. Actually, there are few tidal power stations operating, although recent studies show the potentiality of installing new units in a recent future due to the constant improvement of the technology related. As in other conventional hydropower systems, the runner is one of the critical components of the unit as it has to withstand an extreme wide range of relative head and two main operating modes (ebb and flood). Therefore, fatigue problems and undesirable failures are more likely to occur. Based on the analysis of a crack found in one of the blades of a prototype, this paper analyzes and discusses under which operating conditions the runner is more likely to suffer from fatigue problems. CFD and FEM simulation models have been used to determine the stress hotspots, which approximate very well the point where the real crack was initiated. Based on a probabilistic approach of an existing initial defect or flaw, the reliability of the blades, or the probability of not growing a crack and therefore last an infinite life, has been calculated for a wide range of operating conditions. While fatigue problems have been deeply discussed and analyzed in conventional turbines, the flow excitation characteristics in these units exhibit important differences and therefore the discussion and results provided in this paper could be useful for future designs and fatigue analyses of tidal turbines.

Opportunities for tidal range projects beyond energy generation: Using Mersey barrage as a case study

Currently there is renewed interest in harnessing the vast tidal resource to combat the twin challenges of climate change and energy security. However, within the UK no tidal barrage proposals have passed the development stage, this is due to a combination of high cost and environmental concerns. This paper demonstrates how a framework, such as the North West Hydro Resource Model can be applied to tidal barrages, with the Mersey barrage as a case study. The model materialised in order to provide developers with a tool to successfully identify the capacity of hydropower schemes in a specific location. A key feature of the resource model is the understanding that there is no single barrier to the utilisation of small hydropower but several obstacles, which together impede development. Thus, this paper contributes in part to a fully holistic treatment of tidal barrages, recognising that apart from energy generation, other environmental, societal and economic opportunities arise and must be fully investigated for robust decision-making. This study demonstrates how considering the societal needs of the people and the necessity for compensatory habitats, for example, an organic architectural design has developed, which aims to enhance rather than detract from the Mersey.

The impact of a tidal barrage on coastal flooding due to storm surge in the Severn Estuary

The proposed Severn Barrage is a controversial but widely discussed proposal to generate clean and renewable energy. A key concern with this technology is that such structures may cause other environmental problems. However, such structures might also have beneficial environmental effects in some areas, such as mitigating coastal flooding from storm surges. In this paper, we model the hydrodynamics of the Severn Barrage and surrounding area using a depth-averaged numerical model. We simulate a storm surge event based on realistic meteorological conditions coinciding with a spring tide. We find that to the east of the barrage the peak water level is significantly reduced by the barrage. To the west of the barrage, on the ocean side, the presence of the barrage leads to a small increase in the water levels during a surge event despite the reduction in the tidal amplitude. We examine different operational strategies for the barrage during a storm event—these make a small but perhaps significant difference. Overall, a barrage can help to mitigate the impact of storm surges on coastal flooding.

Perspective and Prospect of Tidal Electricity Generation in Iraq

or a long time, Iraq has been suffering from environmental pollution and electricity crisis. Therefore, tidal energy is one of the best renewable sources should be used to solve together the environmental pollution and electricity crisis. Tidal energy is usually available in coastal areas. Southern of Iraq has coastal areas in Basra Governorate on the northern Arabian Gulf. Therefore, this study has been investigated the possibility of establishing tidal power stations in two locations in Basra, Um Qasr and Al-Faw. In the case of the construction of a 4km2 tidal barrage in Um Qasr, the electricity generated was 98.85MW and 197.69MW to meet the demand for electricity in Basra by 6.59% and 13.18% in the case of one-way and two-way generation, respectively. While in case of construction of a 4km2 tidal lagoon in Al-Faw, the electricity generated was 31.37MW and 62.73MW to meet the demand for electricity in Basra by 2.09% and 4.18% in the case of one-way and two-way generation, respectively. So, this study clearly shows that tidal energy can contribute significantly to relief the electricity crisis in Basra Governorate.

Dynamic Behavior of Floating Tidal Current Power Device Considering Turbine Specifications

Tidal current power is one of the energy sources of the ocean. Electricity can be generated by converting the flow energy of the current into the rotational energy of a turbine. Unlike tidal barrage, tidal current power does not require dams, which have a severe environmental impact. A floating-type tidal current power device can reduce the expensive support and installation cost, which usually account for approximately 41% of the total cost. It can also be deployed in relatively deep water using tensioned wires. The dynamic behavior of a floater and turbine force are coupled because the thrust and moment of the turbine affect the floater excursion, and the motion of the floater can affect the incoming speed of the flow into the turbine. To maximize the power generation and stabilize the system, the coupled motion of the floater and turbine must be extensively analyzed. However, unlike pile-fixed devices, there have been few studies involving the motion analysis of a moored-type tidal current power device.In this study, the commercial program OrcaFlex 10.1a was used for a time domain motion analysis. In addition, in-house code was used for an iterative calculation to solve the coupled problems. As a result, it was found that the maximum mooring load of 200 kN and the floater excursion of 5.5 m were increased by the turbine effect. The load that occurred on the mooring system satisfied the safety factor of 1.67 suggested by API. The optimum mooring system for the floating tidal current power device was suggested to maximize the power generation and stability of the floater.

A SOLUTIONS APPRAISAL TOOL TO ADDRESS THE ENVIRONMENTAL IMPACTS OF TIDAL LAGOONS

The deployment of renewable energy is regarded as a strategy to combat climate change. There have been a number of global agreements aiming to mitigate climate change, the most recent of which was the 2015 Paris Agreement. Often overlooked is the vast amount of marine renewable energy available around the world’s coastlines. In particular tidal range energy is a largely untapped resource which has benefits including reduced uncertainty through use of proven technology, a high level of predictability, the ability to phase shift energy to provide base load supply and a long expected life span (100 years). The key barriers to development of tidal range energy have been environmental concerns and high capital cost. Tidal lagoons are often presented as environmentally friendly alternatives to tidal barrages, but this does not mean their environmental impacts can be overlooked. Recent developments in the UK lagoon industry such as the awarding of a Development Consent Order to Swansea Bay tidal lagoon, mean it is now more important than ever to consider the environmental impacts of tidal lagoons and what solutions are available to address them. This is challenging considering there are no operational tidal lagoons in the world yet. This study aims to: 1. Identify the key impacts through industry engagement 2. Find available solutions through systematic review 3. Select and analyze solutions using Multi Criteria Decision Analysis (MCDA), Cost Benefit Analysis (CBA) and Ecosystem Service Valuation (ESV).

A systematic review of transferable solution options for the environmental impacts of tidal lagoons

Tidal lagoons are presented as an environmentally friendly alternative to tidal barrages. This does not mean that their environmental impacts can be overlooked. A UK government review recommended a pilot scheme lagoon go ahead, with careful environmental monitoring. Despite recent government rejection of a lagoon scheme, it is still more important than ever to consider environmental solution options for any future lagoon developments. There are no operating lagoons in the world and so their environmental impacts are not fully understood. However, there is a vast quantity of literature available from other industries addressing similar impacts in the coastal, ocean and river environments. This systematic review follows the PRISMA and CEE guidance. Using this methodology the available literature covering relevant solution options from other industries that could be applied to future lagoon developments was quantified. This presents an investigation into solution options only, giving a quantitative analysis of what resources are available, how this compares to industry understanding, where the expertise lies globally, what impacts are being addressed and how applicable the solutions are for lagoon application. This paper analyses the extent and relevance of this available research on solutions as a resource for the nascent lagoon industry. Over half of the solutions found in this review require only small shifts in development for them to be realistic solution options for the lagoon industry in the future. This review opens the door on a vast and valuable resource and justifies the need for further investigation into solutions for the lagoon industry.

Development of a low head tidal turbine

Recent research has shown that four-quadrant turbines are required to achieve maximum net energy production in a tidal barrage plant. These turbines can generate electricity in both flow directions and are capable of pumping. An innovative turbine concept is being reviewed in the course of the Eurostars research project Safe*Coast. This project proposes to install a turbine in a reversible cylinder in order to allow for fourquadrant operation. To evaluate the feasibility of the concept, the authors designed a compact low head axial tidal turbine with the aid of CFD simulations. This paper presents the methods used in the design and optimization process of the turbine. It also describes numerically obtained turbine characteristics, and cavitation limits. The most critical requirements of the turbine include high efficiency in turbine and pumping mode and safe cavitation properties. By computing steady state CFD simulations of the turbine stage, an extensive set of geometries was analyzed. The authors optimized the turbine performance by adjusting the meridional section, as well as runner blade and guide vane profiles and angles along with other related parameters. Transient simulations of the whole setup, including the inlet and draft tube geometries, were performed in order to study transient effects. The final design after optimization is a three bladed axial turbine with adjustable guide vanes and a rim generator. The turbine’s symmetrical inlet and outlet geometry and its relative compactness permit its integration in a reversible cylinder. The simulation results are very positive and indicate that all the relevant design criteria are satisfied. As a result, the project will continue into a new phase in which a model of the turbine will be built for physical testing in order to verify the results and to conduct further investigations.

The Application of Dynamic Tidal Power in Korea

Park, Y.H., 2018. The Application of Dynamic Tidal Power in Korea In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1306–1310. Coconut Creek (Florida), ISSN 0749-0208.Tidal power is attractive as a predictable renewable energy, but it requires a high tidal range. The west coast of Korea is a place where the extreme tidal range is observed, so various studies have been conducted. The largest tidal power, Sihwa Tidal Power Station was successfully built and operated there. However, subsequent projects have been postponed or cancelled due to environmental issues. Dynamic Tidal power (DTP) is an alternative way to a conventional tidal barrage system. Because DTP has to be a huge structure to produce diffraction of tides, it was tested by a numerical model. The 2D numerical model ADCIRC was used in the simulation. DTP was simulated in the largest tidal range of the Korean coast and it was examined in various ways. DTP generates power by the phase difference of tide and it is available even in a small tidal range. The tidal difference between the front and back of DTP becomes maximized on 180 degrees out of phase theoretically. Though the phase difference also increased with the length of DTP structure, it could not reach 180 degrees out of phase even at the DTP length of 50 km. Because the length of DTP structure should be longer than tens of kilometers considering the length of tide, it may cause economic and environmental issues. The phase difference was varied along DTP and it was increasing as the location of measurement moved closer to the coast. When the required length of DTP is optimized, it would be more practical. The study focused on the reduction of the DTP length and some shapes were suggested finally.

Lightweight steel tidal power barrages with minimal environmental impact: application to the Severn Barrage.

For tidal power barrages, a breast-shot water wheel, with a hydraulic transmission, has significant advantages over a conventional Kaplan turbine. It is better suited to combined operations with pumping that maintain the tidal range upstream of the barrage (important in reducing the environmental impact), and is much less harmful to fish. It also does not require tapered entry and exit ducts, making the barrage much smaller and lighter, so that it can conveniently be built in steel. For the case of the Severn Estuary, UK, it is shown that a barrage at Porlock would generate an annual average power of 4 GW (i.e. 35 TWh yr-1), maintain the existing tidal ranges upstream of it and reduce the tidal ranges downstream of it by only about 10%. The weight of steel required, in relation to the annual average power generated, compares very favourably with a recent offshore wind farm.

Evaluation of Potential Sites for Harnessing Tidal Energy around Coastal Area of Malaysia

This paper present the potential sites around coastal area of Malaysia for electricity generation by harnessing tidal energy. As the electricity demand increase over the year and generating electricity by using fossil fuel caused the increase number in CO2 emission, thus renewable energy become one of the solution for alternating energy for electricity. There are a few of identified locations along Malaysia’s coastal area that have potential for tidal energy implementation. The approaching for harnessing tidal energy are by using tidal barrage approach which are consist three types of mode generation ebb-mode, flood-mode and double-mode. The output generations are calculated by identify the size of basin at identified locations. For suitable location identification is by using geographical map and bathymetry map. At the end, the identified location that suitable for harnessing tidal energy are Pulau Langkawi, Pulau Pinang, Lumut, Miri, Kota Kinabalu, Kudat, Lahad Datu, Tawau and Labuan.

Connectivity, migration and recruitment in a catadromous fish

Understanding the influence of river hydrology and connectivity on the migration and recruitment of diadromous fishes is fundamental for species management and conservation. We investigated the downstream catadromous spawning migration of adult female congolli (Pseudaphritis urvillii) using acoustic telemetry, and subsequent juvenile recruitment, in the lower reaches of the River Murray, Australia, in 2009–2011. The years 2009 and 2010 were characterised by diminished freshwater flow, closure of tidal barrages, and disconnection of freshwater and estuarine habitats; however, a navigation lock was operated to facilitate downstream fish passage in 2010. In both years, >70% of individuals tagged upstream undertook downstream migrations, in association with day-of-the-year (June–July) and moonphase (full), and accumulated upstream of the tidal barrages. In 2009, fish were unable to pass the barrages and remained upstream, but in 2010, an estimated >15000 individuals passed through the navigation lock, including 40% of individuals tagged upstream. These transitioned rapidly (<24h) through the estuary and into the ocean. In association, abundances of upstream migrant juveniles in spring–summer 2010–2011 were up to 180 times greater than in spring–summer 2009–2010. Our study illustrates the potential impact of tidal barriers on migrations and population dynamics of catadromous fish, and the importance of understanding species-specific migration ecology.

Multi-criteria decision-making on assessment of proposed tidal barrage schemes in terms of environmental impacts

For tidal range power plants to be sustainable, the environmental impacts caused by the implement of various tidal barrage schemes must be assessed before construction. However, several problems exist in the current researches: firstly, evaluation criteria of the tidal barrage schemes environmental impact assessment (EIA) are not adequate; secondly, uncertainty of criteria information fails to be processed properly; thirdly, correlation among criteria is unreasonably measured. Hence the contributions of this paper are as follows: firstly, an evaluation criteria system is established from three dimensions of hydrodynamic, biological and morphological aspects. Secondly, cloud model is applied to describe the uncertainty of criteria information. Thirdly, Choquet integral with respect to λ-fuzzy measure is introduced to measure the correlation among criteria. On the above bases, a multi-criteria decision-making decision framework for tidal barrage scheme EIA is established to select the optimal scheme. Finally, a case study demonstrates the effectiveness of the proposed framework.

Reassessment of tidal energy potential in India and a decision-making tool for tidal energy technology selection

Oceans have significant renewable energy options to provide environmental friendly and clean energy. Technology for ocean energy systems and the feasibility for extraction of the same is an important area on which research is being focused worldwide. This article covers a detailed review of available tidal energy conversion technologies and case studies, with specific focus on tidal power potential in India. The proven option for tidal energy conversion is barraging. Recently, open-type turbine (usually known as tidal stream turbines) has been studied by several researchers and pilot demonstrations have been made. While conventional turbines of 10–20 MW rating are used in barrages, the application of tidal stream turbines of 0.5–2.0 MW has been demonstrated in water depths between 40 and 60 m. A new scale is proposed for categorizing the tidal energy potential in terms of tidal velocity and tidal range which could be used to categorize the potential sites and their ranking. A new systematic approach proposed for the assessment of tidal energy conversion potential can facilitate the suitability of either tidal stream energy or tidal barrage for a location. Within this, one could also decide the site could be developed as a major project or minor project. Therefore, the present work will be useful for engineers and decision makers in technology selection investment potential identification.

Two Canals, Two Barrages and the Remnants of a River: Nature and Technology Along the Eider, Schleswig-Holstein's Longest River

Abstract The construction of the Eider Canal (build between 1774 and 1784) and especially of the Kiel Canal (1886-1895) had severe consequences for the river Eider. Most notably a vicious circle was generated whose main elements were growing sedimentation, the growing impact of the North Sea tides far upstream and increasingly catastrophic floods. After decades of planning, a tidal barrage began operating in 1938. Instead of bringing relief to the suffering residents it only deepened the crisis. Sedimentation increased even more until sand clogged the riverbed almost completely. The devastating storm flood of 1962 mobilised political and financial support to realise a plan engineers had been developing since the early twentieth century. Between 1967 and 1973 the Eider was dammed off in the estuary and a floodgate today controls the river's hydrology. The Eider was once Schleswig-Holstein's longest river. Today it has become a collection of disconnected watercourses. The article understands the river's history as a story of escalation: building projects (canals, dykes and a tidal barrage) along the Eider's banks had unintended ecological consequences. Lacking a clear understanding of hydrology, new constructions did not help, but only caused new complications. It is also a story with a distinct ending, as the Eider Barrage of 1973 subjects the river to technological control.

Exploring the implications of tidal farms deployment for wetland-birds habitats in a highly protected estuary

Next generation turbines can be installed to exploit tidal energy resource in estuaries. However, the ecological implications of such deployments remain unknown. Accordingly, this study is focused on the impact of tidal farms on intertidal areas and associated waterbird habitats in estuaries. A numerical model simulates the hydrodynamic conditions of the Solway Firth, comprising one of the most extensive intertidal zones in the UK. The effects of tidal farms with different turbine densities have been evaluated in terms of changes to the areas of habitat for wetland bird species of conservation importance. The results suggest that any habitat loss may be minor and that in some cases there may be an increase (also small) in the area of important habitat. The percentage change in intertidal areas is also considerably lower than that expected to result from tidal barrages of similar capacities, implying the potential for tidal farms to present an alternative solution for exploiting tidal energy in highly protected areas. The changes in the extent of intertidal habitat are not proportional to the energy dissipated by the tidal farm. Therefore a range of tidal farm designs should be evaluated in order to optimise installed capacity while minimising habitat loss. However, the site-dependency of the impacts and the complex responses to change of estuarine ecosystems reinforce the requirement for detailed studies to be undertaken for each specific location and array configuration. The methodology presented here is appropriate for such assessments as it can be applied to different locations and turbine types.