Assessing Underwater Noise Impact of Offshore Renewables

The project scope will also involve Kongsberg Maritime determining the acoustic impact associated with installing and operating the Oyster device when it is subsequently operating in a high energy wave environment. This phase will take place off the north-west coast of the Isle of Lewis.

The Oyster device has been developed by Aquamarine Power to capture wave energy from near-shore sites and convert it into clean sustainable electricity.

The next-generation Oyster 800 wave energy device was recently installed at the EMEC site in Orkney, where the installation noise was captured by Kongsberg Maritime as part of the project scope, and there are plans to install two further Oyster devices at the same site in 2012 and 2013. Each device will have a generating capacity of 800kW.

Having completed the first phase of the project at Billia Croo, Kongsberg Maritime will shortly embark on measuring the underwater noise once the Oyster device is operating. These activities undertaken by Kongsberg Maritime will allow the environmental impact of the wave energy device outside the EMEC site to be assessed in context.

As part of the project, Kongsberg Maritime used its autonomous underwater noise recording system known as RUNES to conduct baseline noise measurement at the Isle of Lewis site. The RUNES system, simple in its deployment method, is placed on the seabed over an extended period of time while recording baseline noise prior to any construction or installation work being carried out.

Using the RUNES system removed the need for surface support vessels and personnel during the main operation, helping to reduce costs and increase operational efficiency. The absence of trailing hydrophones and vessel noise also meant that the data collected at the Isle of Lewis site was of significantly higher quality, allowing for clearer interpretation and analysis.

The data collected during the baseline noise studies, combined with the underwater noise data gathered at the Billia Croo site, will contribute to an assessment of the potential effects of underwater noise on marine mammals, fish and diving birds at the site once the Oyster device is installed and operational.