Coastal and Offshore Energy

Identifying relevant scales of variability for monitoring epifaunal reef communities at a tidal energy extraction site

O’Carroll JPJ, Kennedy RM, Savidge G. Identifying relevant scales of variability for monitoring epifaunal reef communities at a tidal energy extraction site. Ecological Indicators [Internet]. 2017 ;73:388 - 397. Available from: http://www.sciencedirect.com/science/article/pii/S1470160X1630591X
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

The SeaGen tidal energy turbine is located in the Strangford Narrows, Northern Ireland. The Narrows are designated as a Natura 2000 site, host unique biological assemblages and exhibit very high tidal velocities.

This study describes an asymmetrical BACI design monitoring program that was aimed at assessing the potential impact the SeaGen may have on epifaunal boulder reef communities. This study presents a novel methodology for monitoring epifaunal communities within highly variable and poorly understood tidal rapid environments.

We identify bare rock as a key measure of disturbance within tidal energy extraction sites and propose a new successional model for epifaunal reef communities on subtidal stable substrates. We also present an Ecological Quality Ratio (EQR); the High Energy Hard Substrate (HEHS) index for use in monitoring programs within tidal energy extraction sites.

Seasonality significantly affected epifaunal community structure, bare rock distributions and EQR values at all stations equally over time. SeaGen is not significantly affecting epifaunal community structure, bare rock distributions or EQR values at the impact site. The HEHS index has the potential to standardise benthic monitoring in tidal energy extraction sites.

Wave energy resource assessment along the Southeast coast of Australia on the basis of a 31-year hindcast

Morim J, Cartwright N, Etemad-Shahidi A, Strauss D, Hemer M. Wave energy resource assessment along the Southeast coast of Australia on the basis of a 31-year hindcast. Applied Energy [Internet]. 2016 ;184:276 - 297. Available from: http://www.sciencedirect.com/science/article/pii/S0306261916313666
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

In this study, a long-term assessment of the wave energy resource potential for the Australian southeast shelf is performed from deep to shallow water, based on a 31-year wave hindcast. The hindcast, covering the period from 1979 to 2010, has been performed at high spatio-temporal resolution with the wave energy transformation model SWAN using calibrated source-term parameters. The model has been applied with a variable spatial resolution of up to approximately 500 m and at 1 h temporal resolution and driven with high-resolution, non-stationary CFSR wind fields and full 2D spectral boundary conditions from WaveWatch III model. Model validation was conducted against wave measurements from multiple buoy sites covering 10–31 years and showed a relatively high correlation between hindcast and measured significant wave height (Hs) and mean wave direction (θm).

Maps of wave power resource distribution for annual and seasonal mean potential were generated along with the maps of resource reliability and variability. The high resolution allowed us to perform in-depth analysis of wave power characteristics, providing resource knowledge on seasonal and longer-term variability necessary for reliable and optimal design of wave technology. The most promising area for wave power exploitation was found to be the central coast of New South Wales, where various high-energy hotspots were selected for a further analysis. For each of the considered hotspots, the wave power magnitude, variability and consistency were carefully assessed and characterized by means of sea state parameters and mean wave directions. Finally, estimates of electric power outputs from different types of pre-commercial wave energy converter devices were drawn for each hotspot based on the wave data hindcast and discussed.

A Spatial-Economic Cost-Reduction Pathway Analysis for U.S. Offshore Wind Energy Development from 2015–2030

Beiter P, Musial W, Smith A, Kilcher L, Damiani R, Maness M, Sirnivas S, Stehly T, Gevorgian V, Mooney M, et al. A Spatial-Economic Cost-Reduction Pathway Analysis for U.S. Offshore Wind Energy Development from 2015–2030. Golden, CO: National Renewable Energy Laboratory; 2016.
Freely available?: 
Yes
Summary available?: 
No
Type: Report

This report describes a comprehensive effort undertaken by the National Renewable Energy Laboratory (NREL) to understand the cost of offshore wind energy for markets in the United States. The study models the cost impacts of a range of offshore wind locational cost variables for more than 7,000 potential coastal sites in U.S. offshore wind resource areas. It also assesses the impact of more than 50 technology innovations on potential future costs for both fixed- bottom and floating wind systems. Comparing these costs to an initial site-specific assessment of local avoided generating costs, the analysis provides a framework for estimating the economic potential for offshore wind. The analysis is intended to inform a broad set of stakeholders and enable an assessment of offshore wind as part of energy development and energy portfolio planning. It provides information that federal and state agencies and planning commissions could use to inform initial strategic decisions about offshore wind developments in the United States. 

Moving from consultation to participation: A case study of the involvement of fishermen in decisions relating to marine renewable energy projects on the island of Ireland

Reilly K, O'Hagan AMarie, Dalton G. Moving from consultation to participation: A case study of the involvement of fishermen in decisions relating to marine renewable energy projects on the island of Ireland. Ocean & Coastal Management [Internet]. 2016 ;134:30 - 40. Available from: http://www.sciencedirect.com/science/article/pii/S0964569116302253
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

The development of the marine renewable energy (MRE) will impact traditional users of the marine resource, such as commercial fishermen. This could potentially lead to opposition and spatial conflict. The successful development of the MRE sector will heavily depend on the acceptance of projects by fishing communities. Effective stakeholder engagement is crucial to enhancing acceptance among fishermen. The consultation process is one of the key ways in which to engage fishermen and enable them to participate in decision-making. There is agreement among experts in the field that despite its importance, the consultation process is not effective and it is often carried out from the top down with little opportunity for real participation. A mixed methods research approach was used to examine the experiences of fishermen on their level of involvement in consultations and decision-making on marine renewable energy projects. In total, 104 surveys and 14 in-depth interviews were carried out with fishermen operating from ports at three case study sites around the island of Ireland where MRE projects were being developed. Just over half (56%) of those surveyed felt that they had been involved in consultations, while only 22% felt that they had been involved in decisions made on the projects. The use of participatory mapping tools in the selection of sites for MRE development provides an opportunity for fishermen to influence decisions. Designing and implementing marine spatial plans could also help to provide clarity and transparency over how trade-offs in the use of sea space are dealt with.

Are Wave and Tidal Energy Plants New Green Technologies?

Douziech M, Hellweg S, Verones F. Are Wave and Tidal Energy Plants New Green Technologies?. Environmental Science & Technology [Internet]. 2016 ;50(14):7870 - 7878. Available from: http://pubs.acs.org/doi/abs/10.1021/acs.est.6b00156
Freely available?: 
No
Summary available?: 
Yes
Type: Journal Article

Wave and tidal energy plants are upcoming, potentially green technologies. This study aims at quantifying their various potential environmental impacts. Three tidal stream devices, one tidal range plant and one wave energy harnessing device are analyzed over their entire life cycles, using the ReCiPe 2008 methodology at midpoint level. The impacts of the tidal range plant were on average 1.6 times higher than the ones of hydro-power plants (without considering natural land transformation). A similar ratio was found when comparing the results of the three tidal stream devices to offshore wind power plants (without considering water depletion). The wave energy harnessing device had on average 3.5 times higher impacts than offshore wind power. On the contrary, the considered plants have on average 8 (wave energy) to 20 (tidal stream), or even 115 times (tidal range) lower impact than electricity generated from coal power. Further, testing the sensitivity of the results highlighted the advantage of long lifetimes and small material requirements. Overall, this study supports the potential of wave and tidal energy plants as alternative green technologies. However, potential unknown effects, such as the impact of turbulence or noise on marine ecosystems, should be further explored in future research.

Life cycle assessment of ocean energy technologies

Uihlein A. Life cycle assessment of ocean energy technologies. The International Journal of Life Cycle Assessment [Internet]. 2016 ;21(10):1425 - 1437. Available from: http://link.springer.com/article/10.1007/s11367-016-1120-y
Freely available?: 
Yes
Summary available?: 
Yes
Type: Journal Article

Purpose

Oceans offer a vast amount of renewable energy. Tidal and wave energy devices are currently the most advanced conduits of ocean energy. To date, only a few life cycle assessments for ocean energy have been carried out for ocean energy. This study analyses ocean energy devices, including all technologies currently being proposed, in order to gain a better understanding of their environmental impacts and explore how they can contribute to a more sustainable energy supply.

Methods

The study followed the methodology of life cycle assessment including all life cycle steps from cradle to grave. The various types of device were assessed, on the basis of a functional unit of 1 kWh of electricity delivered to the grid. The impact categories investigated were based on the ILCD recommendations. The life cycle models were set up using detailed technical information on the components and structure of around 180 ocean energy devices from an in-house database.

Results and discussion

The design of ocean energy devices still varies considerably, and their weight ranges from 190 to 1270 t, depending on device type. Environmental impacts are closely linked to material inputs and are caused mainly by mooring and foundations and structural components, while impacts from assembly, installation and use are insignificant for all device types. Total greenhouse gas emissions of ocean energy devices range from about 15 to 105 g CO2-eq. kWh−1. Average global warming potential for all device types is 53 ± 29 g CO2-eq. kWh−1. The results of this study are comparable with those of other studies and confirm that the environmental impacts of ocean energy devices are comparable with those of other renewable technologies and can contribute to a more sustainable energy supply.

Conclusions

Ocean energy devices are still at an early stage of development compared with other renewable energy technologies. Their environmental impacts can be further reduced by technology improvements already being pursued by developers (e.g. increased efficiency and reliability). Future life cycle assessment studies should assess whole ocean energy arrays or ocean energy farms.

Environmental Impacts of the Deep-Water Oil and Gas Industry: A Review to Guide Management Strategies

Cordes EE, Jones DOB, Schlacher TA, Amon DJ, Bernardino AF, Brooke S, Carney R, DeLeo DM, Dunlop KM, Escobar-Briones EG, et al. Environmental Impacts of the Deep-Water Oil and Gas Industry: A Review to Guide Management Strategies. Frontiers in Environmental Science [Internet]. 2016 ;4. Available from: http://journal.frontiersin.org/article/10.3389/fenvs.2016.00058/full
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

The industrialization of the deep sea is expanding worldwide. Increasing oil and gas exploration activities in the absence of sufficient baseline data in deep-sea ecosystems has made environmental management challenging. Here, we review the types of activities that are associated with global offshore oil and gas development in water depths over 200 m, the typical impacts of these activities, some of the more extreme impacts of accidental oil and gas releases, and the current state of management in the major regions of offshore industrial activity including 18 exclusive economic zones. Direct impacts of infrastructure installation, including sediment resuspension and burial by seafloor anchors and pipelines, are typically restricted to a radius of ~100 m on from the installation on the seafloor. Discharges of water-based and low-toxicity oil-based drilling muds and produced water can extend over 2 km, while the ecological impacts at the population and community levels on the seafloor are most commonly on the order of 200–300 m from their source. These impacts may persist in the deep sea for many years and likely longer for its more fragile ecosystems, such as cold-water corals. This synthesis of information provides the basis for a series of recommendations for the management of offshore oil and gas development. An effective management strategy, aimed at minimizing risk of significant environmental harm, will typically encompass regulations of the activity itself (e.g., discharge practices, materials used), combined with spatial (e.g., avoidance rules and marine protected areas), and temporal measures (e.g., restricted activities during peak reproductive periods). Spatial management measures that encompass representatives of all of the regional deep-sea community types is important in this context. Implementation of these management strategies should consider minimum buffer zones to displace industrial activity beyond the range of typical impacts: at least 2 km from any discharge points and surface infrastructure and 200 m from seafloor infrastructure with no expected discharges. Although managing natural resources is, arguably, more challenging in deep-water environments, inclusion of these proven conservation tools contributes to robust environmental management strategies for oil and gas extraction in the deep sea.

Implementation and evaluation of the International Electrotechnical Commission specification for tidal stream energy resource assessment: A case study

Ramos V, Ringwood JV. Implementation and evaluation of the International Electrotechnical Commission specification for tidal stream energy resource assessment: A case study. Energy Conversion and Management [Internet]. 2016 ;127:66 - 79. Available from: http://www.sciencedirect.com/science/article/pii/S019689041630752X
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

Over the next decades, tidal stream energy aims to become a fully commercially viable energy source. For this purpose, complete knowledge regarding tidal stream resource assessment is essential. In this context, the International Electrotechnical Commission has developed a technical standard for the assessment of the tidal stream resource, “IEC 62600-201 TS: Marine energy - Wave, tidal and other water current converters - Part 201: Tidal energy resource assessment and characterisation”, offering a vast set of recommendations in the fields of data collection, numerical modelling, data analysis and reporting of the results with the purpose of standardising tidal stream resource characterisation. The standard divides resource assessments into two different classes: feasibility and layout design. The model setup procedure (mesh resolution, boundary conditions) and the computational effort required vary significantly from one class to another. For these reasons, the objective of the present work is to explore the proposed standard using the Orkney Region (N Scotland) as a case study. Overall, it was found that the standard works well, offering a detailed characterisation of the tidal resource; however, in order to improve its manageability, some aspects related to the grid resolution requirements and the approach to model a tidal energy converter could be revisited for future editions.

The importance of wave climate forecasting on the decision-making process for nearshore wave energy exploitation

López-Ruiz A, Bergillos RJ, Ortega-Sánchez M. The importance of wave climate forecasting on the decision-making process for nearshore wave energy exploitation. Applied Energy [Internet]. 2016 ;182:191 - 203. Available from: http://www.sciencedirect.com/science/article/pii/S0306261916311825
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

This work presents a new methodology for the medium to long-term stochastic forecasting of the main variables and indexes related to the wave climate that are involved in the decision-making process to allocate, operate and maintain individual nearshore wave energy converters (WECs) and/or wave farms. Compared to the state-of-the-art approaches, this methodology includes the assessment of the uncertainty by means of Monte Carlo simulations, constituting a valuable step forward. The methodology is based on the simulation of Ny-year time series of wave climate variables that maintain the same statistical descriptors and seasonal and year-to-years variations of a hindcasted time series. This step is repeated Ne times to provide a sample size large enough to assess the uncertainty of the predictions. Because the wave energy resource is obtained from the nearshore, a large amount of wave propagations would be required. However, our methodology incorporates downscaling techniques that significantly improve the computational efficiency, and only a reduced number of Nw sea states should be propagated using an advanced numerical model. The methodology was applied to Playa Granada beach (southern Spain), obtaining the wave energy resource at 24 locations in the nearshore for 25-year time series repeated 1000 times. The selection of the most promising location for WECs on the basis of hindcasted or forecasted data provides different results. This highlights the importance of the proposed methodology for the advanced planning and design of any prospective energy extraction project.

Avoidance of wind farms by harbour seals is limited to pile driving activities

Russell DJF, Hastie GD, Thompson D, Janik VM, Hammond PS, Scott-Hayward LAS, Matthiopoulos J, Jones EL, McConnell BJ. Avoidance of wind farms by harbour seals is limited to pile driving activities. Journal of Applied Ecology [Internet]. 2016 . Available from: http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12678/abstract
Freely available?: 
Yes
Summary available?: 
Yes
Type: Journal Article
  1. As part of global efforts to reduce dependence on carbon-based energy sources there has been a rapid increase in the installation of renewable energy devices. The installation and operation of these devices can result in conflicts with wildlife. In the marine environment, mammals may avoid wind farms that are under construction or operating. Such avoidance may lead to more time spent travelling or displacement from key habitats. A paucity of data on at-sea movements of marine mammals around wind farms limits our understanding of the nature of their potential impacts.
  2. Here, we present the results of a telemetry study on harbour seals Phoca vitulina in The Wash, south-east England, an area where wind farms are being constructed using impact pile driving. We investigated whether seals avoid wind farms during operation, construction in its entirety, or during piling activity. The study was carried out using historical telemetry data collected prior to any wind farm development and telemetry data collected in 2012 during the construction of one wind farm and the operation of another.
  3. Within an operational wind farm, there was a close-to-significant increase in seal usage compared to prior to wind farm development. However, the wind farm was at the edge of a large area of increased usage, so the presence of the wind farm was unlikely to be the cause.
  4. There was no significant displacement during construction as a whole. However, during piling, seal usage (abundance) was significantly reduced up to 25 km from the piling activity; within 25 km of the centre of the wind farm, there was a 19 to 83% (95% confidence intervals) decrease in usage compared to during breaks in piling, equating to a mean estimated displacement of 440 individuals. This amounts to significant displacement starting from predicted received levels of between 166 and 178 dB re 1 μPa(p-p). Displacement was limited to piling activity; within 2 h of cessation of pile driving, seals were distributed as per the non-piling scenario.
  5. Synthesis and applications. Our spatial and temporal quantification of avoidance of wind farms by harbour seals is critical to reduce uncertainty and increase robustness in environmental impact assessments of future developments. Specifically, the results will allow policymakers to produce industry guidance on the likelihood of displacement of seals in response to pile driving; the relationship between sound levels and avoidance rates; and the duration of any avoidance, thus allowing far more accurate environmental assessments to be carried out during the consenting process. Further, our results can be used to inform mitigation strategies in terms of both the sound levels likely to cause displacement and what temporal patterns of piling would minimize the magnitude of the energetic impacts of displacement.

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