Offshore Wind Farms
Offshore wind projects are expected to increase significantly in number and magnitude, amplifying their potential impact on the marine environment. Offshore wind projects have the potential to introduce noise to the marine environment via the construction process, turbine operation, and increased vessel traffic due to construction and maintenance, but pile driving associated with the construction process generally introduces the highest noise levels. Passive acoustic monitoring provides a unique opportunity to track noise levels, biological activities, and to characterize the local marine soundscape before, during and after wind farm development. The loud impulses produced during pile driving are believed to be sufficiently powerful to affect the hearing of marine mammals. For this reason, hydrophones are often used to monitor for animals before pile driving starts and during piling operations. Ocean Sonics can manufacture a reduced sensitivity hydrophone specifically for pile driving operations.
The world’s tides, ocean waves and river currents all contain kinetic and potential energy that can be used to drive turbines and produce electricity—reducing our dependence on fossil fuels. The energy in waves comes from the movement of the ocean and the changing heights and speed of the swells. Waves get their energy from the wind. The wind comes from solar energy. Waves gather, store, and transmit this energy thousands of miles with little loss. As long as the sun shines, wave energy will never be depleted. Wave power is renewable, green, pollution-free, and environmentally invisible, if not beneficial, particularly offshore.
Tidal energy is a renewable source of electricity which does not result in the emission of gases responsible for global warming or acid rain associated with fossil fuel generated electricity. Unlike wind and waves, tidal currents are far more predictable and reliable. We can predict the movement of the tides today, tomorrow, and in 300 years from now. Tidal barrages are undersea tidal turbines, like wind turbines but driven by the sea, harnessing undersea currents. Tidal turbines do not have to spin as fast as windmills to generate power, because water is roughly 800 times denser than air. Energy can be harnessed from the tides in two ways: using the change in height of the tides, and using the flow of the water.
The Ocean Observatories Initiative (OOI) Regional Scaled Nodes (RSN) had requirements for very broadband hydrophones with good noise floor characteristics and a wide dynamic range. The icListen HF hydrophones satisfied these requirements at a reasonable cost. The hydrophones were quite easy to use out of the box, and easily passed our intensive First Article tests centered on assuring any instrument will not interfere with or corrode any other instrument. Customer support has been quite good, with very detailed questions answered quickly and accurately.
Skip Denny Principal Ocean Engineer, RSN Applied Physics Lab, University of Washington.