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AEA Technology Report
AEA
Technology plc is the UK governments technical consultant on a broad
range of scientific and technical issues. AEA reviewed Tidal Electrics
technology and following are several excerpts:
Excerpts from AEA Technology
plc Report (# ED03922/R1)
Author: T W Thorpe
Reviewed & Approved
by H Parkinson
Title: Swansea Bay Tidal
Scheme (April, 2002)
Editors Note: Descriptive
headlines for each excerpt are in bold and are not included in the AEA
Technology report. All other words are direct quotes from the report.
Innovativeness
of Design
Tidal Electric Swansea Bay Limited (Tidal Electric) has developed a new
approach to tidal power generation, which offers the potential for considerable
improvement over the earlier barrage schemes.
Environmental
Issues
Providing it can be demonstrated that no interference will occur to the
Crymlyn Burrows and that sufficient consultation takes place with interested
parties, the environmental impacts of the proposed scheme are likely to
be acceptable. Indeed, it is possible that the scheme could have significant
environmental benefits, such as protecting the Crymlyn Burrows or becoming
a wildlife habitat. However, the environmental pros and cons can be confirmed
only after the full Environmental Impact Assessment to be conducted in
the manner outlined above.
Two-directional Generation
The Tidal Electric scheme is designed
to produce power on both the ebb and the flood tides, thereby increasing
the power output by roughly a factor of double.
Reliability
of Turbine/Generators
The relatively low head of the scheme (<15 m) and variation in head
(due to gradual depletion of the reservoir during electricity generation)
indicate the use of Kaplan turbines. This is a mature technology, albeit
primarily in fresh water. Its implementation in seawater would require
the judicious selection of materials but should not prove a problem. The
rest of the mechanical and electrical plant should comprise conventional
technology, similar to a hydroelectric scheme.
Load
Factor
The flow characteristics and output have been modelled by Montgomery,
Watson and Harza for schemes in other locations but not yet for Swansea
Bay. These models show a consistent increase in load factor from 48% to
60% on going from the single to triple pool scheme
..the higher load
factor of the multi-pool scheme will increase the flexibility and dispatchability
of the output. This, in turn, will allow the electricity to be sold at
times of higher demand and higher prices, thereby increasing the revenue
from the output and resulting in improvements in the effective economics
of the scheme.
Profitability
the scheme is predicted to be capable of producing positive rates
of return at typical prices paid for electricity and high rates of return
at the enhanced prices paid for generation by new renewables.
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