Collision risk modelling for tidal energy devices: A flexible simulation-based approach

Abstract

The marine renewable energy industry is expanding as countries strive to reach climate targets as set out in the Paris Agreement. For tidal energy devices, the potential risk for animals to collide with a device, particularly its moving parts such as rotor blades, is often a major barrier in the consenting process. Theoretical work surrounding collision risk has commonly made use of a formulaic modelling approach. However, whilst providing a platform to assess conventional horizontal axis tidal turbines, the frameworks applied lack the flexibility to incorporate novel device designs or more complex animal movement parameters (e.g. dive trajectories). To demonstrate the novel simulation-based approach to estimating collision probabilities a hypothetical case study was used to demonstrated how the approach can assess the influence that variations in ecological and behavioural data had on collision probabilities. To do this, a tidal kite moving in a 3D figure-of-eight trajectory and a seal-shaped object were modelled and variations to angle of approach, speed and size of the animal were made. To further improve the collision risk estimates, results of the simulations were post-processed by integrating a hypothetical dive profile. The simulations showed how variation in the input parameters and additional post-processing influence collision probabilities. Our results demonstrate the potential for using this simulation-based approach for assessing collision risk, highlighting the flexibility it offers by way of incorporating empirical data or expert elicitation to better inform the modelling process. This framework, where device type, configuration and animal-related parameters can be varied with relative simplicity, on a case-by-case basis, provides a more tailored tool for assessing a diverse range of interactions between marine renewable energy developments and receptors. In providing a robust and transparent quantitative approach to addressing collision risk this flexible approach can better inform the decision-making process and aid progress with respect to developing a renewable energy industry in a sustainable manner. Therefore, the approach outlined has clear applications that are relevant to many stakeholders and can contribute to our ability to ensure we achieve sustainable growth in the marine renewable energy industry as part of a global strategy to combat climate change.

The Use of Animal-Borne Biologging and Telemetry Data to Quantify Spatial Overlap of Wildlife with Marine Renewables

“…The representativeness of the polygons could also help to determine the need for additional data to increase sample size and/or temporal coverage (e.g., seasons, years). Should the polygons be deemed sufficiently robust, relevant complementary data from devices (e.g., depth) could be used to populate collision risk models to estimate collision mortality [106][107][108][109][110].…”

A Review of Modeling Approaches for Understanding and Monitoring the Environmental Effects of Marine Renewable Energy

“…Two related analytical approaches to estimating the interactions between animals and tidal turbines based on wind turbine collision modeling are the encounter rate model (ERM) and the collision risk model (CRM). A spatial simulation approach can also estimate the probability of contact [170]. At the population level, the exposure time population model (ETPM) estimates the fatal collision rate that leads to a specified negative effect on the population.…”

“…A four-dimensional simulation model (3D representation of a device and animal over time) was used to estimate the risk of a tidal kite colliding with seals [180], accounting for the path of the tidal kite's movement. Horne et al [170] extended this model to include more detail about the seals and their dive profile. Rossington and Benson [181] developed an agent-based simulation of fish passing by a tidal turbine as part of a biophysical model that included typical fish behavior in a flow and estimated collision risks.…”

Ecologically-sustainable futures for large-scale renewables and how to get there

“…It is quite clear and can be easily modelled to show that increased mortality can have significant effects on populations as the death of adults, especially for long-lived animals, will very rapidly lead to population declines. However, only recently have collision models stepped up to state-of-theart simulation models [22]. Recently, there has also been the initiation of a modelling framework being developed to finally bring together all the direct effects of collision, displacement and disturbance [23].…”