TIDAL POWER-MOVING AHEAD - Energy Research Developments: Tidal Energy, Energy Efficiency and Solar Energy - page 101

In parallel, Renetec, a Korean renewables development company, have agreed a joint
venture with Voith Siemens Hydro for a 600MW 'Seaturtle' tidal current turbine project in the
South Korean province of Wando. This has a rotor mounted in a vertical frame on a moveable
horizontal bar.
While the UK dominates in Europe , Norway has also been very active. A large propeller-
type device, fixed to the sea-bed, has been tested at Kvalsund, and Hammerfest Strom and
Statoil have plans for a full scale unit. In addition, a large novel floating 'Morild' multi-rotor
tidal project is being developed by Hydra Tidal with support from Statkraft.
In France, Hydrohelix Energies have a 10kW demonstration ducted-rotor sea-bed
mounted project, and plans for a 1MW Marenegie programme in Brittany, while a German
company, Atlantis Strom, has developed a novel sea bed mounted horizontal axis rotor. In the
Netherlands, tests have been underway on the two bladed Tocardo turbine.
The EU backed Enemar project in Italy has led to test with a novel vertical-axis Kobald
turbine in the straits of Messina, between Sicily and mainland Italy. Interests has been shown
in this system by China, which is looking at possible project in the Straits of Jintang in the
Zhoushan Archipelaga.
Finally, Russia has also continued its involvement with tidal power, via experiments in
the Arkhangelsk region with a 1.5MW turbine developed by Hydro WGC and mounted in a
floating pontoon.
The Prospects for Tidal Power
Tidal energy is now becoming recognised as a major potential renewable energy source.
It has been estimated that, if all the potential tidal barrages sites around the world were
developed, they might supply around 300TWh p.a (Elliott 2004). Location is clearly a crucial
issue, in terms of both access to the energy resource and links to power grids. Fortunately,
the areas around most large estuaries in the industrial world are relatively highly populated,
so there are major potential loads nearby and less need to provide major new gird links over
long distances.
In some cases tidal lagoons might be more appropriate as an alternative to barrages, but
in others they might be seen as additional options. For example it has been estimated that the
UK might expect to obtain up to 8% of its power from lagoons, in addition to around 15%
from barrages, although in some locations, e.g. in the Severn estuary, depending on the siting,
there could conflicts between them.
As noted above, given the lunar cycles, large barrages and lagoons would at times deliver
large bursts of electricity, which, in the absence of major energy storage facilities, may not be
well matched to local or national demand patterns. Clearly if there were several barrages
and/or lagoons around the coast, all feeding into the grid network, then their aggregate output
would be somewhat more continuous, given the different phasing of the tides around the
coast. So the system would provide outputs of higher value. However, this benefit could be
much more marked if large numbers of tidal current turbines, sited in wider range of
locations, were linked to the grid (Sinden 2005).
Suitable locations for tidal current projects may be somewhat less accessible than for
barrages and lagoons. Flow rates of around 5m/s are seen as necessary, and these usually
only occur in areas where there are natural constrictions in the coastal topography, and these