Technologising the wave

2020 ◽  
Vol 3 (1) ◽  
pp. 101-122
Author(s):  
Marfuga Iskandarova ◽  
Elena Simakova ◽  

Despite the recent shift from renewable energy to a low carbon policy, the UK policy discourse still recognises marine energy as part of the country’s future energy mix. Production of what we call an “assemblage” of technology and ocean waves triggers complex sets of initiatives that provide the basis for the economic viability and credibility of wave energy extraction. However, questions are rarely asked about how the natural phenomenon being part of this assemblage is construed as a resource to become a key element of promises and assessments of potential of renewable energy. This study sheds light on under-explored aspects of the credibility–economy and valuation practices formed around renewable energy that have not yet been problematised in social studies of energy. Arguing that ocean waves become an energy resource largely through resource assessment practices, we examine such practices in the context of the production of scientific and policy discourses around wave energy. Considering waves as an object of expertise, we examine how “wave data” constituted through measurements, statistical analysis, modelling and visualisation, contribute to the assessment and legitimisation of wave energy developments. We also evaluate the prospects for wave energy to be a “good” in future economic exchange.

Author(s):  
M. T. Pontes ◽  
M. Bruck

The conversion of the energy contained in ocean waves into an useful form of energy namely electrical energy requires the knowledge at least of wave height and period parameters. Since 1992 at least one altimeter has been accurately measuring significant wave height Hs. To derive wave period parameters namely zero-crossing period Tz from the altimeter backscatter coefficient various models have been proposed. Another space-borne sensor that measures ocean waves is SAR (or the advanced ASAR) from which directional spectra are obtained. In this paper various models proposed to compute Tz from altimeter data are presented and verified against a collocated set of Jason altimeter and NDBC buoy data. A good fitting of altimeter estimates to buoy data was found. Directional spectra obtained from ENVISAT ASAR measurements were compared against NDBC buoy data. It was concluded that for the buoys that are more sensitive to long low-frequency wave components the fitting of wave parameters and spectral form is good for short spatial distances. However, since the cut-off ASAR frequency is low (reliable information is provided only for long waves) their use for wave energy resource assessment in areas where wind-waves are important is limited.


Author(s):  
Brendan Cahill

Harnessing the power of ocean waves offers enormous potential as a source of renewable energy. To date the technologies for capturing this resource, collectively known as wave energy converters (WECs), have yet to reach commercial viability and continued research and development efforts are required to move wave energy to the industrial scale. Integral to this process is ensuring that technologies progress along a staged development pathway; proving WEC concepts using small scale physical models in controlled settings such as laboratory wave tanks before eventually advancing to testing sub-prototype and full scale devices in real sea conditions. The primary objective of this research is to improve the understanding of how best to address the scaling of wave resource measurements and wave energy device power production when analyzing the results of sea-trials. This paper draws on measured data from three test sites; Galway Bay in Ireland, the Pacific Marine Energy Test Centre off the coast of Oregon, and Lake Washington, and assesses how accurately they recreate, at reduced scale, the conditions that commercial WEC installations are likely to encounter at exposed deployment locations. Appropriate techniques for extrapolating these results to predict the performance of commercial WECs at energy-rich locations on the west coasts of Ireland and the US are also demonstrated and discussed. The output from this research will be a set of protocols for addressing wave energy resource scalability to help guide device developers through this important stage of technology progression. Improved knowledge regarding resource scalability will allow for more streamlined progression of WEC concepts from wave tanks to sea-trials, and eventually to full-scale ocean deployment. It will also result in a reduced uncertainty about device power output and survivability, which are key drivers in determining the economic viability of projects.


2002 ◽  
Vol 36 (4) ◽  
pp. 42-51 ◽  
Author(s):  
M. T. Pontes ◽  
L. Cavaleri ◽  
Denis Mollison

The aim of this paper is to provide a general view of wave energy resource assessment. First, a review of the origin of waves and the transformation they undergo as they propagate towards the coast through waters of decreasing depth is presented. Following this, the wave and wave-energy parameters and the statistics required for resource characterization are described. The various types of wave data and their usefulness for the present purposes are summarised. A common methodology for assessment of the wave energy resource is developed. Finally, a general description of the global open ocean resource is presented.


2021 ◽  
Vol 13 (11) ◽  
pp. 2070
Author(s):  
Ana Basañez ◽  
Vicente Pérez-Muñuzuri

Wave energy resource assessment is crucial for the development of the marine renewable industry. High-frequency radars (HF radars) have been demonstrated to be a useful wave measuring tool. Therefore, in this work, we evaluated the accuracy of two CODAR Seasonde HF radars for describing the wave energy resource of two offshore areas in the west Galician coast, Spain (Vilán and Silleiro capes). The resulting wave characterization was used to estimate the electricity production of two wave energy converters. Results were validated against wave data from two buoys and two numerical models (SIMAR, (Marine Simulation) and WaveWatch III). The statistical validation revealed that the radar of Silleiro cape significantly overestimates the wave power, mainly due to a large overestimation of the wave energy period. The effect of the radars’ data loss during low wave energy periods on the mean wave energy is partially compensated with the overestimation of wave height and energy period. The theoretical electrical energy production of the wave energy converters was also affected by these differences. Energy period estimation was found to be highly conditioned to the unimodal interpretation of the wave spectrum, and it is expected that new releases of the radar software will be able to characterize different sea states independently.


2013 ◽  
Vol 55 ◽  
pp. 480-489 ◽  
Author(s):  
J.P. Sierra ◽  
D. González-Marco ◽  
J. Sospedra ◽  
X. Gironella ◽  
C. Mösso ◽  
...  

Author(s):  
Ed Mackay ◽  
AbuBakr Bahaj ◽  
Chris Retzler ◽  
Peter Challenor

The use of altimeter measurements of significant wave height and energy period for quantifying wave energy resource is investigated. A new algorithm for calculating wave period from altimeter data, developed by the authors in previous work, is used to estimate the power generated by the Pelamis wave energy converter and compared to estimates from collocated buoy data. In offshore locations accurate estimates of monthly and annual mean power can be achieved by combining measurements from six altimeter missions. Furthermore, by averaging along sections of the altimeter ground track, we demonstrate that it is possible to gauge the spatial variability in nearshore areas, with a resolution of the order of 10 km. Although measurements along individual tracks are temporally sparse, with TOPEX/Poseidon and Jason on a 10 day repeat orbit, GFO 17 days, and ERS-2 and ENVISAT 35 days, the long record of altimeter measurements means that multi-year mean power from single tracks are of a useful accuracy.


2020 ◽  
Vol 8 (4) ◽  
pp. 253 ◽  
Author(s):  
Yapo Wang ◽  
Lixian Zhang ◽  
Constantine Michailides ◽  
Ling Wan ◽  
Wei Shi

Due to the energy crisis and greenhouse effect, offshore renewable energy is attracting increasing attention worldwide. Various offshore renewable energy systems, such as floating offshore wind turbines (FOWTs), and wave energy converters (WECs), have been proposed and developed so far. To increase power output and reduce related costs, a combined marine energy structure using FOWT and WEC technologies has been designed, analyzed and presented in the present paper. The energy structure combines a 5-MW braceless semisubmersible FOWT and a heave-type WEC which is installed on the central column of the semisubmersible. Wave power is absorbed by a power take-off (PTO) system through the relative heave motion between the central column of the FOWT and the WEC. A numerical model has been developed and is used to determine rational size and draft of the combined structure. The effects of different PTO system parameters on the hydrodynamic performance and wave energy production of the WEC under typical wave conditions are investigated and a preliminary best value for the PTO’s damping coefficient is obtained. Additionally, the effects of viscous modeling used during the analysis and the hydrodynamic coupling on the response of the combined structure are studied.


Author(s):  
Alain Ulazia ◽  
Aitor Urresti ◽  
Alvaro Campos ◽  
Gabriel Ibarra-Berastegi ◽  
Mirari Antxustegi ◽  
...  

The students of the Faculties of Engineering of the Universitty of Basque Country (Gipuzkoa-Eibar and Bilbao) in the last years of their studies, before becoming engineers, have the opportunity to select a block of subjects intended to enhance their knowledge on renewable energy systems. One of these subjects is Solar Thermal and Geothermal energy. These subjects are devoted to assessing the renewable energy resource, and designing optimal systems. Apart from the transmission of good practices, the focus is practical and is based on hands-on computer real-life exercises, which involves not only intensive programming using high-level software, but also the spatial representation of results. To that purpose two main open source codes are used: Octave (https://www.gnu.org/software/octave/), and QGIS (https://www.qgis.org/). Students learn how to address real-life problems regarding the geographical representation of solar radiation and low temperature geothermal resources using QGIS, and solar thermal system modelling using Octave.


2015 ◽  
Vol 42 (13) ◽  
pp. 5452-5459 ◽  
Author(s):  
Lonneke Goddijn-Murphy ◽  
Belén Martín Míguez ◽  
Jason McIlvenny ◽  
Philippe Gleizon

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