Abstract
When we hear about offshore energy in the news media and other popular information sources, images of oil platforms and, more recently, wind farms flash across our screens. However, there is a new, rarely known sector of offshore energy under development that is focused on harnessing the renewable power contained in ocean waves and currents and converting it to electricity. These new technologies termed marine energy converters (MECs) are the topic of this article. They not only have the potential to make a significant contribution to our energy needs but may also generate new sources of anthropogenic sounds in the oceans that require measurement and characterization to ensure that there are no harmful effects to marine life.
Although many of these new technologies produce sound during their operations, making actual acoustic measurements of these devices in the high-energy ocean waves and tidal currents necessary for generating meaningful amounts of electrical power is anything but trivial. This type of energy conversion, known as marine energy, is an emerging renewable resource that is now in its testing and development phase. Because MECs contain multiple moving parts as well as electrical generation equipment, they can produce underwater noise audible to marine life, such as the whales, fishes, and sea turtles commonly observed around marine energy sites. Therefore, the sounds generated by these new technologies are of high interest to researchers, regulators, and industry developers. Whenever a new MEC is installed for testing, researchers deploy hydrophones to understand the characteristics of the sounds it generates. In turn, they inform regulators about what to expect from these new technologies while helping the technology developers understand what they might do to make them quieter during their next round of testing. However, placing a hydrophone in a tidal stream or near a surf zone is not only logistically challenging for the safe deployment, recovery, and survivability of the sensors but is often equally as tough for the scientists and engineers making those measurements in the pitching and rolling waves and strong currents.