AEA Technology Reviews Tidal Electric's Technology

AEA Technology, PLC, is the U.K. government’s technical consultant on a broad range of scientific and technical issues. AEA reviewed Tidal Electric’s technology, and several excerpts follow:

Excerpts from AEA Technology plc Report (# ED03922/R1)
Author: T W Thorpe
Reviewed & Approved by H Parkinson
Title: Swansea Bay Tidal Scheme (April, 2002)

Editor’s 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.