IMPACT OF TIDAL STREAM ENERGY EXPLOITATION ON ESTUARINE HYDRODYNAMICS

Proceedings of the International Conference on Coastal Engineering

Victor Ramos¹  Angela Vazquez²  Rodrigo Carballo¹  Marcos Sanchez¹  Miguel Álvarez²  Gregorio Iglesias² 

[1] University of Santiago de Compostela

关键词: Tidal stream energy impact;    3D numerical modelling;    transient circulation;    residual circulation;   

DOI  :  10.9753/icce.v34.management.22

学科分类：建筑学

来源: Coastal Engineering Research Council

【 摘 要 】

During the last years there has been an increasing interest towards the exploitation of marine energies and, in particular, of tidal stream energy. Although the impact of tidal stream farms is expected to be much lesser than that the conventional barrages, there are numerous environmental variables likely to be altered. This is of particular interest in the case of the Galician Rias that present complex 3D flow patterns, which is one of the main causes of their large oceanic productivity. Therefore, its modification as a result of tidal energy exploitation should be analysed by means of 3D modelling. The present study investigates the environmental impacts of tidal energy extraction in the Ria de Ortigueira located in the NW of Spain. For this purpose, a numerical model was implemented in Ria de Ortigueira (NW Spain), a promising region for tidal stream energy exploitation. First, the model was successfully validated on the basis of field measurements of water levels and magnitude and direction of the tidal currents, then, it was used to describe the potential effects resulting from the operation of a previously proposed tidal stream farm during typical winter and summer conditions. For this purpose, the momentum sink approach was used. Overall, it was found that the resulting transient flow modifications were concentrated in the vicinity of the farm, with nearly negligible effects outside the inner ria. Furthermore, important asymmetry effects were also observed; although the inner part of the estuary is flood dominated, the complex geometry of this area causes that the most important effects occur during the ebb with modifications of up to 15 % of the unaltered flow, which represent an impact almost twice as strong as that during the flood. Finally, the effects on the residual flow are of the same order, in terms of percentage of velocity variation, as in the case of the transient flow; however, they extend over a wider region, affecting the middle ria, where a complex 3D circulation pattern (a positive estuarine circulation) develops.

【 授权许可】

Unknown