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Compact tidal generator could reduce the cost of producing electricity from
flowing water
The University of Southampton's minimalist design significantly reduces
the number of moving parts, and is fully assembled prior to installation.
Estimates five years to commercialization.
HIGHFIELD, SOUTHAMPTON, UK -- What happens if you run an electric motor
backwards? That is exactly what researchers Dr. Steve Turnock and Dr. Suleiman
Abu-Sharkh from the University of Southampton asked themselves after they had
successfully built an electric motor for tethered underwater vehicles.
The well-known answer to this question is that it stops being a motor and
becomes a generator. Instead of using electricity to turn a propeller and drive
the vehicle along, the flow of water turns the propeller, generating
electricity.
What's new about the Southampton design is its simplicity. "This is a
compact design that does away with many of the moving parts found in current
marine turbines. It's a new take on tidal energy generation," says Turnock.
Most current tidal-stream generators are essentially wind turbines turned upside
down and made to work underwater. They often include complex gearboxes and move
the entire assembly to face the flow of the water. For example, they turn a
half-circle as the tidal current reverses direction. Gears and moving parts
require expensive maintenance. When they are used in seawater, protection from
rust and corrosion can involve sealed housings for joints and other added
components. This pushes up the cost of running the turbines, a cost that is
passed on to the consumers of the generated electricity.
The Southampton design does not need to turn around because the design of its
turbine blades means that they turn equally well, regardless of which way the
water flows past them. The blades are also placed in a specially shaped housing
that helps channel the water smoothly through the turbine.
Another beauty of the Southampton design is that everything is wrapped in a
single package that can be prefabricated so there will be few on-site
construction costs. "Just drop it into flowing water and it will start
generating electricity. It will work best in fast-flowing, shallow water,"
says Turnock, who foresees rows of these devices secured to sea floors and
riverbeds.
The present prototype is just twenty-five centimetres across. The research
team now plans to design a larger model with improved propeller blades that will
further increase the efficiency of generating electricity. All being well, the
team envisages the generator becoming commercially available within five years.
Previous Work
In the early 2000s, Abu-Sharkh, Turnock and their team used funding from the
Engineering and Physical Sciences Research Council (EPSRC),
and from industry, to create a novel tethered underwater vehicle thruster. Their
design used electricity to turn a ducted propeller, providing thrust to control
the vehicle's position and speed. Tethered underwater vehicles are extensively
used in the offshore industry for conducting underwater inspections and for
robotic manipulation.
An overall propulsion system based on electrical thrusters is much smaller and
lighter than the hydraulic thrusters that have been traditional in tethered
underwater vehicles. Reducing the weight of the vehicles makes them cheaper to
operate, as it takes less energy to move them.
Manufactured under license by the local Hampshire company TSL, these thrusters
are already in use around the world for a variety of underwater vehicle
applications. It was out of the fundamental research involved in the
hydrodynamic and electrical design of the integrated electric thruster that the
concept of this new electricity generator sprang.
About The Engineering and Physical Sciences Research Council
The EPSRC, which is funding this present tidal project as well, is the UK's main
agency for funding research in engineering and the physical sciences. To help
the nation handle the next generation of technological change, this agency
invests more than £500 million a year in postgraduate training and in research.
The areas covered range from information technology to structural engineering,
and mathematics to materials science.
This research forms the basis for future economic development in the UK, and
hope for improvements for everyone's health, lifestyle and culture. EPSRC also
actively promotes public awareness of science and engineering.
# # #
SOURCE
ACKNOWLEDGEMENT:
CONTACT:
Dr Stephen Turnock
University of Southampton
tel: +44 (0)2380 592488
e-mail: <steve {at} ship.soton.ac.uk >
See also
Page posted by Sterling
D. Allan June 13, 2006
Last updated June 16, 2006
visits since June 16, 2006
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