Coastal and Offshore Energy

The impact of climate change on the levelised cost of wind energy

Hdidouan D, Staffell I. The impact of climate change on the levelised cost of wind energy. Renewable Energy [Internet]. 2017 ;101:575 - 592. Available from: http://www.sciencedirect.com/science/article/pii/S0960148116307856
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Society's dependence on weather systems has broadened to include electricity generation from wind turbines. Climate change is altering energy flows in the atmosphere, which will affect the economic potential of wind power. Changes to wind resources and their upstream impacts on the energy industry have received limited academic attention, despite their risks earning interest from investors.

We propose a framework for assessing the impact of climate change on the cost of wind energy, going from the change in hourly wind speed distributions from radiative forcing through to energy output and levelised cost of electricity (LCOE) from wind farms. The paper outlines the proof of concept for this framework, exploring the limitations of global climate models for assessing wind resources, and a novel Weibull transfer function to characterise the climate signal.

The framework is demonstrated by considering the UK's wind resources to 2100. Results are mixed: capacity factors increase in some regions and decrease in others, while the year-to-year variation generally increases. This highlights important financial and risk impacts which can be adopted into policy to enhance energy system resilience to the impacts of climate change. We call for greater emphasis to be placed on modelling wind resources in climate science.

Evaluation of the wave energy resources in the Cape Verde Islands

Bernardino M, Rusu L, C. Soares G. Evaluation of the wave energy resources in the Cape Verde Islands. Renewable Energy [Internet]. 2017 ;101:316 - 326. Available from: http://www.sciencedirect.com/science/article/pii/S0960148116307418
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

The Cape Verde Islands form an archipelago off the African coast in the Atlantic Ocean. Since it is highly dependent on fossil fuels, Cape Verde decision makers have started to take into account also the potential of renewable energies, especially wind and solar. In particular, wind power has already 26 MW installed. From this perspective, the present work aims to be a first step in the evaluation of a different source of renewable energy, the wave energy. Using reanalysis data from ECMWF, the SWAN model was run for a 10-year period, covering the time interval 2004–2013, using a methodology already implemented in other island environments. Moreover, three years of this high resolution data are compared with the available altimetry data. In this way, a dataset of the sea state conditions around Cape Verde Islands was produced. This dataset is further used for wave climate analyses and wave energy resource assessments. This study indicates that the coastal environment of the Cape Verde Islands, and especially some particular areas, present considerable wave energy resources that should be taken in consideration for extraction in the near future.

Renewable Energy In Situ Power Cable Observation

Love MS, Nishimoto MM, Clark S, Bull AS. Renewable Energy In Situ Power Cable Observation. Camarillo, CA: The U.S. Department of the Interior, Bureau of Ocean Energy Management, Pacific OCS Region; 2016 p. 86 pp. Available from: http://marinecadastre.gov/espis/#/search/study/26953
Freely available?: 
Yes
Summary available?: 
Yes
Type: Report

Specific objectives of this study were to determine:

  1. The differences among fish and invertebrate communities associated with energized and unenergized cable habitat and those communities in soft sea oor habitats lacking cables.
  2. Whether electrosensitive species that are regionally important such as sharks and rays respond (via either attraction or repulsion) to the EMF’s of an in situ power transmission cable.
  3. The strength, spatial extent, and variability of EMF’s along both energized and unenergized cables.
  4. The potential effectiveness of the commonly proposed mitigation of cable burial.

Knowledge gained from this study will be directly applicable to renewable energy projects not only in the Pacific OCS region, but to any OCS planning area. 

Effects of an Offshore Wind Farm (OWF) on the Common Shore Crab Carcinus maenas: Tagging Pilot Experiments in the Lillgrund Offshore Wind Farm (Sweden)

Langhamer O, Holand H, Rosenqvist G. Effects of an Offshore Wind Farm (OWF) on the Common Shore Crab Carcinus maenas: Tagging Pilot Experiments in the Lillgrund Offshore Wind Farm (Sweden). PLOS ONE [Internet]. 2016 ;11(10):e0165096. Available from: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0165096
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Worldwide growth of offshore renewable energy production will provide marine organisms with new hard substrate for colonization in terms of artificial reefs. The artificial reef effect is important when planning offshore installations since it can create habitat enhancement. Wind power is the most advanced technology within offshore renewable energy sources and there is an urgent need to study its impacts on the marine environment. To test the hypothesis that offshore wind power increases the abundance of reef species relative to a reference area, we conduct an experiment on the model species common shore crab (Carcinus maenas).Overall, 3962 crabs were captured, observed, marked and released in 2011 and 1995 crabs in 2012. Additionally, carapace size, sex distribution, color morphs and body condition was recorded from captured crabs. We observed very low recapture rates at all sites during both years which made evaluating differences in population sizes very difficult. However, we were able to estimate population densities from the capture record for all three sites. There was no obvious artificial reef effect in the Lillgrund wind farm, but a spill-over effect to nearby habitats cannot be excluded. We could not find any effect of the wind farm on either, morphs, sex distribution or condition of the common shore crab. Our study found no evidence that Lillgrund wind farm has a negative effect on populations of the common shore crab. This study provides the first quantitative and experimental data on the common shore crab in relation to offshore wind farms.

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.

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