Seabirds in 3D: A Framework to Evaluate Collision Vulnerability with Future Offshore Wind Developments [Final Report]

Wallach, E.; Chamberlin, C.; Jacobson, A.; Schneider, S.; Bernstein, S.; Trush, S.; Ainley, D.; Terrill, S.; Kramer, S. (2025). Seabirds in 3D: A Framework to Evaluate Collision Vulnerability with Future Offshore Wind Developments [Final Report]. Report by Schatz Energy Research Center. Report for California Energy Commission.

@techreport{Wallach-2025-2083170,
author = {Wallach, E and Chamberlin, C and Jacobson, A and Schneider, S and Bernstein, S and Trush, S and Ainley, D and Terrill, S and Kramer, S},
title = {Seabirds in 3D: A Framework to Evaluate Collision Vulnerability with Future Offshore Wind Developments [Final Report]},
institution = {Schatz Energy Research Center},
year = {2025},
month = {apr},
address = {Humboldt, CA, USA},
url = {https://schatzcenter.org/2025/04/seabirdsin3d-finalreport/},
keywords = {Wind Energy, Floating Offshore Wind, Collision, Birds, Seabirds},
}

Export Citation to BibTex

TY - RPRT
TI - Seabirds in 3D: A Framework to Evaluate Collision Vulnerability with Future Offshore Wind Developments [Final Report]
AU - Wallach, E
AU - Chamberlin, C
AU - Jacobson, A
AU - Schneider, S
AU - Bernstein, S
AU - Trush, S
AU - Ainley, D
AU - Terrill, S
AU - Kramer, S
AB - California aims to decarbonize electricity delivered to customers in the state, with a goal ensuring that 100% of electricity sales are from renewable sources and zero-carbon resources by 2045. Offshore wind is expected to play an important role in reaching this goal due to the strong and reliable winds offshore California. Doing so while minimizing impacts to biodiversity is also a priority for the state and many stakeholders. This study evaluates the potential tradeoffs between the collision vulnerability of 44 types of seabirds and offshore wind power generation along California's coast. Using a multi-objective optimization framework, seabird densities at heights where they are vulnerable to colliding with rotating turbine blades and anticipated energy production were assessed, with a goal of highlighting regions that minimize seabird exposure while ensuring viable power generation. The results indicate that there is a diversity and abundance of seabirds across the study area, but most are predicted to remain within 10 meters of the sea surface and are therefore expected to be most concentrated below rotor-swept heights. Furthermore, seabirds are most dense nearshore and to the south, while the best wind resources are generally offshore and to the north. Long-term datasets suggest about 8 percent of the seabird community is likely to be present at heights exceeding 10 meters above the sea surface, a height that serves as a conservative proxy for entering rotor swept heights. Above 10 meters, seabirds are expected to be dominated by the seasonally abundant sooty shearwater (a dynamic soaring species) and various gull species. These findings can guide offshore wind site selection to ensure California's renewable energy development considers seabird populations, focusing on those that are most likely to be exposed. This report provides novel estimates of seabird density that incorporate a third, vertical, dimension to the more traditional two-dimensional predictions and represents rates of presence at heights that would expose seabirds to collision with rotating turbine blades. Expected exposure rates are much greater than, and distinct from, expected collision rates, the first being the focus of this study and the second requiring additional, site-specific data on prevailing wind and seabird flight directionality as well as species-specific behavioral responses to the presence of wind turbines (avoidance and attraction rates), which will be the focus of future studies.Related Resources:Seabirds in 3D: A Framework to Evaluate Collision Vulnerability with Future Offshore Wind Developments - Interim Project Report #2: Assessing Tradeoffs between Seabird Density at Collision Risk Height and Wind Facility Performance (Wallach et al. 2025)Seabirds in 3D: A Framework to Evaluate Collision Vulnerability with Future Offshore Wind Developments - Interim Project Report #1: Estimating Collision Vulnerability of the Seabird Community Across a Segment of the California Current System (Schneider et al. 2024)Seabirds in 3D: A Framework to Evaluate Collision Vulnerability with Future Offshore Wind Developments (2024 Webinar)
CY - Humboldt, CA, USA
DA - 2025/04//
PY - 2025
SP - 78
PB - Schatz Energy Research Center
UR - https://schatzcenter.org/2025/04/seabirdsin3d-finalreport/
LA - English
KW - Wind Energy
KW - Floating Offshore Wind
KW - Collision
KW - Birds
KW - Seabirds
ER -

Export Citation to RIS

Abstract

California aims to decarbonize electricity delivered to customers in the state, with a goal ensuring that 100% of electricity sales are from renewable sources and zero-carbon resources by 2045. Offshore wind is expected to play an important role in reaching this goal due to the strong and reliable winds offshore California. Doing so while minimizing impacts to biodiversity is also a priority for the state and many stakeholders. This study evaluates the potential tradeoffs between the collision vulnerability of 44 types of seabirds and offshore wind power generation along California's coast. Using a multi-objective optimization framework, seabird densities at heights where they are vulnerable to colliding with rotating turbine blades and anticipated energy production were assessed, with a goal of highlighting regions that minimize seabird exposure while ensuring viable power generation. The results indicate that there is a diversity and abundance of seabirds across the study area, but most are predicted to remain within 10 meters of the sea surface and are therefore expected to be most concentrated below rotor-swept heights. Furthermore, seabirds are most dense nearshore and to the south, while the best wind resources are generally offshore and to the north. Long-term datasets suggest about 8 percent of the seabird community is likely to be present at heights exceeding 10 meters above the sea surface, a height that serves as a conservative proxy for entering rotor swept heights. Above 10 meters, seabirds are expected to be dominated by the seasonally abundant sooty shearwater (a dynamic soaring species) and various gull species. These findings can guide offshore wind site selection to ensure California's renewable energy development considers seabird populations, focusing on those that are most likely to be exposed. This report provides novel estimates of seabird density that incorporate a third, vertical, dimension to the more traditional two-dimensional predictions and represents rates of presence at heights that would expose seabirds to collision with rotating turbine blades. Expected exposure rates are much greater than, and distinct from, expected collision rates, the first being the focus of this study and the second requiring additional, site-specific data on prevailing wind and seabird flight directionality as well as species-specific behavioral responses to the presence of wind turbines (avoidance and attraction rates), which will be the focus of future studies.

Related Resources: