Wave energy is arguably one of the most promising renewables. Less developed at present than other renewables, the existing models to estimate the costs of a wave energy project are often oversimplified, and the resulting scatter in the economic assessments weighs on the confidence of potential investors and constitutes therefore an impediment to the development of wave energy. Indeed, understanding the costs of wave energy is one of the main fields of research in marine renewable energy. In this context, the main objective of this paper is to review all the factors that must be considered in an economic analysis of wave energy, including a number of elements that are usually overlooked. In the process we characterise the direct and indirect costs of a wave farm – preliminary costs, construction, operation and maintenance and decommissioning cost – as well as its prospective incomes. For each of them a reference value is presented, together with a generic formula for its calculation. Moreover, the levelised cost, i.e., the production cost of an energy unit (1 kW h), is compared between various energy sources, and on these grounds conclusions on the profitability and competitiveness of wave energy are drawn. In sum, this work reviews the state of the art and sets the basis for a thorough economic analysis of wave energy.

The economics of wave energy: A review

One of the most abundant energy sources exists in this world is the ocean wave energy. By far, it has shown to be the most clean, renewable, predicted energy and has raised the potential to compete with the current use of non-renewable energy sources. Recent research conducted on wave energy invention has opened a new dimension to slowly reduce the dependency on fossil fuel by introducing new technology on the renewable world but relatively lacking in economical aspect. This review brings the latest status on integration of wave energy device with other marine facilities, which is the breakwater structure that may possibly aid to cost sharing. Most researches done on this field highlighted countries experiencing rough sea condition and focused less on countries with medium wave condition as faced by the Asian continent. The potential for energy extraction and wave dissipation for medium wave condition will be discussed in this review by considering several aspects including reliability, effectiveness and performance. Finally, this review shows that the integration opens up a new dimension to acknowledge the technology harnessing ocean wave, especially for the Asian countries experiencing medium wave condition.

Wave energy device and breakwater integration: A review

Variability Assessment and Forecasting of Renewables : A Review for Solar, Wind, Wave and Tidal Resources

Variability assessment and forecasting of renewables: A review for solar, wind, wave and tidal resources

Wave energy is substantial as a resource, and its potential to significantly contribute to the existing energy mix has been identified. However, the commercial utilization of wave energy is still very low. This paper reviewed the background of wave energy harvesting technology, its evolution, and the present status of the industry. By covering the theoretical formulations, wave resource characterization methods, hydrodynamics of wave interaction with the wave energy converter, and the power take-off and electrical systems, different challenges were identified and discussed. Solutions were suggested while discussing the challenges in order to increase awareness and investment in wave energy industry as a whole.

https://www.mdpi.com/1996-1073/11/5/1250/pdf

Ocean Wave Energy Converters: Status and Challenges

Ocean waves are a more predictable resource with a higher energy density compared to solar and wind. In addition, and specifically for the United States, resource locations with high wave power are close to major load centers being located along coastlines. These features have sparked a surge of attention in the United States on trying to economically harness ocean wave power. The aim of this article is to provide a concise review of the current state of ocean wave energy conversion technologies and industry status in the United States including research and development as well as commercial activities and governmental support, concluding with a discussion of future industry perspectives. Existing facilities, softwares as well as laboratory and open-water test facilities and resources, active research groups and commercial activities have been identified. Over one third of commercially active wave energy developers worldwide are located within the United States, but only a few have reached a high Technology Readiness Level. These findings, together with a relevant practical resource located within the U.S. and the advantageous nature of the resource compared to other renewable resources, indicate that the United States is well positioned to advance the wave energy industry in the near future.

Ocean wave energy in the United States: Current status and future perspectives

The substantial wave energy resource of the US Pacific Northwest (i.e. off the coasts of Washington, Oregon and N. California) is assessed and characterized. Archived spectral records from ten wave measurement buoys operated and maintained by the National Data Buoy Center and the Coastal Data Information Program form the basis of this investigation. Because an ocean wave energy converter must reliably convert the energetic resource and survive operational risks, a comprehensive characterization of the expected range of sea states is essential. Six quantities were calculated to characterize each hourly sea state: omnidirectional wave power, significant wave height, energy period, spectral width, direction of the maximum directionally resolved wave power and directionality coefficient. The temporal variability of these characteristic quantities is depicted at different scales and is seen to be considerable. The mean wave power during the winter months was found to be up to 7 times that of the summer mean. Winter energy flux also tends to have a longer energy period, a narrower spectral width, and a reduced directional spread, when compared to summer months. Locations closer to shore, where the mean water depth is less than 50 m, tended to exhibit lower omnidirectional wave power, but were more uniform directionally. Cumulative distributions of both occurrence and contribution to total energy are presented, over each of the six quantities characterizing the resource. It is clear that the sea states occurring most often are not necessarily those that contribute most to the total incident wave energy. The sea states with the greatest contribution to energy have significant wave heights between 2 and 5 m and energy periods between 8 and 12 s. Sea states with the greatest significant wave heights (e.g.>7 m) contribute little to the annual energy, but are critically important when considering reliability and survivability of ocean wave energy converters.

/pdf/the-wave-energy-resource-of-the-us-pacific-northwest-1guyubzmvm.pdf

The wave energy resource of the US Pacific Northwest

Characterizing the wave energy resource of the US Pacific Northwest

This paper was presented at the 9th European Wave and Tidal Energy Conference held in Southampton, UK September 4-11, 2011.

/pdf/laboratory-observation-of-waves-in-the-vicinity-of-wec-4ph9862igv.pdf

Laboratory Observation of Waves in the Vicinity of WEC-Arrays

An apparatus and method for converting wave energy using the relative rotational movement between two interconnected float assemblies and the relative rotational movement between each of the float assemblies and a spar which extends from a buoyant nacelle having a central longitudinal axis wherein the floats are nestable behind the buoyant nacelle.

Method and system for wave energy conversion

Knowledge of the effects of wave energy converters (WECs) on the near and far wave fields is critical to the efficient and low-risk design of waveforms. Several computational wave models enable the evaluation of WEC array effects, but model validation has been limited. In this chapter, we validate two popular models with very different formulations: the phase-resolving model WAMIT and the phase-averaged Simulating WAves Nearshore (SWAN) model. The models are validated against wave data from an extensive set of WEC array laboratory experiments conducted by Oregon State University and Columbia Power Technologies, Inc (CPT). The experimental WECs were 1:33 scale versions of a commercial device (CPT “Manta”), and several different WEC array configurations were subjected to a range of regular waves and random sea states. The wave field in the lee of the WEC arrays was mapped, and the wave shadow was quantified for all sea states. In addition, the WEC power capture performance was measured independently via a motion-tracking system and compared to the observed wave energy deficit (i.e., the wave shadow). Overall, WAMIT displays skill in predicting the wave field both in offshore and in the lee of the WEC arrays. WAMIT simulations demonstrate partial standing wave patterns that are consistent with the observations. These patterns are related to wave scattering processes, and their presence increases the magnitude of the wave shadow in the lee of WECs . The pattern is less pronounced at longer wave periods where WECs behave more like wave followers. In these situations, the wave shadow is primarily controlled by the WEC energy capture and less so by scattering. The SWAN model accounts for the frequency-dependent energy capture of the devices and performs well for cases when the wave shadow is primarily controlled by the WEC energy capture. For regular wave cases, inclusion of the wave diffraction process is necessary, but SWAN simulations for wave fields with frequency and directional spreading capture the general character of the wave shadow even without diffraction. Finally, we suggest that WECs designed to operate such that the expected significant wave energy lies at periods near, or larger than, the period of peak energy extraction will minimize the wave shadow effect for a given gross extraction of wave energy, which leads to more efficient arrays with respect to environmental impact.

Pukha Lenee-Bluhm

Papers

The wave energy resource of the US Pacific Northwest

Characterizing the wave energy resource of the US Pacific Northwest

Laboratory Observation of Waves in the Vicinity of WEC-Arrays

Method and system for wave energy conversion

Analyses of Wave Scattering and Absorption Produced by WEC Arrays: Physical/Numerical Experiments and Model Assessment