Methodology for a Decision Support Tool for a Tidal Stream Device

Introduction

Overall diagram of the project

In contrast to renewable energy technologies such as wind, wave, and solar energy, tidal stream energy is a predictable resource. Additionally, the equipment has minimal visual and environmental impacts, as well as low operating costs. All of these advantages make it a key strategic component of the future energy mix of the United Kingdom.

However, the technology is not as advanced as other renewable energy devices and work remains in terms of developing the technology to a commercial scale. The remote location of the most energetic sites in the UK can lead to high installation costs and the need for expensive reinforcements to the local electricity grid. Additionally, with only a few horizontal axis turbines being tested at present there is little publicly available feedback data to base designs on, especially at the scoping stage of a project.

In this scenario a reliable methodology for developing a complete tidal stream turbine project, including consistent tools to complete different aspects of the design of a tidal turbine and the expected economic performance, becomes essential.

Aims

To develop a methodology that supports the decision making process in the design of cost-efficient Tidal Stream devices, creating compact, reliable and efficient engineering tools that provide a techno-economic assessment of a tidal energy project.

Objectives

With this aim in mind and covering all the issues – from the site selection and the analysis of its available resource, to the final energy production and project’s profitability – the following objectives were defined:

         •   To identify the physical constraints due to the Wave and Tidal Interaction.
         •   To analyse the tidal resource of the site by calculating Tidal Exceedance Curves.
         •   To generate the optimum blade that maximizes the energy production using Blade
              Element Momentum Theory.
         •   To quantify the effect of the calculated loading profile on the design life of the rotor.
         •   To evaluate the Techno-Economical Analysis of a Tidal Stream Energy project.

Deliverables

The five objectives of the overall project shaped the five deliverables defined below. These, as well as the corresponding documentation, are available throughout the website for use and further modification.

         •   A Wave/Tidal Interaction Tool for analysing the selected site.
         •   A Tidal Exceedance Curve Calculator for assessing the available resource.
         •   A guide for the correct use of the Blade Element Momentum software HARP_Opt for
              Tidal Stream devices.
         •   A Material Analysis Tool for evaluating blades of different materials.
         •   A Techno-Economic Analysis tool for Tidal Stream projects.

Deliverables diagram