Page 296 - Renewable Energy Devices and System with Simulations in MATLAB and ANSYS

Marine and Hydrokinetic Power Generation and Power Plants 283

Energy period, Te [sec]
4.5 5.5 6.5 7.5 8.5 9.5 10.5 11.5 12.5 13.5 14.5 15.5 16.5 17.5
0.75 14 5 22 10 11 13 14 15 14 13 12 10 10 36 8 12 7
8
37
31
24
26
37
Significant wave height, Hs [m] 2.25 119 102 124 146 114 113 113 107 137 127 108 100 110 108
1.25
31
38
20
33
27
37
61
42
61
1.75
52
68
28
57
71
44
21
71
48
70
96
70
75
45
32
84
57
99
89
69
164
66
82
162
152
2.75
167
46
218
171
204
224
230
202
185
91
140
172
145
64
3.25
135
188
264
175
292
301
3.75
142
85
222
183
226
282
239
266
353
331
219
179
367
151
299
337
278
380
287
232
4.25
235
4.75
165
437
343
483
405
262
320
518
429
503
563
5.25
224
344
541
477
5.75 186 286 355 416 468 451 432 404 365 339 287 267 218 135
408
265
610
377
309
199
404
569
510
639
597
666
515
5.2 6.4 7.5 8.7 9.9 11.0 12.2 13.3 14.5 15.7 16.8 18.0 19.1 20.3
Peak period, Tp [sec]
FIGURE 11.16 Mechanical power matrix for a two-body floating-point absorber.
resulting mechanical power matrix for the two-body floating-point absorber system from numerical
simulations.
To estimate the electrical power matrix, in which the maximum power output was also limited to the
rated power (also referred to as capacity), the mechanical power matrix is multiplied with a mechanical-
to-electrical conversion efficiency. The electrical power at each binned sea state is calculated from
 P m × η 1 , P m × η 1 < P rated

P e =  ≥ (11.4)
  P rated , P m × η 1 P rated
where
P m and P e are the predicted mechanical and electrical power that can be generated for each binned
sea state
P rated is the rated power
η 1 is the power take-off (PTO) efficiency that accounts for the losses between the absorbed mechani-
cal power and the electrical power output
The rated power was calculated from
P rated = P ae (11.5)
C f
where
C f is the capacity factor
P ae is the annual averaged electrical power, which was obtained by summing the product of the elec-
trical power matrix and the joint probability distribution for the reference site
Note that the annual averaged electrical power output increases and the capacity factor decreases as
the rated power for the generator is increased, as shown in Figure 11.17. However, it costs more for a
generator with larger capacity. Finally, the estimated annual energy production (AEP) (in megawatt-
hours), which typically also includes the transmission losses and maintenance-related losses, can be
calculated by
×
AEP = P e 8776 h () ×β (11.6)
where β =η η is the parameter, accounting for the losses caused by device availability and the transmis-
23
sion efficiency.