APPENDIX 15
Memorandum submitted by Thropton Energy
Services
WATER CURRENT
TURBINES
A water current turbine converts the kinetic
energy in a flowing body of water. Unlike a conventional hydro
powered scheme, its installation requires no civil engineering
work apart from an anchor or mooring post. This flexibility makes
the turbine suitable for use in tidal streams and estuaries. The
turbine looks like an underwater windmill with a three bladed
rotor. The rotor is suspended from a floating pontoon, with the
transmission, generators, pumps etc. above the water. The two
designs of water current turbines developed by Thropton Energy
Services are the Garman Turbine and the Amazon Aquacharger which
meet the needs of different, specific markets.
Both turbines are decentralised power generators
applicable to areas without access to a large grid system. They
have been designed for manufacture and maintenance in regions
where they are likely to be used. As such, they are more likely
to be of interest to private users and development agencies working
internationally in the developing world. Detailed specifications
and applications are given in the attached documentation[4]
but the main advantages are:
— It uses renewable energy and needs
no fuel or oil,
— It is easy to operate and maintain,
— It has proved highly suitable for use in isolated
locations,
— It is non-polluting and almost silent when running,
— It needs no large scale civil engineering work,
— It can be moved should site conditions change,
— It is designed for local manufacture and maintenance,
— It can operate 24 hours per day without a full time
attendant.
The Garman Turbine was designed primarily as
a water-pumping machine for agricultural or community water supply
as this was viewed as the main need in its initial market, North
Africa. This turbine design has been adapted to generate electricity
and can also be used as a dual purpose machine, pumping water
or generating electricity as required by the user. Depending on
the resource available, it can produce up to 2kW output and is
a replacement for the three-inch diesel pump used in many agricultural
situations.
The Aquacharger is a battery-charging turbine
for domestic electrical supply or for use by village health centres,
schools or similar facilities. It is smaller than the Garman Turbine
and can produce up to 500W electrical power.
When manufactured in the region where they will
be used, the capital cost of the turbines is low compared to other
renewable energy systems. Its very low running cost means that
it becomes competitive with a diesel pump set after between one
and three years depending on local price of fuel and materials.
The extent of the resource available worldwide has yet to be established
but surveys completed in target countries have shown that the
resource and the need are sufficient to sustain local manufacturing
bases (see attached paper "Water Current Turbines for Pumping
and Electricity Generation" by PG Garman & B A Sexon).[5]
At present the Garman turbine is being manufactured
and used on a small scale in the Sudan. The Aquacharger is manufactured
by Marlec Engineering of Corby, under licence. It is undergoing
field trials in South America where it has been enthusiastically
received by the initial users.
The main obstacle to the widespread use of this
technology is the high initial cost of establishing the infrastructure
required to support its installation and maintenance. The majority
of renewable energy systems are site specific and thus accurate
site surveying is essential to ensure appropriate system design.
Although running costs are low, the capital cost of a renewable
energy system is higher than an equivalent diesel generator. To
compensate for the initial high cost, long service life and high
reliability are a requirement and so a very high standard of installation
with meticulous attention to detail is essential. When something
does go wrong there must be back-up readily available in the form
of qualified technicians and spare parts. The hardest task in
the dissemination of any renewable energy system is to put in
place the infrastructure required for surveying, installation
and maintenance without adding unacceptable amounts to the unit
cost.
The provision of these services for such small
and of necessity low cost systems is not an attractive commercial
proposition for the large companies in capital cities which are
capable of manufacturing complete sets (including generators).
Thus, if a significant fraction of any renewable energy resource
is to be exploited, investment in training of local technicians
will be required (eg the staff of small engineering firms, that
are already providing services). It is at this point that assistance
from external government and international agencies can play an
important role.
After completing the design to production standard,
Thropton Energy Services was able to establish local manufacture
in Sudan because we were in a position to incorporate the turbine
into existing systems within that country. Financial assistance
from the Sudan government and the German Development Service made
it possible to provide equipment and additional training to qualified
technicians already working for a local farming organisation.
With the support of Thropton Energy Services standard procedures
were set up that enabled the technicians to survey potential sites,
install and maintain turbines. The turbines are manufactured in
an industrial unit attached to an engineering college in the region.
This industrial unit had been set up in the 1980s as part of an
unrelated British government funded project at the engineering
college. Without the direct and incidental support of the above
agencies it is unlikely that the manufacturing base for the turbine
would have been established or sustained at any level.
In conclusion, for this type of technology to
be widely adopted, financial support is needed to assist projects
beyond the demonstration phase. It is in the area of dissemination
of an existing technology that aid from government and other agencies
can be of real benefit to small development companies.
9 February 2001
4 Not printed. Back
5
Not printed. Back
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