The EBAO project was developed to establish robust modelling methodologies that could be embedded into the marine energy project design cycle in order to protect, and even enhance, the natural environment while enabling array designs to maximise energy production. To achieve this, a unique consortium was assembled comprising marine environmental modellers with expertise covering the physical environment, marine ecosystems, acoustic propagation and marine mammal behaviour. The remit of the project included wave and tidal energy and, unusually for a project of this nature, offshore wind. Wind was included to enable contrasts between levels of industry maturity and scales of deployment, thus providing a wide range of potential case studies and illustrating future challenges that may be faced by the wave and tidal industry.
The aim of the project was to identify issues of environmental concern and uncertainty, develop new modelling approaches to address these issues, and demonstrate how the developed methodologies could be included in an integrated design process. Although there are variations from site to site, the usual approach to marine energy array design follows an iterative cycle similar to that shown in Figure 1. The process is based primarily on the physical site characteristics and available resource, and accounts for physical and environmental constraints in informing the design of devices, moorings and array layout for maximum financial return. Once the design process is complete, an environmental impact assessment is performed to ensure all potential impacts fall within acceptable levels, with mitigation measures established where necessary.
However, the EBAO team envisaged a process that integrates ecological acceptability throughout the design cycle (Figure 2). The local ecology would be included with the physical environment when characterising the site and a parallel environmental assessment cycle would sit within the standard design process. Information would be passed between the design and environmental assessment cycles as part of a two-way process, enabling the ongoing design process to inform environmental modelling studies, and results from the environmental work to feed back into the design cycle. An example of how this approach might work in reality is the design of channels for vessel access and maintenance within an offshore wind array. Such channels may also be highly beneficial to marine mammals attempting to swim through the site because there will be lower noise levels than in the main array. If initial plans for the channel dimensions are passed to the acoustic and mammal behaviour modellers, the likelihood of animals using the proposed channels can be assessed and any necessary changes to benefit animal movement proposed. A solution that meets the needs of both the engineering design and the local marine species can therefore be found at an early stage in the process.