Abstract
The reality of climate change has led to an increased desire for renewable energy technologies. Recently, ocean energy has received increasing attention from the scientific community. Tidal energy specifically has immense potential, and as it is incredibly predictable there is the possibility of continuous energy generation from the ocean with the combined use of energy storage systems and tidal energy converters. However, before a mass implementation of tidal energy devices, their environmental impacts need to be better understood, and, in a warming climate it is critical to understand how the changing climate will influence these impacts. In this thesis, global climate models were combined with an Underwater Acoustic Simulator (UAS) to quantify the sound propagation from tidal turbines. This model was applied to 9 sample locations within Europe’s marginal seas simulating sound propagation in modern day climatic conditions (seawater temperature and salinity) and in projected 2050 conditions. The turbine modelled was a 6-m OpenHydro open centre turbine due to its already environmentally conscious design. The locations were in the Baltic Sea, North Sea, and English Channel due to the propensity for tidal and wave energy in this region. The resulting sound propagation from the two simulations were subtracted from each other to calculate the change in Sound Exposure Level (SEL) at each location. The simulated changes at each location were averaged and fitted to a normally distributed probability density function (PDF) to predict how underwater sound propagation changes with the climate. In regards to spatial differences the results suggest minimal impacts from temperature and salinity differences between locations on underwater sound attenuation, but relatively large impacts from differences in bathymetry and topography. In regards to changes over time the results showed that SEL tends to decrease with climate change, centering at around a -0.5 dB change. This is a very small change in comparison to the 185 dB of noise created by a tidal turbine. More to the point, six of the nine locations predicted an insignificant average absolute change (less than ± 0.3 dB). These results are helpful in understanding one of the many impacts of climate change on the planet’s key environments, and expanding on how tidal turbines affect the ecosystem in which they are placed.