Environmental Engineering Reference
In-Depth Information
0.6
0.4
0.2
0
0
0.2
0.4
Effectiveness
Figure 7.23
The turbine capacity factor
η
as a function of power plant effectiveness
for single effect tidal
power plants. (Data from Fay, J., and M. Smachlo, 1983.
J. Energy,
7
, 529.)
Tidal Power Plant Characteristics
a
TABLE 7.6
Site Location
Annapolis Royal
La Rance
Pool area
A
(km
2
)
4.8
12.9
Tidal range
H
(m)
6.3
8.5
Rated turbine flow rate (m
3
/s)
378
3240
Rated turbine head (m)
5.5
8
Rated electric power (MW)
17.8
240
Sluice gate flow area (m
2
)
230
1530
Capacity factor,
η
0.321
0.225
Effectiveness,
0.171
0.331
a
Data from Fay, J., and M. Smachlo, 1983.
J. Energy,
7
, 529.
,
the ratio of the average turbine power output to the rated turbine output. A high capacity factor
provides more annual revenue per unit of capital investment in the turbine/generator. A second
measure is the plant
effectiveness
There are two measures of performance of a tidal power plant. One is the
capacity factor
η
, the ratio of the average power output to the ideal power of
equation (7.17). A high effectiveness allows the plant to utilize most of the tidal power available
at the site. Unfortunately, it is not possible to obtain high values for both these measures simulta-
neously, because increasing one causes the other to decrease. Figure 7.23 shows the relationship
of these parameters for single effect plants.
25
The characteristics of two plants that are currently in operation are listed in Table 7.6. The
smaller plant, at Annapolis Royal (Figure 7.24), has a higher capacity factor but lower effectiveness
than the larger one at La Rance, in agreement with the trends of Figure 7.23. The average electrical
power outputs per square kilometer of tidal pool area are 1.19 MW/km
2
and 4.19 MW/km
2
,
respectively, for the Annapolis Royal and La Rance plants.
25
For the cycle shown in Figure 7.22,
η
=
0
.
4 and
=
0
.
25.
