Assessing Tidal Current Power Resources

Tidal current energy is looked upon worldwide as a largely untapped, potentially significant and reliable source of energy. Countries, such as the United Kingdom and Canada, are working towards the implantation of tidal turbine farms in order to exploit this promising form of renewable energy. One of the barriers to further developing tidal energy extraction is the difficulty of accurately assessing the extractable energy or realisable tidal current output of a given site. Various numerical models for site assessments currently exist. Three of them, the Kinetic Energy Flux and two models, named GC05 and V10, which take into account the effect on the flow of the introduction of turbines are described, discussed and used throughout this work. Data regarding 239 channels worldwide have been collected. These data are used to investigate the possible existence of patterns between channel characteristics or parameters and channel potential estimates. New upper limits for the tidal current potentials of the UK and Ireland are calculated using the collected data and the most advanced model - V10, and compared to previous values. Finally, resource assessments, based on realisable power, are produced using the V10 model and the Seagen turbine characteristics. For these resource assessments, limits of up to 20% with regards to the blockage ratio and the reduction in flow speed for a given channel are put in place. These results show that a substantial fraction of the upper tidal current potential limit can be realised with only a 20% blockage ratio and a 20% reduction in flow speed for most channels