Environmental Engineering Reference
In-Depth Information
Figure 4.60.
Aerial view of the tidal barrage and 240-megawatt tidal power station at
the estuary of the River Rance at Saint Malo, France.
Source:
Tswgb at Wikimedia
Commons.
The biggest problem with such plants is that they interfere with the movement of ships
and marine animals and disturb delicate estuarine environments. However, recent advances
allow tidal plants to be located far from estuaries, offering greater flexibility in terms of
capacity and impact.
Under certain conditions the kinetic energy of tidal or ocean currents may be harnessed
withoutabarrageusingturbinesthatexploittidaloroceancurrents.Thedifferencebetween
these is that tidal currents change direction between ebb and flow cycles, while ocean
currents have a unidirectional flow. Tidal and ocean current turbines are very similar;
the main difference being that tidal installations have been designed to operate in both
directions. The turbine has a horizontal axis and more closely resembles turbines than to
hydro turbines (see
Figure 4.61
)
(Lewis et al.
2011
)
.
