SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The Water Power Technologies Office (WPTO) 2019–2020 Accomplishments Report summarizes some of the significant results from WPTO-supported research across its Hydropower and Marine Energy (formerly the Marine and Hydrokinetics) programs.
This report provides a concise and consolidated overview of the Unites States’ marine energy resources . The results reported herein are primarily based on U.S. Department of Energy (DOE)-funded marine energy resource assessments in the following technology areas: wave, tidal currents, ocean currents, ocean thermal gradients, and river currents. This report also incorporates recent updates and refinements to the U.S. wave and tidal resource assessments performed by the national labs. Many of these refinements were undertaken to address feedback from the National Research Council’s evaluation of the original resource assessments (National Research Council 2013). Further, this report refines the analysis that has been published to date by identifying the marine energy resources available in each U.S. state or region to the extent practical. In short, this report summarizes the best available data on U.S. marine energy resources at the state, regional, and national scales.
This study investigates the uncertainty of wave resource assessments due to sea ice in the nearshore region of Alaska using an innovative approach of combining remotely sensed data and a third-generation phase-averaged wave model. Modeling analysis focused on winter months, when high wave energy is present along with sea ice. This study includes recommendations to improve the accuracy of wave resource assessments and optimize marine and hydrokinetic device siting with consideration of sea-ice effects. Additional recommendations, based on preliminary sea-ice information in Cook Inlet, Alaska, are provided for a trajectory analysis of drifting sea ice and a collision risk assessment of sea ice and tidal turbines. The outcome of this project will provide valuable information about the level of sea-ice impact on the accuracy of wave resource assessments in the Alaska nearshore region, and of sea-ice collision risk with MHK devices and ocean observation systems during winter months when sea ice is present.
Model Predictive Control (MPC) is the best controls framework available to wave energy today. It allows for the maximization of energy yield from a WEC system while respecting various constraints and losses in the system. This type of constrained optimization is a critical capability for the techno-economic optimization of WEC devices and is difficult to do effectively with causal controls frameworks. MPC requires a future prediction of wave excitation forces, requiring wave prediction on a future time horizon of up to 30 seconds. The future horizon required is highly dependent on the WEC and PTO type available. To our knowledge no-one has been able to implement MPC on a WEC device at sea, due to the fact that phase-resolved wave-prediction is not a capability that has been sufficiently developed to date. The key objectives of this project are focused on developing “industry-ready” wave prediction technology building blocks that can be applied to a wide range of different wave energy conversion topologies. Our collaborative work with device developers has demonstrated that the level of improvement attainable for any particular device is heavily dependent on the device and PTO topology chosen. The range of annual average power capture improvements is on the order of 10% to over 100%. However, the important aspect is that we can get within about 10% of theoretical upper limits even when considering errors in the wave prediction and more importantly, we can optimize performance while respecting various constraints such as motion amplitude or peak structural loads. The combination of improved performance while limiting structural loads has a net effect of reducing the levelized cost of energy from these emerging technologies and allows us to design control laws that meet an economic optimum. Efforts under a previous project on controls has focused on developing a set of wave-prediction algorithms that work by leveraging a network of wave sensing measurement buoys that are equipped with real-time telemetry. The present work is focusing primarily on using X-band radar to measure the wave-field around the WEC to predict the future excitation forces on the structure and combining the measurements of these different sources to create improvements in the wave-prediction accuracy.
The goal of this Project was to develop a standards-compliant, fabrication-ready design of Columbia Power Technologies’ (C·Power) next-generation wave energy converter (WEC), the StingRAY H3p. The H3p is a design iteration of C·Power’s StingRAY WEC and is intended for electrical power generation suitable for micro-grids or remote loads. The H3p was designed for grid-connection and at least two years of continuous testing and operation at the proposed PacWave-South (PWS) test site.
Globally, governments, companies, and other organizations have committed to achieving net-zero emissions targets in the coming decades. To achieve decarbonization at the scale and pace required to meet these targets, future energy systems will need renewable energy to serve 100% of the existing direct electricity demand, support additional electrification, and decarbonize the wider economy. An energy cluster offshore (ECO) is a concept that seeks to meet this challenge by integrating and optimizing large-scale renewable electricity generation, storage, and fuel production technologies and pairing them with other complementary uses, such as carbon capture or water desalination. This research project explores the techno-economic feasibility of ECO concepts by taking a holistic view of complex, multidisciplinary hybrid plant designs while considering different configurations and objectives. We will outline the most promising technology combinations and configurations, their functional requirements, and opportunities for optimization.
Explore the source record for details and available documents.
2021 DOE HFTO Annual Merit Review and Peer Evaluation Meeting Poster covering NREL's work reviewing the current state of knowledge as related to marine renewable energy (MRE), hydrogen, and how those two technologies could be integrated for offshore and non-grid applications.
The National Renewable Energy Laboratory's (NREL's) Flatirons Campus features two dynamometers in the Water Power Systems Laboratory that can perform research validation on marine and hydrokinetic energy devices as well as wind turbine systems from 100 watts to 15 kilowatts (kW) in size. These capabilities can also be combined with programmable loads, blue economy (nrel.gov/water/powering-blue- economy.html) application simulators, and microgrid emulators to test an extensive range of system operation and technology integration. The dynamometers replicate realistic operational conditions to assess power take-of systems and advance the technical readiness of innovations.
CalWave / EGI's (Evergreen Innovation) TEAMER (Testing and Expertise for Marine Energy) award: data and post access report for the xWave's Real Time IMU (inertial measurement unit) Optimization for Advanced Controls.
This archive includes data from the University of Washington WASIRF (Washington Air-Sea Interaction Research Facility) flume. WASIRF is a laboratory testing tank at the Northwest National Marine Renewable Energy Center designed to investigate wind-wave-current interactions. It includes test data for simultaneous waves and current generation done at the WASIRF lab. A report included in the archive further details testing methodology. Wave and current data is provided in .dat files.
Software and testing data from the OH Hinsdale Wave lab for DOE-funded project on Co-Design of Marine Energy Converters for Autonomous Underwater Vehicle Docking and Recharging. This project will perform foundational research and testing to accelerate the sector-wide development and deployment of marine energy converters to provide Power-At-Sea. Specifically, we seek to overcome known challenges and knowledge gaps for the successful co-design of coupled Wave Energy Converter (WEC)-Autonomous Underwater Vehicles (AUV) systems; systems designed and tested for WEC array system health and environmental monitoring applications. This project brings together an experienced, multi-institution, and multi-disciplinary team to focus on the co-design of marine energy (ME) technologies and AUV docking systems, including multi-body hydrodynamic modeling, active control, autonomy, and hardware interfaces necessary to enable new WEC-focused understanding, and allow for robust and ubiquitous AUV docking and recharging in real-world conditions.
The data provided is part of a power take off damping optimization study. The power take off damping coefficient was swept from 0 to approximately 7000 N/m/s during a single regular wave test with a real time control of the motor/generator. The generated power from the LUPA (Lab Upgrade Point Absorber) wave energy converter is reported by the motor drive in watts. The csv files in this submission are the corresponding raw time series outputs for each mode of operation of LUPA (one body heave only, two body heave only, and two body six degrees of freedom). Data comes from testing in the Large WaveFlume (LWF) at the O.H. Hinsdale Wave Research Laboratory in Corvallis, OR.
Tidal turbines are one source of marine renewable energy but development of tidal power is hampered by uncertainties in fish-turbine interaction impacts. Current knowledge gaps exist in efforts to quantify risks, as empirical data and modeling studies have characterized components of fish approach and interaction with turbines, but a comprehensive model that quantifies conditional occurrence probabilities of fish approaching and then interacting with a turbine in sequential steps is lacking. We combined empirical acoustic density measurements of Pacific herring ( Clupea pallasii ) and when data limited, published probabilities in an impact probability model that includes approach, entrainment, interactions, and avoidance of fish with axial or cross-flow tidal turbines. Interaction impacts include fish collisions with stationary turbine components, blade strikes by rotating blades, and/or a collision followed by a blade strike. Impact probabilities for collision followed by a blade strike were lowest with estimates ranging from 0.0000242 to 0.0678, and highest for blade strike ranging from 0.000261 to 0.40. Maximum probabilities occurred for a cross-flow turbine at night with no active or passive avoidance. Estimates were lowest when probabilities were conditional on sequential events, and when active and passive avoidance was included for an axial-flow turbine during the day. As expected, conditional probabilities were typically lower than analogous independent events and literature values. Estimating impact probabilities for Pacific herring in Admiralty Inlet, Washington, United States for two device types illustrates utilization of existing data and simultaneously identifies data gaps needed to fully calculate empirical-based probabilities for any site-species combination.
In this article, a new method to control an ocean current turbine (OCT) is examined. The key innovation, inspired by helicopter control, is to use cyclic blade pitch angle variations. Finally, output variance constrained controllers are designed for OCT flight control and their performance is analyzed.
Most marine renewable energy (MRE) technologies are still in their infancy. Many uncertainties remain regarding MRE systems’ impacts on the marine environment and species where they are deployed, which is one of the major hurdles for these systems to be widely adopted at a commercial scale. Currently, the primary technologies to monitor marine animals’ behavior around existing or potential MRE deployment sites are optical and acoustic imaging. However, these methods cannot identify individual animals and thus are less useful in identifying protected species and studying their behavior. Implantable acoustic transmitters with unique identification codes could serve as a complementary technology. To minimize potential bias introduced to the study results, the implanted transmitters must be sufficiently small and light to not affect the animals’ behavior while still having acceptable signal strengths and service life. Recently, we developed a new miniaturized acoustic transmitter that offers a significantly improved signal strength and service life (140 days [projected value] at a 5-s transmission interval) in a smaller and lighter package (0.45 g in the air), compared to the existing technologies. The detection range and detection efficiency of the new transmitter were tested in an actual marine environment and demonstrated a detection range of up to 330 m, a 65% improvement over the existing commercial counterparts operating at similar frequencies. Here, we report the design principles, performance, and manufacturing procedure of the transmitter. Finally, theoretical estimates of the detection range, the actual range, and detection efficiency results from the field testing are presented.
This submission includes System Content Models with data following manufacture for the Verdant Power TriFrame, Gen5 Kinetic Hydropower System (KHPS) Turbines, and Balance of Plant (BOP). The TriFrame installs 3 Gen5 KHPS Turbines. The BOP system controls the turbines and interconnects the TriFrame to shoreline with supervisory control and data acquisition (SCADA).
The Modular RivGen LCOE Content Model contains estimates of levelized cost of energy (LCOE) for three array configurations operating in a theoretical river environment. The LCOE is distinguished by the CapEx, OpEx, and annual energy production and capture for each river environment.