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Could the proposed Humboldt offshore wind farm impact ocean upwelling?

Our coastal marine ecosystems are dependent upon a phenomenon known as coastal upwelling (1), which occurs when strong, consistent northwesterly winds constantly push surface level coastal water offshore that is then replaced by much cooler and more nutrient-dense deep water. By bringing these nutrient-dense waters upwards, coastal upwelling makes our vibrant coastal marine ecosystems possible. These complex ocean-atmospheric dynamics also generate the coastal fog that nourishes our coastal forests and rivers.

A diagram of upwelling, in which "surface winds push surface water away from an area," "warmer surface water moves offshore," and "deeper, colder, nutrient rich water rises up from beneath the surface to replace the water that was pushed away," to where phytoplankton and zooplankton live.

Coastal upwelling.

Source: NOAA (2)

Offshore wind turbines work by converting kinetic wind energy into electricity. There is, therefore, an inherent loss of kinetic wind energy from the ecosystem due to the operation of wind turbines. Because of that, some have worried about offshore wind leading to a loss of coastal wind, thereby disrupting ocean upwelling and other ocean-atmospheric dynamics. Early modeling (3) suggests that the loss of wind energy due to offshore wind could produce an approximately 5% loss of wind strength. Additional research is currently being conducted to better understand these impacts and potential ways to avoid, minimize, and mitigate them.


Watch this video of Dr. Grace Change speaking to the California Coastal Commission about her research on offshore wind energy and upwelling (4).

References​

  1. Quan, J. (2021, March 22). What is Coastal Upwelling and Why is it Important? U.C. Davis Coastal and Marine Sciences Institute. https://marinescience.ucdavis.edu/blog/upwelling 

  2. National Oceanic & Atmospheric Administration Fisheries. (n.d.). What is upwelling? https://oceanservice.noaa.gov/facts/upwelling.html 

  3. Raghukumar, K., Nelson, T., Chang, G., et al. (2024, February 27). A Numerical Modeling Framework to Evaluate Effects of Offshore Wind Farms on California’s Coastal Upwelling Ecosystem. California Energy Commission. www.energy.ca.gov/publications/2024/numerical-modeling-framework-evaluate-effects-offshore-wind-farms-californias 

  4. California Coastal Commission. (2023, May 11). Informational Briefing on Offshore Wind. https://drive.google.com/file/d/1TlBS-SKP-De2ZXYT8mPWXio3wtUaWfoy/view

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