Swedish company CorPower Ocean is collaborating with Portugal-based WavEC Offshore Renewables to deliver an environmental monitoring program with the goal of verifying the environmental impact of its wave energy technology.
Phase one which included underwater noise baseline campaigns has been concluded at the HiWave-5 Wave Energy Park off the coast of Aguçadoura, in northern Portugal, and involved analysis of ambient noise in the project area prior to installation.
Furthermore, two campaigns, carried out during January and May last year, recorded noise during two different seasons of the year.
WavEC Marine Environmental Researcher and Project Manager Inês Machado noted that the initial campaign had seen the recording of natural sources of noise including the action of wind on the surface, breaking waves, water flow, rain, sediment movement and the presence of marine fauna.
In addition, the parties recorded anthropogenic noise sources such as maritime traffic, largely related to fishing activity, said to be the biggest contributor to noise in the area.
“The results reveal that the SPL (Sound Pressure Level) was similar between the January and May campaigns. However, it was possible to conclude that the predominant sources contributing to ambient noise levels at lower frequencies up to 1kHz was maritime traffic at distance. On the other hand, the contribution of marine traffic to ambient noise levels was lower in January, where cetacean vocalizations were more predominant sources of ambient noise,” Machado said.
The HiWave-5 Project will consist of four wave energy converters with a combined 1.2 MW power rating, fixed to the seabed through a system of perforating anchors.
Project installation is divided into two stages, beginning with the demonstration and certification of a full-scale 300 kW C4 prototype later this year, and a second phase that will involve the demonstration and certification of a set of three C5 devices.
According to CorPower, acoustic data was collected using three autonomous hydrophones installed 20 meters from the seabed. Results will be used as a benchmark against underwater noise levels during the C4 operation.
“We now have solid data regarding current noise levels at the Aguçadoura test site. Using these benchmarks, we will be able to conduct a thorough assessment of the project’s contribution to ambient noise during different operating states and seasons,” said Enric Villarin , Project Manager at CorPower Ocean.
“We look forward to the next stage of the underwater noise monitoring campaign during the operational phase of the HiWave-5 Project, helping prove the low environmental impact of wave energy technology.”