OCEAN, WIND AND WAVE ENERGY UTILIZATION (original) (raw)
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Committee V.4: Offshore Renewable Energy
Day 1 Sun, September 11, 2022
Committee Mandate Concern for load analysis and structural design of offshore renewable energy devices. Attention shall be given to the interaction between the load and structural response of fixed and floating installations taking due consideration of the stochastic and extreme nature of the ocean environment. Aspects related to design, prototype testing, certification, marine operations, levelized cost of energy and life cycle management shall be considered. Introduction This is the sixth time that ISSC has included the Specialist Committee V.4 Offshore Renewable Energy, which started in 2006. Two members of the committee for this term (2018-2022) were involved in the work for the previous term (2016-2018), which formulates a good base for the cooperative work in the last three years. The mandate of the committee was discussed at the beginning of the work, and it was slightly modified to include extreme environmental conditions and interaction of structures to the seabed, reliabil...
The costs for an offshore wind farm, especially with bottom fixed foundations increase significantly with increasing water depth. If costs can be reduced to a competitive level, the potential for wind farms in deep water is huge. One way of reducing costs might be to combine offshore wind with wave energy facilities at sites where these resources are concentrated. In order to design combined renewable energy concepts, it is important to choose sites where both wind and wave energy resources are substantial. Such facilities might be designed in ultimate limit states based on load effects corresponding to 50year wind and wave conditions. This requires a long-term joint probabilistic model for the wind and wave parameters at potential sites. In this paper, five European offshore sites are selected for analysis and comparison of combined renewable energy concepts developed in the EU FP7 project-MARINA Platform. The five sites cover both shallow water (<100m) and deep water (>200m), with three sites facing the Atlantic Ocean and the other two sites in the North Sea. The selection of the sites is carried out by considering average wind and wave energy resources, as well as extreme environmental conditions which indicate the cost of the system. Long-term joint distributions of mean wind speed at 10meter height (U w), significant wave height (H s) and spectral peak period (T p) are presented for selected sites. Simultaneous hourly wind and wave hindcast data from 2001-2010 are used as a database, which are obtained from the National and Kapodistrian University of Athens. The joint distributions are estimated by fitting analytical distributions to the hindcast data following a procedure suggested by Johannessen et al. (2001). The long-term joint distributions can be used to estimate the wind and wave power output from each combined concept, and to estimate the fatigue lifetime of the structure. For estimation of the wind and wave power separately, the marginal distributions of wind and wave are also provided. Based on the joint distributions, contour surfaces are established for combined wind and wave parameters for which the probability of exceedance corresponds to a return period of 50 years. The design points on the 50-year contour surfaces are suggested for extreme response analysis of combined concepts. The analytical long-term distributions established could also be applied for design analysis of other offshore structures with similar environmental considerations of these sites.
Marine renewable technologies (wind, wave and tidal) have undergone significant research and development in recent years. Offshore wind is now an established industry, tidal energy is on the verge of becoming commercial whilst wave energy is still an emerging industry. The combination of wind and wave devices on single platforms may have the potential to make these renewable energy solutions more economically competitive. However, the structural design implications of such combinations have not to date been investigated in detail. This paper considers a combination of an offshore wind turbine with a monopole foundation and a point absorber wave energy device. Two site locations, on the east and the south west coast of Ireland, with widely varying resource levels and extreme conditions are used in the analysis. Ten years of simulated data from the two sites enabled the accurate assessment of site conditions. The effects of site choice on the design are investigated by comparing the steel tonnages for east coast and west coast solutions. The analysis emphasizes the importance of site choice for combined wind and wave device solutions. It also forms the basis of understanding the economic implications for combined wind-wave farms and the related impact on the cost of energy. The comparisons are also helpful in assessing the feasibility of concepts from a structural point of view before considering detailed testing or site deployment.
Planning and Development of Ocean Wave Energy Conversion
At the beginning of the 21st century, global environmental problems, including global warming, were attracting attention worldwide. In these circumstances, momentum is building across the world for the effective utilization of clean and renewable natural energy sources. The ocean is the world's largest collector and storage medium for solar energy. At the same time, it produces various forms of energy while interacting with the atmosphere. Wave energy is an indirect and condensed form of solar energy. Wave gathers their energy from the wind. Wave gather, store and transmit this energy thousands of kilometers with little loss. As long as sun shines, wave energy will never be depleted. It varies in intensity, but it is available throughout the day and year.
Comparison of Wave Energy and Offshore Wind
Econometrics of Green Energy Handbook, 2020
The aim of this chapter is to compare wave energy and offshore wind energy in economic terms. The future of energy and electricity production will be at ocean. In this sense, offshore wind and wave energy are the two main important offshore renewable energies. However, it is important to compare them in economic terms to calculate their feasibility in order to take strategic decisions. In this context, aspects such as the LCOE are calculated to provide an economic comparison of these two technologies. The methodology will be carried out for a particular case of study. The location selected for this purpose has the offshore wind resource, and the wave energy resource is very good: It is the region of Galicia (located in the northwest of Spain). Results indicate the best ocean renewable energy in economic terms. This comparison is useful for future considerations in order to select the best location for an offshore renewable energy farm.
Idealized design parameters of Wave Energy Converters in a range of ocean wave climates
International Journal of Marine Energy, 2017
The effect of the idealized design parameters, the natural period of oscillation and damping, on the performance of a generic Wave Energy Converter (WEC) model is investigated. Other studies have been conducted on specific WEC technologies, overlooking the impact of these design parameters. Australia has been used as a case study. The consequences of the damping parameter are highlighted. A broad range of ocean wave climates are investigated across different seasons to determine the idealized values of the parameters appropriate for a location, to assist planning for extensive WEC deployments. Swell and wind-sea wave systems were studied; the response of generic model was used to determine the theoretical power generated. It was found that WECs should be selected for a location based on their damping as well as their natural period of oscillation so that the ocean wave resource is optimally utilised.