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DOE OSTI2017

Final Report Feasibility Study for the California Wave Energy Test Center (CalWavesm) - Volume #2 - Appendices #16-17

The California Wave Energy Test Center (CalWave) Feasibility Study project was funded over multiple phases by the Department of Energy to perform an interdisciplinary feasibility assessment to analyze the engineering, permitting, and stakeholder requirements to establish an open water, fully energetic, grid connected, wave energy test center off the coast of California for the purposes of advancing U.S. wave energy research, development, and testing capabilities. Work under this grant included wave energy resource characterization, grid impact and interconnection requirements, port infrastructure and maritime industry capability/suitability to accommodate the industry at research, demonstration and commercial scale, and macro and micro siting considerations. CalWave Phase I performed a macro-siting and down-selection process focusing on two potential test sites in California: Humboldt Bay and Vandenberg Air Force Base. This work resulted in the Vandenberg Air Force Base site being chosen as the most favorable site based on a peer reviewed criteria matrix. CalWave Phase II focused on four siting location alternatives along the Vandenberg Air Force Base coastline and culminated with a final siting down-selection. Key outcomes from this work include completion of preliminary engineering and systems integration work, a robust turnkey cost estimate, shoreside and subsea hazards assessment, storm wave analysis, lessons learned reports from several maritime disciplines, test center benchmarking as compared to existing international test sites, analysis of existing applicable environmental literature, the completion of a preliminary regulatory, permitting and licensing roadmap, robust interaction and engagement with state and federal regulatory agency personnel and local stakeholders, and the population of a Draft Federal Energy Regulatory Commission (FERC) Preliminary Application Document (PAD). Analysis of existing offshore oil and gas infrastructure was also performed to assess the potential value and re-use scenarios of offshore platform infrastructure and associated subsea power cables and shoreside substations. The CalWave project team was well balanced and was comprised of experts from industry, academia, state and federal regulatory agencies. The result of the CalWave feasibility study finds that the CalWave Test Center has the potential to provide the most viable path to commercialization for wave energy in the United States.

16 TIDAL AND WAVE POWER↗
DOE OSTI2017

Idaho National Laboratory’s FY 2016 Greenhouse Gas Report

A greenhouse gas (GHG) inventory is a systematic approach to account for the production and release of certain gases generated by an institution from various emission sources. The gases of interest are those that climate science has identified as related to anthropogenic global climate change. This document presents an inventory of GHGs generated during Fiscal Year (FY) 2016 by Idaho National Laboratory (INL), a Department of Energy (DOE) sponsored entity, located in southeastern Idaho. In recent years, concern has grown about the environmental impact of GHGs. This, together with a desire to decrease harmful environmental impacts, would be enough to encourage the calculation of an inventory of the total GHGs generated at INL. Additionally, INL has a desire to see how its emissions compare with similar institutions, including other DOE national laboratories. Executive Order 13693 requires that federal agencies and institutions document reductions in GHG emissions. INL’s GHG inventory was calculated according to methodologies identified in federal GHG guidance documents using operational control boundaries. It measures emissions generated in three scopes: (1) INL emissions produced directly by stationary or mobile combustion and by fugitive emissions, (2) the share of emissions generated by entities from which INL purchased electrical power, and (3) indirect or shared emissions generated by outsourced activities that benefit INL (occur outside INL’s organizational boundaries, but are a consequence of INL’s activities). This inventory found that INL generated 85,525 metric tons (MT) of CO 2 equivalent (CO 2 e ) emissions during FY 2016. The following conclusions were made from looking at the results of the individual contributors to INL’s FY 2016 GHG inventory: Electricity (including the associated transmission and distribution losses) is the largest contributor to INL’s GHG inventory, with over 50% of the CO 2 e emissions; Other sources with high emissions were employee commuting, mobile combustion (fleet fuels), stationary combustion (facility fuels), business air travel, and waste disposal (fugitive emissions from the onsite landfill); Sources with low emissions were wastewater treatment (onsite and contracted), business ground travel (in personal and rental vehicles), waste disposal (contracted disposal), and fugitive emissions from refrigerants. This report details the methods behind quantifying INL’s GHG inventory and discusses lessons learned on better practices by which information important to tracking GHGs can be tracked and recorded. It is important to note that because this report differentiates between those portions of INL that are managed and operated by Battelle Energy Alliance (BEA) and those managed by other contractors, it includes only the Laboratory activities overseen by BEA. It is assumed that other contractors will provide similar reporting for those activities they manage, where appropriate.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

IAEA Cooperative Research Project (CRP) Status Report

This report provides an end of year summary that reflects the progress and status of United States (U.S.) activities supporting the International Atomic Energy Agency (IAEA) Cooperative Research Project (CRP) effort to develop Modular High Temperature Reactor (HTGR) Safety Design Criteria. These U.S. activities are being managed by the Idaho National Laboratory (INL) on behalf of the U.S. Department of Energy (DOE), and it is noted that this summary reflects progress during the second year of this planned three year activity. This status summary addresses Level 3 milestone M3AT 17IN2001083 in work package AT 17IN200108. U.S. contributions to this CRP effort in FY2017 are reflected in Enclosures A, B, and C, and include (1) a summary description of the modular HTGR’s approach to defense in depth, (2) a summary discussion of how the implementation of the proposed safety design process addresses the key lessons learned from the events at Fukushima, and (3) a brief summary of modular HTGR research and development gap and analysis methods needs.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2017

Catalysis, dynamics and stability of enzymes under extreme conditions

This project led to an unprecedented understanding of how enzymes can catalyze chemical reactions with such high catalytic turnover numbers. This was achieved by a detailed description of the free energy landscape of adenylate kinase using a combination of experimental atomic resolution techniques and computation. In this project, a systematic approach was developed how to characterize free energy landscapes with these biophysical methods. These approaches are directly transferable to other enzymes. In addition, we recreated the evolutionary pathway of enzyme evolution over about 3.5 billion years. The results shed light into how enzymes adapted to the decrease in temperature by increasing their catalytic power at lower temperatures. The data demonstrate fundamental principles of evolution such as active pressure versus passive drift. The adaptation of biocatalyst to extreme conditions such as high or low temperature, pressure (living deep at sea) or high salt was studied. Lessons learned from this project have major implications for catalysis in biotechnology.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Simulation Data Management - Requirements and Design Specification

Simulation Data Management (SDM), the ability to securely organize, archive, and share analysis models and the artifacts used to create them, is a fundamental requirement for modern engineering analysis based on computational simulation. We have worked separately to provide secure, network SDM services to engineers and scientists at our respective laboratories for over a decade. We propose to leverage our experience and lessons learned to help develop and deploy a next-generation SDM service as part of a multi-laboratory team. This service will be portable across multiple sites and platforms, and will be accessible via a range of command-line tools and well-documented APIs. In this document, we’ll review our high-level and low-level requirements for such a system, review one existing system, and briefly discuss our proposed implementation.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗
DOE OSTI2017

Fuel Cell Buses in U.S. Transit Fleets: Current Status 2017

This report, published annually, summarizes the progress of fuel cell electric bus (FCEB) development in the United States and discusses the achievements and challenges of introducing fuel cell propulsion in transit. The report provides a summary of results from evaluations performed by the National Renewable Energy Laboratory. This annual status report combines results from all FCEB demonstrations, tracks the progress of the FCEB industry toward meeting technical targets, documents the lessons learned, and discusses the path forward for commercial viability of fuel cell technology for transit buses. These data and analyses help provide needed information to guide future early-stage research and development. The 2017 summary results primarily focus on the most recent year for each demonstration, from August 2016 through July 2017. The primary results presented in the report are from five demonstrations of two different fuel-cell-dominant bus designs: Zero Emission Bay Area Demonstration Group led by Alameda-Contra Costa Transit District (AC Transit) in California; American Fuel Cell Bus (AFCB) Project at SunLine Transit Agency in California; AFCB Project at the University of California at Irvine; AFCB Project at Orange County Transportation Authority; and AFCB Project at Massachusetts Bay Transportation Authority.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2017

An Overview of the U.S. Better Buildings Initiative as a Model for Other Countries

This report offers a comprehensive overview of the U.S. Better Building Initiative, including the program structure, management and implementation. The report also summarizes lessons learned for a U.S. audience and offers approaches that might be replicated in China and elsewhere.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Production Facility Prototype Blower 1000 Hour Test Results II

Long duration tests of the Aerzen GM 12.4 roots style blower in a closed loop configuration provides valuable data and lessons learned for long-term operation at the Mo-99 production facility. The blower was operated in a closed loop configuration with the flow conditions anticipated in plant operation with a Mo-100 target inline. The additional thermal energy generated from beam heating of the Mo-100 disks were not included in these tests. Five 1000 hour tests have been completed since the first test was performed in January of 2016. All five 1000 hour tests have proven successful in exposing preventable issues related to oil and helium leaks. All blower tests to this date have resulted in stable blower performance and consistency. A summary of the results for each test, including a review of the first and second tests, are included in this report.

42 ENGINEERING↗
DOE OSTI2018

Merging symmetry projection methods with coupled cluster theory: Lessons from the Lipkin model Hamiltonian

Coupled cluster and symmetry projected Hartree-Fock are two central paradigms in electronic structure theory. However, they are very different. Single reference coupled cluster is highly successful for treating weakly correlated systems, but fails under strong correlation unless one sacrifices good quantum numbers and works with broken-symmetry wave functions, which is unphysical for finite systems. Symmetry projection is effective for the treatment of strong correlation at the mean-field level through multireference non-orthogonal configuration interaction wavefunctions, but unlike coupled cluster, it is neither size extensive nor ideal for treating dynamic correlation. We here examine different scenarios for merging these two dissimilar theories. We carry out this exercise over the integrable Lipkin model Hamiltonian, which despite its simplicity, encompasses non-trivial physics for degenerate systems and can be solved via diagonalization for a very large number of particles. We show how symmetry projection and coupled cluster doubles individually fail in different correlation limits, whereas models that merge these two theories are highly successful over the entire phase diagram. Despite the simplicity of the Lipkin Hamiltonian, the lessons learned in this work will be useful for building an ab initio symmetry projected coupled cluster theory that we expect to be accurate in the weakly and strongly correlated limits, as well as the recoupling regime.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

TRU Corp Board Slides

This report presents LANL news, TRU waste certification, Plans to reduce inventory, and Lessons learned.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Final Technical Report

In September 2010, RTI and the DOE/NETL signed a cooperative agreement (DE-FE000489) to design, build, and operate a pre-commercial syngas cleaning system that would capture up to 90% of the CO 2 in the syngas slipstream, and demonstrate the ability to reduce syngas contaminants to meet DOE’s specifications for chemical production application. This pre-commercial syngas cleaning system is operated at Tampa Electric Company’s (TEC) 250-MWe integrated gasification combined cycle (IGCC) plant at Polk Power Station (PPS), located near Tampa, Florida. The syngas cleaning system consists of the following units: Warm Gas Desulfurization Process (WDP) - this unit processes a syngas flow equivalent of 50 MWe of power (50 MWe equivalent corresponds to about 2.0 MM scfh of syngas on dry basis) to produce a desulfurized syngas with a total sulfur (H 2 S+COS) concentration ~ 10 ppmv. Water Gas Shift (WGS) Reactor - this unit converts sufficient CO into CO 2 to enable 90% capture of the CO 2 in the syngas slipstream. This reactor uses conventional commercial shift catalyst technologies. Low Temperature Gas Cooling (LTGC) - this unit cools the syngas for the low temperature activated MDEA process and separates any condensed water. Activated MDEA Process (aMDEA) - this unit employs a non-selective separation for the CO 2 and H 2 S present in the raw syngas stream. Because of the selective sulfur removal by the upstream WDP unit, the CO 2 capture target of 90% CO 2 can be achieved with the added benefit that total sulfur concentration in the CO 2 product is < 100 ppmv. An additional advantage of the activated MDEA process is that the non-selective sulfur removal from the treated syngas reduces sulfur in the treated gas to very low sub-ppmv concentrations, which are required for chemical production applications. Testing to date of this pre-commercial syngas cleaning system has shown that the technology has great potential to provide clean syngas from coal and petcoke-based gasification at increased efficiency and at significantly lower capital and operating costs than conventional syngas cleanup technologies. However, before the technology can be deemed ready for scale-up to a full commercial-scale demonstration, additional R&D testing is needed at the site to address the following critical technical risks: WDP sorbent stability and performance; Impact of WDP on downstream cleanup and conversion steps; Metallurgy and refractory; Syngas cleanup performance and controllability; Carbon capture performance and additional syngas cleanup The proposed plan to acquire this additional R&D data involves: Operation of the units to achieve an additional 3,000 hours of operation of the system within the performance period, with a target of achieving 1,000 hours of those hours via continuous operation of the entire integrated pre-commercial demonstration system; Rapid turnaround of repairs and/or modifications required as necessary to return any specific unit to operating status with documentation and lessons learned to support technology maturation, and; Proactive performance of maintenance activities during any unplanned outages and if possible while operating.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

California-Specific Power-to-Hydrogen and Power-to-Gas Business Case Evaluation

Flexible operation of electrolysis systems represents an opportunity to reduce the cost of hydrogen for a variety of end-uses while also supporting grid operations and thereby enabling greater renewable penetration. California is an ideal location to realize that value on account of growing renewable capacity and markets for hydrogen as a fuel cell electric vehicle (FCEV) fuel, refineries, and other end-uses. Shifting the production of hydrogen to avoid high cost electricity and participation in utility and system operator markets along with installing renewable generation to avoid utility charges and increase revenue from the Low Carbon Fuel Standard (LCFS) program can result in around $2.5/kg (21%) reduction in the production and delivery cost of hydrogen from electrolysis. This reduction can be achieved without impacting the consumers of hydrogen. Additionally, future strategies for reducing hydrogen cost were explored and include lower cost of capital, participation in the Renewable Fuel Standard program, capital cost reduction, and increased LCFS value. Each must be achieved independently and could each contribute to further reductions. Using the assumptions in this study found a 29% reduction in cost if all future strategies are realized. Flexible hydrogen production can simultaneously improve the performance and decarbonize multiple energy sectors. The lessons learned from this study should be used to understand near-term cost drivers and to support longer-term research activities to further improve cost effectiveness of grid integrated electrolysis systems.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2018

Power Take-off System for Marine Renewable Devices

The Power Take-off (PTO) System for Marine Renewable Devices (Project) envisioned the design, manufacture and testing of a generator that would ultimately be suitable for fully flooded seawater operation. This would require a generator design and bearing system capable of operating in the presence of seawater without corrosion. The original generator concept design focused on a switched reluctance electromagnetic design for the generator with the understanding that the switched reluctance design would be more robust and tolerant of a seawater medium. A trade study was conducted to prove that hypothesis, but the results of the study indicated that there was no benefit to adopting a switched reluctance design over a more conventional synchronous permanent magnet design. In addition, the novelty of the switched reluctance design added more technical risk to the Project than was warranted. ORPC’s cost of energy analyses pointed to reliability as being the most critical factor for achieving Project systems performance advancement (SPA) metrics. Consequently, the choice of a permanent magnet (PM) machine design over a potentially less reliable switched reluctance design was necessary to achieve the Project results. As a result, ORPC determined that a PM design was a more appropriate design to achieve the Project goals and ORPC selected a highly qualified PM generator firm for the design, manufacture and factory testing of the generator. The factory acceptance test (FAT) of the generator took place on March 20-22, 2017 and all tests were successfully passed. Developing a design for a driveline as part of the PTO system required a full understanding of the loads and operating conditions expected. Detailed analyses for developing turbine loads and subsequent definition of bearing specifications were performed using various analytical methods. Two candidate bearing designs were proposed as part of the Project. After initial design work had been completed, ORPC designed a representative full-scale driveline to validate the detailed design of the advanced driveline components. Full-scale components were manufactured, instrumented and tested, simulating actual system parameters. This full-scale bearing test was conducted at the University of Maine Advanced Structures and Composites Laboratory. The purpose of this test was to characterize the frictional losses associated with bearings and test the suitability and functionality of some commercially available shaft couplings and expansion bushings in cross-flow turbine drivelines. In parallel with component testing and dynamometer testing of the PTO system, ORPC performed design work to demonstrate how the advanced PTO system will be integrated with all ORPC turbine generator units (TGUs). The work would focus primarily on the TidGen® TGU and assess how the advanced PTO would be integrated into TidGen® 001 or other units, then field-deployed and tested in an open water environment under actual operational conditions. In addition to the benefits provided to the MHK industry in general, and ORPC in particular, the Project provided benefits to the general public, including the following: • Increased general awareness of the potential for generation of electricity from ocean energy resources • Demonstrated continuing advancements in the commercialization of MHK technologies, making them more likely to contribute to the electricity generation supply in America in the coming years • Continued awareness of the local economic benefits from the MHK industry through job creation and local spending • Confirmation of a path to improvements in availability, power-to-weight ratio (PWR) and reduction in levelized cost of energy (LCOE). All Project tasks were completed, and the Project objectives were accomplished. All project milestones and deliverables were met. The designs, methodologies, practices, testing, data, analysis and lessons learned from the Project are a step forward in the development of the U.S. MHK industry and provide a sound basis for ultimate commercialization of ORPC’s power systems. Based on the what was learned and demonstrated during the Project, ORPC has determined that the ORPC power systems have the potential of accelerating the commercialization of tidal and ocean current MHK power systems.

16 TIDAL AND WAVE POWER↗
DOE OSTI2018

American Recovery and Reinvestment Act of 2009: Final Report on Customer Acceptance, Retention, and Response to Time-Based Rates from Consumer Behavior Studies

Time-based rate programs, enabled by utility investments in advanced metering infrastructure (AMI), are increasingly being considered by utilities as tools to reduce peak demand and enable customers to better manage consumption and costs. Under the Smart Grid Investment Grant Program (SGIG), the U.S. Department of Energy (DOE) partnered with several electric utilities to conduct consumer behavior studies (CBS). The goals involved applying randomized and controlled experimental designs for estimating customer responses more precisely and credibly to advance understanding of time-based rates and customer systems, and provide new information for improving program designs, implementation strategies, and evaluations. The intent was to produce more robust and credible analysis of impacts, costs, benefits, and lessons learned and assist utility and regulatory decision makers in evaluating investment opportunities involving time-based rates.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2018

Reducing Energy Burden with Solar: Colorado's Strategy and Roadmap for States

The Colorado Energy Office (CEO) recently implemented a multi-pronged strategy to reduce energy burden for low-income (LI) Colorado residents through the deployment of solar electricity generation. Due to these efforts, approximately 20 MW of photovoltaic (PV) solar may be deployed in Colorado by the end of 2019 specifically for low-income households. Relying on interviews with ten subject-matter experts and other research, this report outlines the details of the CEO strategy including why the agency pursued this strategy, how it was carried out, and lessons learned from implementation. Though CEO's strategy is unique and tailored to the needs of Colorado, it is possible that other states might learn from CEO's experiences when designing their own LI strategies. As a result, the report concludes by outlining six primary steps for designing a comprehensive low-income solar strategy.

14 SOLAR ENERGY↗
DOE OSTI2018

Low-Income Community Solar: Utility Return Considerations for Electric Cooperatives

The objective of this short report is to identify project structures that make low-income community solar projects more cost-effective, replicable, and scalable, for electric cooperative and municipal utilities. This report explores the tradeoffs between providing energy bill savings for low-income subscribers and utility project returns, as well as some of the key lessons learned from existing successful low-income community solar pilot projects.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2018

Next-Generation Performance-Based Regulation. Volume 1: Introduction - Global Lessons for Success; Volume 2: Primer - Essential Elements of Design and Implementation; Volume 3: Innovative Examples from Around the World

Performance-based regulations (PBRs) provide a regulatory framework to connect goals, targets, and measures to utility performance or executive compensation. Well-designed PBRs provide incentives for utility performance, benefiting consumers and utility owners alike. This report considers the role of both PBRs and more discrete performance incentive mechanisms (PIMs) in 21st century power sector transformation. Innovative technologies are transforming the way electricity is generated, delivered, and consumed. PBRs have the potential to realign utility, investor, and consumer incentives and mitigate emerging challenges to the utility business model, renewable integration, and even cyber security.The goals of PBRs in the form of multi-year rate plans are in many respects the same in terms of providing reasonably priced and reliable service to customers. However, today's technologies have changed, and there is more emphasis on clean energy. Thus, the pathways and the potential outcomes are different than they were in the 20th century when centralized generator stations and large infrastructure additions dominated the utility landscape. Given unprecedented changes underway in the electricity sector, PBRs - by specifying expectations of utility performance and outcomes for consumers, while staying agnostic to the exact means of delivery - constitute a form of prescient regulation that harnesses disruption. PBRs are one tool in a broader toolbox in the transition toward flexible regulatory and market structures that rewards utilities that adapt or evolve in reaction to market and technology change. PBRs and PIMs have great value for the electric industry when designed well and can be applied to many different situations. How exactly PBR mechanisms are most effectively enacted will vary based on the utility ownership model, institutional arrangements, and a variety of other local factors. PBRs should be tailored to the needs and goals of each jurisdiction, and perhaps each utility, to most effectively achieve the needs of a 21st century power grid in that jurisdiction. Presented in three volumes, this report highlights the lessons learned from their evolving history, explores essential elements of their design and implementation as well as considerations for how they may be best applied, and examines leading examples of PBRs from the United Kingdom, New York, Denmark, Mexico, and South Africa. The full report, 'Next-Generation Performance Based Regulation - Emphasizing Utility Performance to Unleash Power Sector Innovation,' published in September 2017, can be accessed at https://www.nrel.gov/docs/fy17osti/68512.pdf.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2018

Marine Mammal Behavioral Response to Tidal Turbine Sound

The sound emitted by tidal turbines overlaps with the generalized hearing ranges for marine mammals and may, consequently, affect marine mammal behavior. Because of the strong environmental protections for marine mammals, these effects are of interest to resource agencies and project developers. The primary goal of this project is to improve the understanding of how sound emitted by tidal turbines may affect marine mammal behavior, with the intent that such understanding may allow this environmental risk to be “retired” for initial demonstrations and arrays. A secondary project goal is to evaluate the efficacy of marine mammal observations from a shore-based vantage point as a method to detect change as a consequence of marine energy stressors. Three, two-week trials were conducted across spring, summer and autumn of 2017 during which vantage-point observations of marine mammals were made from land. We refer to these two-week periods as ‘trials’ as they represent different periods of field data collection. These observations consisted of scan samples every 10 minutes with a set of binoculars and a DSLR camera. When pinnipeds were sighted, still images were taken. When harbor porpoise were sighted, focal follows using video were initiated. These data were later analyzed to estimate the location of animals sighted using photogrammetric techniques. For approximately half of each trial period, a boat was moored in the study area from which an underwater projector was used to play back tidal turbine sounds at a broadband source level of 158 dB re µPa @ 1 m. The other half of each trial period had no playbacks and was used as a control period. During the control and playback periods, ancillary data were collected in the study area near the sea floor (ambient noise, tidal velocity, and porpoise clicks) while weather and vessel tracks were recorded near the vantage-point station. Harbor seals did not show a significant response to the simulated turbine noise, nor did harbor porpoise change their closest point of approach or change the direction/deviation of the paths during periods when the playback was occurring. While porpoise sightings and porpoise acoustic detections were significantly reduced during playback periods in the first two trials, the number of detections during the playback periods increased during the third trial. Similarly, the calculated distance from porpoises to the playback location suggests that harbor porpoises avoided an area around the playback location of approximately 300 m during Trial 1, which decreased to approximately 100 m in Trial 2, and disappeared in Trial 3. This could be an indication of habituation or increased tolerance, either to the playback sound or the vessel presence. Our finding of no significant effect of turbine noise on harbor seals contrast with the findings in a previous study by Hastie et al. (2017) conducted in United Kingdom waters. However, due to substantive differences in source levels and propagation loss, seals in our study would need to have been within 10 m of the playback location to experience similar received levels to those in the Hastie et al. study. Consequently, the two studies may actually be in agreement. Our findings of significant effect of turbine noise on harbor porpoise are in line with previous studies suggesting the harbor porpoise are sensitive to noise. However, we note that, due to cost and logistical constraints, the playback vessel was only mooring during the playback periods. Consequently, we cannot definitively ascribe the changes in porpoise behavior to the simulated turbine noise, playback vessel presence, or a combination of both factors. This methodological limitation and other lessons learned are discussed to benefit future studies that explore the effects of acoustic stressors on marine mammals.

16 TIDAL AND WAVE POWER↗