Collision risks between marine mammals and tidal energy devices are poorly understood and this perceived risk of collision remains a major issue for the in-stream tidal energy industry, regulators, and stakeholders. Without additional information on the level of risk there is a potential constraint on the scale of future tidal energy development. This paper presents the development of a new modelling approach to understand the risk posed by a novel tidal technology. Minesto has developed a tidal power plant named Deep Green. This technology comprises a kite/wing and a tether running to a single anchor point. The device leverages the tidal current to lift the hydrodynamic wing; the power plant essentially flies in the water column in a ‘figure of 8’ shaped pattern. Collision probabilities (CP) varied depending on the anchor point of the device, the current speed (tidal state) and swimming behaviour of animals. Overall CP estimates varied , with between 0.78 - 2.69% of animals that passed through the water column were predicted to collide with the device. Simulations where animals were actively swimming with the current had lower CP than when passively drifting with the current. Differences in CP were observed between anchor positions (surface: 1.1 - 1.5%; seabed 0.8 - 0.9%) for active animals. Animals were predicted to be more likely to collide with the tether than the kite (61 - 80% tether; 20 - 39% kite). It is difficult to directly compare with other tidal projects due to different methods and data used to estimate collision risk across projects. However, on average, the risk predicted here is lower than estimates for the same species at other sites for different devices. We will also present next steps for such assessments, including enhanced collision/strike risk models (incorporating animal movement), data gaps in model parameterization (and consequent risk levels), near-field monitoring tools presently being used to address these limitations and population-level modelling.
Advancing a Key Consenting Risk for Tidal Energy: The Risk of Marine Mammal Collision for In-Stream Tidal Energy Devices
Title: Advancing a Key Consenting Risk for Tidal Energy: The Risk of Marine Mammal Collision for In-Stream Tidal Energy Devices
April 28, 2015
Conference Name: 3rd Marine Energy Technology Symposium (METS)
Conference Location: Washington DC, USA
Notice: This material may be protected by Copyright Law.
Booth, C.; Sparling, C.; Wood, J.; Tollitt, D.; Scott-Heyward, L.; Rexstad, E.; Hultgren, Y.; Johnsson, M.; Knutzen, E. (2015). Advancing a Key Consenting Risk for Tidal Energy: The Risk of Marine Mammal Collision for In-Stream Tidal Energy Devices. Paper Presented at the 3rd Marine Energy Technology Symposium (METS), Washington DC, USA.