Low Density Tidal Energy Arrays Minimize Impact

by Cassandra Burgess

The configuration of a tidal energy array partially determines the level of environmental impact. In determining the optimal configuration for a particular area, it is important to consider not only power output, but also environmental impacts. Fallon, et al. discuss the impacts of a tidal energy array located in Ireland in their 2014 paper. They use a two dimensional model and average speeds over the depth of the channel. This simplifies the modeling process, but it also overestimates some of the impacts. They then analyze grid spacing for turbines, with turbines spaced 0.5, 2, and 5 times their diameters apart. The model indicated that the 5 diameter spacing had the least environmental impact. It decreased velocities by 19.9% less than the 0.5 diameter spacing outside the grid, and increased flood velocities by 27.3% less. The 5 diameter spacing also changed the tidal range of heights by only 1% while the 0.5 diameter changed them by 6.4%. Because the 5 diameter spacing has significantly less impact on the hydrodynamic environment around the turbines, the authors conclude that it is desirable to use low density arrays when possible. Continue reading