Tidal energy leasing and tidal phasing

Neill, Simon P.; Hashemi, M. Reza; Lewis, Matt

doi:10.1016/j.renene.2015.07.016

Cited by 65 publications

(36 citation statements)

References 27 publications

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“…The maximum power available from all location is 12.85 GW (Figure ), which is only slightly less than summing up the maximum power from each location (14.83 GW, see Table ). This tells us that the peak power occurs almost at the same time in all locations, indicating minimal phase diversity among these high tidal energy sites, as also found by Neill et al (). This will provide an intermittent availability of power.…”

Section: Resultssupporting

confidence: 82%

Comparative Effects of Climate Change and Tidal Stream Energy Extraction in a Shelf Sea

2018

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The environmental implications of tidal stream energy extraction need to be evaluated against the potential climate change impacts on the marine environment. Here we study how hypothetical very large tidal stream arrays and a business as usual future climate scenario can change the hydrodynamics of a seasonally stratified shelf sea. The Scottish Shelf Model, an unstructured grid three-dimensional ocean model, has been used to reproduce the present and the future state of the NW European continental shelf. Four scenarios have been modeled: present conditions and projected future climate in 2050, each with and without very large scale tidal stream arrays in Scottish Waters (UK). It is found that where tidal range is reduced a few centimeters by tidal stream energy extraction, it can help to counter extreme water levels associated with future sea level rise. Tidal velocities, and consequently tidal mixing, are also reduced overall by the action of the tidal turbine arrays. A key finding is that climate change and tidal energy extraction both act in the same direction, in terms of increasing stratification due to warming and reduced mixing; however, the effect of climate change is an order of magnitude larger.Plain Language Summary Tidal currents can turn underwater turbines, which can generate electricity. Tides in Scotland (United Kingdom, UK) can provide 10% of the present UK electricity demand. Does this come without side effects on the marine environment? The answer is no, but those side effects are going to be local and much smaller than the effects of climate change. We do not have a time machine, but we can use a numerical ocean model, a computer software that is able to predict the movement of ocean currents, among other things. We can simulate the present and future conditions in 2050 of the North and Irish Seas, with and without the ocean bottom being covered in some areas with underwater turbines. Our predictions tell us that the underwater turbines will slow down the ocean currents. This leads to a less vertical mixing of the ocean, reducing the exchange of water between the ocean bottom and the surface. However, the ocean model also anticipates that global warming will have the same effect, but 10 times larger. We discovered that the underwater turbines can also change the sea level, and, in some situations, this can help to protect the coast against future sea level rise.

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Section: Resultssupporting

confidence: 82%

Comparative Effects of Climate Change and Tidal Stream Energy Extraction in a Shelf Sea

2018

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“…Due to the amount of TCP output is small and semi-diurnal intermittency of tidal current at the turbine deployment site in the Kinmen coastal waters; it might be possible to conduct storage into the supergrid [15,55]. Besides, Neill et al [56] proposed that optimization of the TCP and finding the optimal site for parallel development for relative low number of arrays are import for large scale exploitation of TCP and should be conducted in the future work.…”

Section: Discussion and Future Workmentioning

confidence: 99%

Tidal Current Power Resources and Influence of Sea-Level Rise in the Coastal Waters of Kinmen Island, Taiwan

Chen

Lin

et al. 2017

Energies

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Abstract:The tidal current power (TCP) resource, the impact of TCP extraction on hydrodynamics and the influence of sea-level rise (SLR) on TCP output in the coastal waters of Kinmen Island (Taiwan) are investigated using a state-of-the-art unstructured-grid depth-integrated numerical model. The model was driven by eight tidal constituents extracted from a global tidal prediction model and verified with time series of measured data for tide level and depth-averaged current. The simulations showed reasonable agreement with the observations; the skill index was in the excellent (0.71-0.93) range with regard to simulating tide level and currents. Model predictions indicated that the channel between Kinmen and Lieyu serves as an appropriate site for deploying the tidal turbines because of its higher tidal current and deeper water depth. The bottom friction approach was utilized to compute the average TCP over a spring-neap cycle (i.e., 15 days). Mean TCP reached its maximum to 45.51 kW for a coverage area of 0.036 km 2 when an additional turbine friction coefficient (C t ) increased to 0.08, and a cut-in speed of 0.5 m/s was used. The annual TCP output was estimated to be 1.08 MW. The impact of TCP extraction on the change in current is significant, with a maximum reduction rate of instant current exceeding 60%, and the extent of influence for the average current is 1.26 km in length and 0.30 km in width for the −0.05 m/s contour line. However, the impact of TCP extraction on the change in tide level is insignificant; the maximum change in amplitude is only 0.73 cm for the K 2 tide. The influence of SLR on the TCP output in Kinmen waters was also estimated. Modeling assessments showed that due to SLR produces faster tidal current, the annual TCP output increased to 1.52 MW, 2.01 MW, 2.48 MW and 2.97 MW under the same cut-in speed and coverage area conditions when SLR 0.25 m, SLR 0.5 m, SLR 0.75 m and SLR 1.0 m were imposed on the model.

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“…It may even be possible to exploit the phase differences between sites to compensate, to a certain extent, for temporal variations and thereby produce a more regular power supply (e.g. Hardisty 2008;Iyer et al 2013;Neill et al 2016). …”

Section: Temporal Variations In Available Powermentioning

confidence: 99%

Assessment of the Malaysian tidal stream energy resource using an upper bound approach

Bonar

Schnabl

Lee

et al. 2018

J. Ocean Eng. Mar. Energy

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In this paper, an upper bound approach is used to determine the maximum power available to tidal stream turbines placed at five sites along the west coast of Peninsular Malaysia. A depth-averaged hydrodynamic model of the Malacca Strait is built and validated against field measurements. Actuator disc theory is then used to introduce rows of tidal stream turbines as line sinks of momentum and to determine the maximum time-averaged power available to rows of both moderately sized and very large turbines, placed strategically at the locations of highest naturally occurring kinetic energy flux. Results suggest that although the Malaysian tidal stream energy resource is not large enough to make a significant contribution to the country's energy mix, there may yet be opportunities to use low-speed tidal turbines in small-scale and off-grid electricity generation schemes. Methods are described in detail and links to source codes and results are provided to encourage the application of this simple, yet effective resource assessment methodology to other promising tidal energy sites.

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Tidal energy leasing and tidal phasing

Cited by 65 publications

References 27 publications

Comparative Effects of Climate Change and Tidal Stream Energy Extraction in a Shelf Sea

Comparative Effects of Climate Change and Tidal Stream Energy Extraction in a Shelf Sea

Tidal Current Power Resources and Influence of Sea-Level Rise in the Coastal Waters of Kinmen Island, Taiwan

Assessment of the Malaysian tidal stream energy resource using an upper bound approach

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