An announcement was made during
late February in Bermuda advising that construction was to begin
on an undersea windmill installation that will provide up to 10%
of Bermuda's electricity. This project will be the first
commercial application of a technology that can generate
electrical power ocean currents. It is a concept that has been
debated, researched and debated over several years. Unlike tidal
power stations that can only generate power for up to 10-hours per
day, installations like the proposed Bermuda project could
generate power throughout the day.
The installation at Bermuda may be the "proof of concept" and
the basis upon which larger and more powerful versions of this
technology may be developed. There are numerous other locations
around the world where prevailing ocean conditions would favour
larger installations that have higher generation capacity. While
the construction and installation cost of the technology may be
high, its operating cost over long-term is expected to be
comparable to that of shore-based hydroelectric installations.
Several favourable locations where undersea windmills may be
installed actually lie outside of heavily traveled commercial
shipping lanes. Some of the locations would include:
Strait of Florida:
The Gulf Stream flows from the Gulf of Mexico and a portion of
it flows into the 12-mile wide channel entrance to the channel
that lies between Key Largo and the southeast tip of Florida. This
channel gently converges over 15-miles to a width of 2-miles and
water depth is less than 150-ft. The current at this point in the
channel may be strong enough to enable undersea windmills to
generate an estimated 10-megawatts of electric power that may
mainly be used in the Florida Keys.
Bahamas:
A portion of the Gulf Stream flows from Florida Strait into the
Northwest Providence Channel of the Bahamas and through the
30-mile wide entrance to Little Bahama Bank that lies between
Grand Bahama and Great Abaco Islands. The Gulf Stream and
Equatorial Current merge in this region and flow into the Atlantic
through a 2-mile wide exit between Little Abaco and Great Abaco
Islands and also through an 8-mile wide exit that lies between
Little Abaco and Grand Bahama Islands. Undersea windmills capable
of generating over 100-megawatts of electric power may be
installed at these exists that are less than 150-ft in depth.
Trinidad and Tobago:
A portion of the South Equatorial Current diverges to the
northwest along the Brazilian coast toward the islands of Trinidad
and Tobago. These islands form an angle that captures a band of
ocean current that is 80-miles wide and within a distance of
20-miles, the band of current converges into the 20-mile wide
channel that lies between the 2-islands. This causes a strong
ocean current to flow through the channel where the water depth is
less than 150-ft near Trinidad and less than 600-ft near Tobago.
At the present time electricity on these islands is generated
using natural gas and diesel. In the long-term future, a "farm" of
large undersea windmills that could be installed in the channel
near Tobago and generate up to 1000-megawatts of power.
Indonesia:
As the Equatorial Counter Current moves eastward across the
Indian Ocean, the 45-degree angle of the Sumatra coastline will
deflect a wide band of ocean current toward the 45-mile wide
entrance to Sunda Strait that lies between Sumatra and Java. The
strait is 80-miles long and converges to a width of 10-miles near
its exist. The water depth rises from over 6000-ft in the Indian
Ocean (200-miles to the east) to under 150-ft at the narrowest
point in the strait. The converging strait would assure that a
fast current would flow through undersea windmills located at the
narrowest point. These units may need to be built to a restricted
height so as to allow ships with deep keels to pass overhead.
Alternatively, special shipping lanes may be implemented in Sunda
Strait so as allow the maximum height of windmills to operate
there.
Indonesia may have a potential of over 2000-megawatts of tidal
electric power, much of which could be sold to Singapore where
power stations consume expensive natural gas to produce power. A
portion of the Indonesian tidal power may be used to generate
hydrogen that would be sold to markets in Japan, China, Hong Kong
and possibly Singapore. If the Government of Indonesia is willing,
private investors could finance the installation of ocean power
conversion systems around Indonesia.
New Zealand:
There are two sites around New Zealand's South Island where
undersea windmills may be installed. The angle formed by South
Island and Stewart Island captures a 70-mile wide band of the West
Wind Drift Ocean Current and forces it to converge into the
20-mile wide Foveaux Strait. The water depth changes rapidly from
under 600-ft outside the strait to under 150-feet in the strait.
The combined convergence of width and depth causes a strong
current to flow in the strait where a "farm" of undersea windmills
may be installed and generate up to 1000-megawatts of power.
A portion of the West Wind Drift merges with the East
Australian Current and is deflected to flow in a northeasterly
direction along the 500-mile west coast of New Zealand's South
Island and into the 60-mile wide (north - south distance) entrance
to Cook Strait. Twice a day an eastward-moving band of tidal rise
from the Tasman Sea that is 450-miles wide would combine with this
ocean current. The converging angle made by New Zealand's two main
islands would funnel the tidal rise into the entrance of Cook
Strait that further converges to a width of 12-miles at its
narrowest point.
For power to be generated in Cook Strait, undersea windmills
may need to be installed between Cape Jackson and Kapiti Island
where the water depth is less than 600-feet. This channel may be
made narrower by building breakwaters and shallower by depositing
rocks and boulders on the channel floor. The reduced width and
depth of the flow of water would increase the speed of the current
that would flow through the artificially narrowed channel where up
to 2000-megawatts of electric power could be generated. A
designated shipping channel may have to be implemented in Cook
Strait at a future time if power from the ocean is to be generated
there. This power generation would be complimented by New
Zealand's high capacity for hydraulic energy storage.
Australia:
The West Wind Drift Ocean Current moves eastward along the
southern coast of Australia and into Bass Strait. The angle that
of southwest coast of the State of Victoria deflects a 165-mile
band of this ocean current into the 40-mile wide channel between
Cape Otway and King Island. The sea floor also rises over
120-miles from a depth of over 6000-ft outside the channel to
under 600-ft in the channel. This combined convergence of width
and height would assure that a strong tidal current would flow in
this channel where in the distant future, a "farm" of undersea
windmills may be installed between King Island and Cape Otway and
generate some 3,000-megawatts of power from the ocean current.
Other Sites:
There a numerous other suitable straits and channels around the
world where the combination of ocean currents, ocean tides,
changes in ocean depth and converging coastlines (wide entrance
and narrow exit) allow undersea windmills to be installed to
generate power. The list of such sites would include:
- Tsugaru-kaikyo channel between Hokkaido and Honshu in Japan;
- Muskeget Channel between Martha's Vinyard and Nantucket
Island, USA;
- The deeper channel in Strait of Dover (below depth of ships’
keels);
- The entrance to the Strait of Gibraltar (below depth of
ships' keels);
- Dardenelles, Turkey (below depth of ships' keels);
- Strait of Bab el Mandeb (below depth of ships’ keels);
- The channel between St Vincent Gulf and Encounter Bay,
Australia;
- The channel between Fraser Island and Eastern Australia;
- The channel between New Britain and Papua New Guinea
Technology:
Submersible windmills are being installed in rivers such as the
Hudson River near New York City. Bi-directional undersea windmills
are being tested for future use at ocean inlets where power would
be generated from the twice-daily change in ocean tides. As the
technology develops in the future, larger undersea windmills with
much greater generation capacity will appear. Power generation
from undersea windmills will be more consistent than power
generation from land-based windmills. The ocean tides and currents
are more reliable than prevailing winds and ocean water has
870-times the density of air. Undersea power generation technology
is likely to become more viable in the long-term future and may do
so in the absence of special tax breaks and subsidies from
governments. The pioneering installation in Bermuda may be the
forerunner of a technology that will serve the economic needs of
many nations in the long-term future.
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