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.

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).

In November 2024, BOEM published this flyer (5) with more information regarding ongoing research into upwelling off of California's coast.

In 2021, Ocean Protection Council released An Assessment of the Cumulative Impacts of Floating Offshore Wind Farms (6). A report that compares upwelling effects resulting from simulated wind turbines offshore in Morro Bay, Diablo Canyon, and Humboldt Bay. Their metrics show the reductions in Humboldt Bay through upwelled nutrient supply are significantly smaller in comparison.

 Click here to view a presentation on 'Wind-Driven Coastal Upwelling and the Marine Ecosystem Response,' from Oregon State Professor of Oceanographer, Jack Barth, held in January 2020.

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

5. Bureau of Ocean Energy Management. Upwelling and Offshore Wind: What We  Know https://www.boem.gov/sites/default/files/documents/renewableenergy/stateactivities/Handout_Upwelling%20%26amp%3B%20OSW%20v2%20508C.pdf

6. ​Integral Consulting Inc. (2021, December). An Assessment of the Cumulative Impacts of Floating Offshore Wind Farms. https://opc.ca.gov/webmaster/_media_library/2022/02/C0210404_FinalReport_12312021.pdf