Chapter 1
Introduction

The Nantucket Shoals region off the coast of Massachusetts and Rhode Island is being targeted for offshore wind energy development to advance clean energy and decarbonization goals. Nantucket Shoals is a key foraging area for the critically endangered North Atlantic right whale (Eubalaena glacialis), and some scientists are concerned about whether disturbances in hydrodynamics associated with wind farms could influence the distribution and aggregation of Calanus finmarchicus, a foundational species of zooplankton and the whales’ major prey. Right whales require high densities of these zooplankton for efficient foraging. At the same time, the oceanography of Nantucket Shoals is highly complex and continually evolving, leading to significant uncertainties in the understanding of the region’s physical and biological processes, the interactions among them, and how wind energy development might impact them.

A 2024 consensus report by the National Academies of Sciences, Engineering, and Medicine (NASEM), Potential Hydrodynamic Impacts of Offshore Wind Energy on Nantucket Shoals Regional Ecology: An Evaluation from Wind to Whales (NASEM, 2024), examined the potential for offshore wind farms in the Nantucket Shoals region to affect oceanic physical processes and in turn impact ecosystem dynamics including zooplankton productivity and aggregations relevant to right whale foraging and population viability. Among other recommendations, the report outlined the need for observational and modeling efforts to fill knowledge gaps and inform decision-making regarding future wind energy development in the region. To delve further into how field monitoring programs might best meet these needs, the study’s sponsor, the Bureau of Ocean Energy Management (BOEM), requested that the study committee organize a follow-on workshop exploring observational needs and identifying components of a field monitoring program that could help to advance models for elucidating the potential effects of wind energy development on Nantucket Shoals ecology. The workshop Field Monitoring Program to Evaluate Hydrodynamic Impacts of Offshore Wind Energy on Nantucket Shoals Regional Ecology was held July 9–10, 2024, in Washington, DC, and brought members of the

study committee together with additional participants from academia, government, and the offshore wind industry. Over the course of the 2-day workshop, participants engaged in a series of breakout sessions and full-group discussions to exchange information about current and planned research, monitoring, and modeling efforts; discuss key questions for research programs going forward; and examine challenges and opportunities involved in designing field monitoring programs to effectively and efficiently address these questions. The workshop agenda and participant list are provided in Appendix A. This proceedings of a workshop summarizes the workshop presentations and discussions based on slides, transcripts, and recordings from the event; it does not reflect the consensus views of workshop participants or the National Academies.

Eileen Hofmann, Old Dominion University, and Thomas Kilpatrick, BOEM, offered opening remarks to frame the workshop’s goals and focus. Hofmann, who served as chair of the National Academies Committee on Evaluation of Hydrodynamic Modeling and Implications for Offshore Wind Development: Nantucket Shoals, described key findings and recommendations from the committee’s 2024 report. One key message that emerged from the committee’s deliberations is that significant uncertainties exist in assessing how wind energy areas (WEAs) in the Nantucket Shoals region will impact hydrodynamics, zooplankton, and North Atlantic right whales at multiple scales. In addition, the committee found that the significant natural and anthropogenic variability in this complex system suggests that any hydrodynamic or biological impacts of WEAs will be difficult to isolate and differentiate from changes arising from other sources. Finally, the committee emphasized that building responsible offshore wind infrastructure requires coordinated regional efforts to understand and identify hydrodynamic and ecological effects, including case studies of existing WEAs and a range of models at the appropriate scales to capture the region’s physical and ecological complexity.

To ensure that any Nantucket Shoals WEA is planned, constructed, and developed in an environmentally responsible way, BOEM asked the National Academies to consider potential impacts on oceanic physical processes and regional ecosystems during all phases of wind energy development and at the turbine, WEA, and regional scales (see Figure 1). At the turbine scale (roughly 1 meter to 1 kilometer), Hofmann noted that wind wakes increase turbulence and decrease downstream wind, ocean wakes increase downflow turbulence, and the turbine itself disrupts water circulation (see Figure 2). At the WEA scale (ranging from 1 kilometer to hundreds of kilometers), there can be effects on ocean current speeds, ocean surface wind speeds, water stratification, and density. Impacts at the regional scale are more challenging to quantify because of the level of natural variability at this scale, Hofmann noted. Although models have been developed that are relevant to understanding impacts at each of these scales, she said that no single model is sufficient for capturing the full picture. She added that most of what is known about WEA effects is from observation and modeling studies (i.e., Carpenter et al., 2016; Cazenave et al., 2016; Daewel et al., 2022; van der Molen et al., 2014) of North Sea installations, and it is unclear how applicable they are to Nantucket Shoals.

In addition, most studies (e.g., the review by Stevens and Meneveau, 2017) have focused on atmospheric effects at “hub height,” the top of the turbine, and not effects at the ocean surface.

Several of the report’s major recommendations speak to the need for further research and modeling. Specifically, the report recommended that BOEM, the National Oceanic and Atmospheric Administration (NOAA), and others support efforts to advance observational studies to isolate, quantify, and characterize hydrodynamic effects; validate how well existing models simulate relevant hydrodynamic processes at turbine, wind farm, and/or regional scales; collect oceanographic and ecological observations through a robust integrated monitoring program before and during all phases of wind energy development; and require oceanographic and ecological modeling across these same phases. This information will be critical to crafting policies that protect right whales’ ability to forage and improve predictions of ecological impacts at other wind development sites.

Building on these study outcomes, the workshop provided a forum for discussing options for designing a field monitoring program to support implementation of the report recommendations. Commenting that BOEM is seeking to pinpoint what should be monitored and not necessarily who should perform the monitoring, Kilpatrick provided additional context about the workshop goals. While there have been relatively few studies about WEA effects, several BOEM-funded studies are helping to generate data to inform environmental reviews (Chen et al., 2016; Johnson et al., 2021). Kilpatrick noted that some of the concerns and questions raised in the context of Nantucket Shoals wind energy development are not unique to Nantucket Shoals. Studies and workshops focused on the potential ecological impacts of wind energy development along the Pacific coastline can offer useful lessons on the importance of surface wind (in addition to hub height measurements), the utility of hydrodynamic models, opportunities associated with glider deployments, and remaining uncertainties around modeling and monitoring impacts at multiple scales.

Kilpatrick articulated several aims of the workshop. He said that the primary focus should be on elucidating specific and feasible field monitoring strategies that can be implemented through future research solicitations. For these efforts to be successful, he said, it will be important to determine the sources of model uncertainties and to establish how uncertainties might impact the interpretation of observational results. He added that it would also be useful to better understand where existing observation systems may be sufficient and where additional sensors or sampling approaches might be needed. To elucidate how WEAs affect hydrodynamics and marine biology, especially zooplankton, he said, there is an urgent need to identify what should be measured, how it should be measured, and what models can also add to the knowledge base.

To examine these issues, the workshop was organized into two main parts: one focused on examples of observational needs and one focused on components of a field monitoring program. For each part, attendees divided into groups for focused discussions around potential needs and opportunities at both the turbine and WEA scales. These breakout discussions and the subsequent full-group discussions that expanded on and synthesized participants’ responses to each topic are summarized in Chapters 2 and 3 of this proceedings. In addition, several participants shared

ongoing and planned data collection activities in and around Nantucket Shoals and attendees discussed potential data-sharing and partnership opportunities to increase the efficiency and impact of monitoring activities across the region. These discussions and participants’ closing reflections on key areas of emphasis for field monitoring programs are summarized in the final section of this proceedings.

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