Good noise, bad noise: A tricky case of balancing risk of physical injury against acoustic disturbance for marine mammals and tidal energy devices

2017 ◽  
Vol 141 (5) ◽  
pp. 3921-3921
Author(s):  
Ben Wilson ◽  
Brett Marmo ◽  
Paul A. Lepper ◽  
Denise Risch ◽  
Steven Benjamins ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Tidal Energy ◽  
Physical Injury ◽  
Acoustic Disturbance ◽  
Energy Devices

scholarly journals Providing ecological context to anthropogenic subsea noise: Assessing listening space reductions of marine mammals from tidal energy devices

2019 ◽  
Vol 103 ◽  
pp. 49-57 ◽  
Author(s):  
Matthew K. Pine ◽  
Pál Schmitt ◽  
Ross M. Culloch ◽  
Lilian Lieber ◽  
Louise T. Kregting
Keyword(s):  
Marine Mammals ◽  
Tidal Energy ◽  
Ecological Context ◽  
Energy Devices

scholarly journals Passive acoustic methods for tracking the 3D movements of small cetaceans around marine structures

2020 ◽  
Author(s):  
Douglas Gillespie ◽  
Laura Palmer ◽  
Jamie Macaulay ◽  
Carol Sparling ◽  
Gordon Hastie
Keyword(s):  
Marine Mammals ◽  
New Technologies ◽  
Three Dimensional ◽  
Tidal Energy ◽  
Time Of Arrival ◽  
Marine Animals ◽  
Tidal Turbines ◽  
Wide Range ◽  
Tidal Turbine ◽  
Passive Acoustic

AbstractA wide range of anthropogenic structures exist in the marine environment with the extent of these set to increase as the global offshore renewable energy industry grows. Many of these pose acute risks to marine wildlife; for example, tidal energy generators have the potential to injure or kill seals and small cetaceans through collisions with moving turbine parts. Information on fine scale behaviour of animals close to operational turbines is required to understand the likely impact of these new technologies. There are inherent challenges associated with measuring the underwater movements of marine animals which have, so far, limited data collection. Here, we describe the development and application of a system for monitoring the three-dimensional movements of cetaceans in the immediate vicinity of a subsea structure. The system comprises twelve hydrophones and software for the detection and localisation of vocal marine mammals. We present data demonstrating the systems practical performance during a deployment on an operational tidal turbine between October 2017 and October 2019. Three-dimensional locations of cetaceans were derived from the passive acoustic data using time of arrival differences on each hydrophone. Localisation accuracy was assessed with an artificial sound source at known locations and a refined method of error estimation is presented. Calibration trials show that the system can accurately localise sounds to 2m accuracy within 20m of the turbine but that localisations become highly inaccurate at distances greater than 35m. The system is currently being used to provide data on rates of encounters between cetaceans and the turbine and to provide high resolution tracking data for animals close to the turbine. These data can be used to inform stakeholders and regulators on the likely impact of tidal turbines on cetaceans.

Influence of microstructural defects and hydrostatic pressure on water absorption in composite materials for tidal energy

2018 ◽  
Vol 52 (21) ◽  
pp. 2899-2917 ◽  
Author(s):  
DM Grogan ◽  
M Flanagan ◽  
M Walls ◽  
SB Leen ◽  
A Doyle ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Composite Materials ◽  
Hydrostatic Pressure ◽  
Water Absorption ◽  
Glass Fibre ◽  
Tidal Energy ◽  
Operating Conditions ◽  
X Ray ◽  
Energy Devices ◽  
X Ray Computed

The lifespan and economic viability of tidal energy devices are constrained, in part, by the complex degradation of the tidal turbine blade materials due to prolonged immersion in a hostile sub-sea environment. Seawater penetration is a significant degradation mechanism in composite materials. This work aims to investigate the influence of microstructure and hydrostatic pressure on water absorption in four polymer composites which are candidate materials for use in tidal energy devices. These materials are: a glass fibre powder epoxy, a carbon fibre powder epoxy, glass fibre Ampreg epoxy and a chopped fibre glass fibre Polyether Ether Ketone. X-ray computed tomography is used to characterise the voids, resin-rich areas and other manufacturing defects present in each material. These defects are known to significantly alter the rate of moisture diffusion, as well as the total uptake of water at saturation. The samples are then exposed to accelerated water aging and hydrostatic pressurisation in order to simulate a range of expected sub-sea operating conditions. The material micro-structure, the matrix material and pressurisation level are shown to strongly influence both the moisture absorption rate and total water uptake. Significant volumetric changes are also noted for all samples, both during and after aging. X-ray computed tomography scans of specimens also provide a unique insight into the role of voids in storing water once a material has reached saturation.

scholarly journals Collision risk modelling for tidal energy devices: A flexible simulation-based approach

2021 ◽  
Vol 278 ◽  
pp. 111484
Author(s):  
Nicholas Horne ◽  
Ross M. Culloch ◽  
Pál Schmitt ◽  
Lilian Lieber ◽  
Ben Wilson ◽  
...  
Keyword(s):  
Tidal Energy ◽  
Collision Risk ◽  
Risk Modelling ◽  
Energy Devices ◽  
Simulation Based

scholarly journals Marine Scour and Offshore Wind: Lessons Learnt and Future Challenges

2011 ◽  
Author(s):  
John M. Harris ◽  
Richard J. S. Whitehouse ◽  
James Sutherland
Keyword(s):  
Hazard Assessment ◽  
Wind Farms ◽  
Tidal Energy ◽  
Offshore Wind ◽  
Commercial Development ◽  
Offshore Wind Farms ◽  
Energy Devices ◽  
Lessons Learnt ◽  
Future Challenges ◽  
Scour Hazard

The drive for developing marine offshore renewables has led to specific requirements for scour hazard assessment relating to the associated foundation structures and the cabling necessary for in-field transmission and power export. To date within the United Kingdom (UK) a number of demonstrator projects have been constructed covering wind, wave and tidal generation. However, only offshore wind has been developed at large-scale at present as part of two rounds of commercial development of offshore wind farms (OWFs). In June 2008, The Crown Estate, responsible for licensing seabed use, announced proposals for a third round of offshore wind farms to develop an additional 25 GW of energy to the 8 GW already planned for under Rounds 1 and 2. The size of these Round 3 developments will vary, but the largest of these zones will involve the construction of around 2500 seabed foundation structures. Under Round 1 and 2 developments monopile and jacket type foundations have been used, although several other European (non UK) wind farms have been built using gravity base foundations. For a wind turbine the foundations may account for up to 35% of the installed cost. Therefore, one of the future challenges for large volume installation of offshore wind is the control and minimization of these costs. For tidal energy devices one of the principal requirements for many of the devices proposed is their placement in areas of strong tidal energy, and this has implications not only for the stability of the foundation option, but also for the construction methodology. Similarly wave energy devices are designed to be located in shallow, coastal environments as either floating or bottom mounted systems. These devices, by design, are intended to be located in environments with strong wave action. This may be substantial during storm events, which has implications for the integrity of the anchoring system keeping the wave device on station or the design of the device if it is seabed mounted. This paper will explore the lessons learnt from existing offshore wind farm developments as this represents the principal body of collected monitoring data. Using these data the paper will outline some of the challenges facing the offshore renewable industry in respect of the foundation designs and specifically the requirements for scour hazard assessment using the combined experience from those developments currently operational or under construction.

scholarly journals A sound approach to assessing the impact of underwater noise on marine fishes and invertebrates

2016 ◽  
Vol 74 (3) ◽  
pp. 635-651 ◽  
Author(s):  
Anthony D. Hawkins ◽  
Arthur N. Popper
Keyword(s):  
Particle Motion ◽  
Marine Mammals ◽  
Sound Pressure ◽  
Legal Protection ◽  
Future Research ◽  
Polar Regions ◽  
Underwater Noise ◽  
Aquatic Life ◽  
Energy Devices ◽  
The Impact

Increasing attention is being paid to the ecological consequences of underwater noise generated by human activities such as shipping and maritime industries including, but not limited to, oil and gas exploration and extraction, sonar systems, dredging and the construction of offshore renewable energy devices. There is particular concern over the extension of these activities into previously undeveloped areas of the oceans, including Polar Regions and areas of coral reef habitat. Most of the concern by regulators and others has focussed upon effects upon marine mammals and other protected species. However, examining the impacts upon the overall ecology of affected habitats is also important as it may be dominated by effects upon the far larger biomasses of fishes and invertebrates, which do not have the same degree of legal protection. Many of these assessments of the impact of noise on fishes and invertebrates have overlooked important issues, including the sensitivity of a substantial proportion of these species to particle motion rather than sound pressure. Attempts have been made to establish sound exposure criteria setting regulatory limits to the levels of noise in terms of effects upon mortality levels, injury to tissues, hearing abilities, behaviour, and physiology. However, such criteria have almost exclusively been developed for marine mammals. Criteria for fishes and invertebrates have often had to be assumed, or they have been derived from poorly designed and controlled studies. Moreover, the metrics employed to describe sounds from different sources have often been inappropriate, especially for fishes, and invertebrates, as they have been based on sound pressure rather than particle motion. In addition, the sound propagation models employed to assess the distances over which effects might occur have seldom been validated by actual measurements and are especially poor at dealing with transmission under shallow water conditions, close to or within the seabed, or at the surface. Finally, impacts on fish and invertebrate populations are often unknown and remain unassessed. This paper considers the problems of assessing the impact of noise upon fishes and invertebrates and the assessment procedures that need to be implemented to protect these animals and the marine ecosystems of which they form an integral part. The paper also suggests directions for future research and planning that, if implemented, will provide for a far better scientific and regulatory basis for dealing with effects of noise on aquatic life.

Life cycle comparison of a wave and tidal energy device

2011 ◽  
Vol 225 (4) ◽  
pp. 325-337 ◽  
Author(s):  
S Walker ◽  
R Howell
Keyword(s):  
Life Cycle ◽  
Wave Energy ◽  
Tidal Energy ◽  
Development Stage ◽  
Payback Period ◽  
Energy Device ◽  
Energy Mix ◽  
Energy Devices ◽  
Marine Energy ◽  
Marine Current

Tidal and wave energy devices are often discussed as a future contributor to the UK’s energy mix. Indeed, marine energy resources are said to have the potential to supply up to 20 per cent of the nation’s electricity demand. However, these technologies are currently at the development stage and make no meaningful contribution to the national grid. A number of devices have been developed, but no single method has emerged as the leading technology. This paper aims to compare two promising devices, one wave device and one tidal device, and assess the life cycle properties of each. A life cycle assessment of the Oyster wave energy device was conducted as part of this study, and a comparison of this and the SeaGen marine current turbine was undertaken. In both cases a ‘cradle-to-grave’ assessment was carried out, calculating emissions from materials, fabrication, transport, installation, lifetime maintenance, and decommissioning (including recycling). The SeaGen tidal device was calculated to have an energy payback period of 14 months, and a CO2 payback period of 8 months. The equivalent figures for the Oyster device were 12 and 8 months, respectively. The respective energy and carbon intensities for the two devices were 214 kJ/kWh and 15 gCO2/kWh for the SeaGen and 236 kJ/kWh and 25 gCO2/kWh for the Oyster. The calculated intensities and payback periods are close to those of established wind turbine technologies, and low relative to the 400–1000 g CO2/kWh of typical fossil fuel generation. With further developments in construction and deployment efficiency these intensities are expected to fall, so the devices appear to have the potential to offer a viable contribution to the UK’s future energy mix.

scholarly journals Grid Integration of Wave and Tidal Energy

2011 ◽  
Author(s):  
Anne Blavette ◽  
Dara L. O’Sullivan ◽  
Antony W. Lewis ◽  
Michael G. Egan
Keyword(s):  
Wind Energy ◽  
Dynamic Models ◽  
Dynamic Modelling ◽  
Tidal Energy ◽  
Energy Industry ◽  
Grid Integration ◽  
Ocean Energy ◽  
Major Barrier ◽  
Energy Devices ◽  
Grid Connection

Wave and tidal energy provide a renewable source of electricity. However, their inherent fluctuations may have a negative impact on the power quality of a local electrical network. Grid operators assess this impact through the use of dynamic models of the generation units, which are inserted into the overall power system model. Providing these models is a compulsory step for any power generator to procure a grid connection above a specified power capacity. Significant issues were encountered in the wind energy industry regarding the dynamic modelling of devices, among which were model numerical instability, poor dynamic model quality and model incompatibility. Considering the large diversity of device types in the emerging ocean energy industry, these problems are considered as a major barrier to the larger scale grid-integration of marine energy converters. Dynamic models must clearly demonstrate the compliance of the actual power generation device and array of devices to the grid code requirements for grid-connection to be allowed. A further barrier to grid connection of ocean energy devices is that existing grid codes — mainly written in the context of wind energy — may be irrelevant or inadequate for ocean energy devices. This paper presents an overview of these issues, and details a radically different approach to the dynamic modelling of ocean energy devices that will assist in overcoming the issues previously encountered in the development of wind turbine models. It also highlights the gaps and inadequacy regarding grid code requirements for ocean energy devices, and provides some recommendations for a new ocean energy grid code.

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