This report was prepared to the OES IA under ANNEX II: Guidelines for Development and Testing of Ocean
Energy Systems Task 1.2 Generic and site related tidal data
INTRODUCTION
In 2001 the International Energy Agency (IEA) established an Implementing Agreement on Ocean Energy Systems (IEA-OES) as a means to foster international collaboration on research and development, technology demonstration and information exchange related to ocean energy systems. Within this framework, an international working group, known as Annex II, was formed to develop recommended practices for laboratory testing and evaluation of ocean energy systems and, in this way, to improve the comparability of experimental results from different sources. Activities included collecting and analysing information on testing facilities and testing procedures, developing guidelines for presenting technical data, and developing guidelines for the assessment of system performance. In 2006 the mandate of Annex II was extended to consider the performance of prototype ocean energy systems operating in the marine environment and to develop and provide the necessary basis in order to present the performance of different systems in a comparable format.
This report has been prepared as a voluntary contribution to the IEA-OES Annex II project. It hopes to assemble and present useful guidance concerning methods to describe and assess the energy resource associated with tidal currents. The information can be used to help assess the scale of the energy resource at a site and the nature of its temporal fluctuations. Moreover, a simple method is described to estimate the scale and temporal fluctuations of the power that would be produced if an energy converter were to be installed at the site. This type of information is a necessary basis for informed decisions concerning resource assessment, regulation, site selection and the forecasting of energy production.
The report includes a brief general discussion of the origin and nature of tides and tidal currents. The equations that can be used to calculate the kinetic energy associated with a tidal stream, and the power that could be generated at a site, are presented. Some of the more important sources of uncertainty are also identified and discussed. Finally, kinetic energy resource assessments for two sites in Canada are presented to demonstrate the methods that are described. The first case study considers a site in the upper Bay of Fundy, while the second examines a site in St. Lawrence River estuary near Quebec City.
