TABLE 1 Definitions Used by Department of Energy Marine and Hydrokinetic Resource Assessment Groups and National Research Council (NRC) Committee

Term to be Quantified Definition Units Notes
       
Energy The capacity to do work Joules (J)  
Power Energy per time Watts (W) = joules per second  
Resource Average annual power Terawatt-hours (TWh) per year (1 TWh/yr = 114 megawatts [MW]) Representing a potential energy resource base for the electricity sector in terawatt-hours.
Waves      
Wave power density (Mei, 1989) Power of waves per unit crest length based on
Pvector = pg Σ S(f,θ)cg df
Watts per meter Horizontal energy flux (power density); applies to a single device.
Wave power density (Electric Power Research Institute [EPRI]) Power of waves per unit circle based on
Pscalar = pg ΣΣ S(f,θ)cg df dθ
Watts per meter Horizontal energy flux; applies to a single device.
Total regional wave resource (EPRI) Based on annual average sum of wave power density along a line defining a region of coastline, such as a bathymetric contour.
Pcoast = Σ Pscalar dl
Terawatt-hours per year (= 114 MW) Overestimates the total resource by including energy flux along the line.
Total regional wave resource (recommended by this committee) Based on annual average sum of wave power density crossing perpendicular to a line defining a region of coastline, such as a bathymetric contour.
Pcoast = Σ Pvector cosθ dl
Terawatt-hours per year (= 114 MW) Remains approximately constant as waves travel shoreward from deep water.


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