The Marine Renewable Energy Strategic Framework project has investigated the potential marine renewable energy resource of Welsh Territorial Waters (TWs) and considered potential scenarios for the sustainable development of that resource primarily as an aid to policy development and also an indicator of resource for potential developers. This report is Phase 1 of the Assessment of Risk to Diving Birds from Underwater Marine Renewable Devices in Welsh Waters and reviews potential risk to diving birds from marine underwater renewable energy devices (MUREDs). The review is based on the results of desktop research into device type and diving bird ecology, and also includes examination of existing Environmental Impact Assessments (EIAs) of MUREDs, together with research from the European Marine Energy Centre (EMEC). MUREDs considered in this report fall into two broad designs: tidal stream and wave power. Tidal stream devices are similar to submerged wind turbines and harness the energy of fast ocean currents around headlands, inlets and channels. The four categories of tidal stream device are: horizontal axis turbine, vertical axis turbine, oscillating hydrofoil and turbines which exploit the Venturi effect. Wave power devices are positioned on or near the sea surface and are driven by wave motion. The six categories of wave power device are: attenuators, point absorbers, oscillating wave surge converters, oscillating water columns (OWCs), overtopping devices and submerged pressure differentials.
A literature review presents the underwater ecology of 35 diving bird species occurring in Welsh waters. Species population and distribution are discussed, along with foraging range, foraging depth, dive profile, underwater vision and prey preferences. Species discussed are of conservation importance at an international or national scale due to their relative abundance in Welsh waters, their citation in internationally or nationally designated sites, or their legal protection status. Potential risks to diving birds posed by these MUREDs are: direct habitat loss; displacement; risk of collision; risk of entrapment; and impacts arising from disturbance or displacement of prey. Risk also increases with the size of device array – the greater the rotor-swept volume of water, the greater the risk. Risk also varies with exposure of the devices’ moving parts: where moving parts are fully exposed risk will be higher than where they are partially enclosed.
This report therefore presents an extensive literature review of the underwater behaviour of diving birds. The aim is to inform assessment of the suite of species that are most at risk from the potential impacts of a specific wave or tidal development in Welsh offshore waters. Once identified, this suite of species would form the list of target bird species for baseline surveys during the EIA process. The trialling of survey methodologies appropriate for the collection of baseline EIA ornithology data is being undertaken as part of the second phase of this project.
The Approach to Sustainable Development Report presents the final outputs of the Marine Renewable Energy Strategic Framework (MRESF). The MRESF will be an essential management tool for the sustainable development of wave and tidal energy in Wales.