Comparison of Wave Energy and Offshore Wind

Author(s):  
Laura Castro-Santos ◽  
Félix Puime Guillén
Keyword(s):  
Author(s):  
Weixing Chen ◽  
Feng Gao

Energy resources of offshore wind and ocean wave are clean, renewable and abundant. Various technologies have been developed to utilize the two kinds of energy separately. This paper presents the principle of an integrated generation unit for offshore wind power and ocean wave energy. The principle of the unit includes that: The wind rotor with retractable blades and the 3-DOF (degrees of freedom) mechanism with the hemispherical oscillating body are used to collect the irregular wind and wave power, respectively; The energy conversion devices (ECDs) are utilized to convert mechanical energy from both the wind rotor and the 3-DOF mechanism into hydraulic energy; The hydraulic energy is used to drive the hydraulic motors and electrical generators to produce electricity. Some analyses and experiments of the unit is conducted.


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.


2020 ◽  
Vol 162 ◽  
pp. 103731 ◽  
Author(s):  
Yu Zhou ◽  
Dezhi Ning ◽  
Wei Shi ◽  
Lars Johanning ◽  
Dongfang Liang

Author(s):  
Sharay Astariz ◽  
Gregorio Iglesias

If marine energy is to become a viable alternative to fossil fuels, its competitiveness must be enhanced. In this sense, combining various renewables in the same marine space is emerging as a solution. Among the different options, this paper focuses on combined wind and wave energy farms. First, the different synergies between both renewable are analysed, such as the more sustainable use of the marine resource or the opportunity to reduce costs of both technologies by sharing some of the most important costs of an offshore project. Second, this paper focuses on two technology synergies: the reduction of the inherent intermittency of renewables; and the so-called shadow effect which implies the reduction of the wave height in the inner part of the wind farm. Both effects may suppose an important reduction in the operation and maintenance cost by reducing the balancing cost when connecting the installation to the grid and increasing weather windows to access the wind turbines. However, the benefits of this combination will depend on the site characteristics and the array layout. On this basis, the power smoothing and shadow effect in co-located farms are analysed through different case studies considering real sea conditions, wind farms currently in operation and a high resolution numerical model (SWAN). Finally, conclusions about the economic benefits of co-located farms are drawn by recalculating the levelised cost of energy when both renewable are combined.


2015 ◽  
Vol 628 ◽  
pp. 012117 ◽  
Author(s):  
Deirdre O'Donnell ◽  
Bruno Srbinovsky ◽  
Jimmy Murphy ◽  
Emanuel Popovici ◽  
Vikram Pakrashi

Author(s):  
Lin Li ◽  
Zhen Gao ◽  
Torgeir Moan

The design of wind turbines requires information about joint data for wind and wave conditions. Moreover, combining offshore wind and wave energy facilities is a potential way to reduce the cost of offshore wind farms. To design combined offshore renewable energy concepts, it is important to choose sites where both wind and wave energy resources are substantial. This paper deals with joint environmental data for five European offshore sites which serve as basis for the analysis and comparison of combined renewable energy concepts developed in the EU FP7 project—MARINA Platform. The five sites cover both shallow and deep water, with three sites facing the Atlantic Ocean and two sites in the North Sea. The long-term joint distributions of wind and wave parameters are presented for these sites. Simultaneous hourly mean wind and wave hindcast data from 2001 to 2010 are used as a database. The joint distributions are modeled by fitting analytical distributions to the hindcast data. 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. The marginal distributions of wind and wave parameters 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.


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