Environmental Engineering Reference
In-Depth Information
In principle, the physical characteristics of wind power plants are similar to those
of ocean current plants. The main difference is that, because water has a higher
density than air, ocean current plants can achieve higher output yields than wind
power plants even when the speed of currents is low.
Ocean current plants are limited to regions with relatively consistent high current
speeds and moderate water depths of up to 25 m. These conditions mainly exist on
headlands and bays, between islands and in straits. Although shipping lanes often
restrict this kind of use, major potential exists. As technological advances and the
benefi ts of mass production are rapidly leading to cost reductions, in the medium
term ocean current power plants could become another building block in the genera-
tion of a climate-compatible electricity supply.
9.4 Planning and Design
All types of hydropower plants require different and sometimes complex planning
and design. It is only possible here to outline some of the basic planning aspects.
The fi rst requirement for a run-of-river power plant is the collection of information
about the stretch of water where the plant is to be built. The most important param-
eter is the runoff of the river's water over the course of a year - that is, the volume
of water that fl ows through the river. Each river has its own typical annual fl ow
characteristic that is infl uenced mainly by rain and melting snow. For further design
purposes, the river runoff volumes are sorted to obtain an annual continuous curve.
This indicates the number of days per year on which a river achieves or exceeds a
certain runoff volume (Figure 9.15).
2500
2500
2000
2000
1500
1500
not
usable
1000
1000
rated runoff
part load
500
500
usable
water
0
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0
30
60
90 120 150 180 210 240 270 300 330 360
days per year
Figure 9.15
Annual fl ow characteristics and annual continuous curve for the Rhine runoff near
Rheinfelden.
