National Renewable Energy Laboratory Researchers Research Articles

Wave Energy Power Take-off Validation with a Hydraulicly Actuated Rotary Dynamometer and a Bi-directional High-power DC Supply

There are many organizations working towards the commercialization of wave energy converter technologies and are advancing their designs through the technology readiness levels (TRLs). A critical step before the field deployment of prototype wave energy converters is the validation of the subsystems and components that are contained in the wave energy converter through laboratory testing and performance characterization. In 2021, the National Renewable Energy Laboratory (NREL) developed and demonstrated a system for testing power takeoffs (PTO) with a low-speed, high-torque dynamometer and a grid-tied high-power DC power source and sink before field deployment. The hydraulic dynamometer allows for the simulation of PTO actuation from wave motion and is capable of a wide range of wave periods and heights which are represented as various speeds and torques from the dynamometer. The high-power bidirectional power supply allows for hardware in the loop and controller in the loop testing to be conducted on WEC power electronics. This presentation was made to describe the methods used by NREL research staff to test all components and sub-systems in the PTO of a novel wave energy converter before field deployment.

Research data infrastructure for high-throughput experimental materials science

SummaryThe High-Throughput Experimental Materials Database (HTEM-DB, htem.nrel.gov) is a repository of inorganic thin-film materials data collected during combinatorial experiments at the National Renewable Energy Laboratory (NREL). This data asset is enabled by NREL's Research Data Infrastructure (RDI), a set of custom data tools that collect, process, and store experimental data and metadata. Here, we describe the experimental data flow from the RDI to the HTEM-DB to illustrate the strategies and best practices currently used for materials data at NREL. Integration of the data tools with experimental instruments establishes a data communication pipeline between experimental researchers and data scientists. This work motivates the creation of similar workflows at other institutions to aggregate valuable data and increase their usefulness for future machine learning studies. In turn, such data-driven studies can greatly accelerate the pace of discovery and design in the materials science domain.

Potential Efficiency Gains from Early Involvement of Steel Fabricators and Erectors: Lessons Learned from the NREL Research Support Facility Project

While the structural steel industry has made commendable progress to improve its efficiency and reduce its environmental impacts over the years, room remains for improvement, particularly in the fabrication and erection of structural steel during construction. The purpose of this research is to determine the potential benefits of including the steel fabricator and erector early in the design phase with respect to increasing the efficiency and thus reducing the environmental impacts of the structural steel construction process. Interviews were performed with the key participants in the National Renewable Energy Laboratory (NREL) Research Support Facility (RSF) project located in Golden, Colorado, United States to collect information in the form of lessons learned. Analysis revealed several benefits that result from leveraging the unique perspective and knowledge of the steel fabricator and erector during the design phase when utilizing them for decisions concerning fastening hardware, types of connections, and erection sequencing. In addition, the steel fabricator and erector may be able to foresee potential conflicts between structural and architectural features. This information supports reduced resource use, identification of cost effective solutions, significant efficiency increases, and a reduction in environmental impacts.

Bioreactor Design Studies for a Hydrogen-Producing Bacterium

Carbon monoxide (CO) can be metabolized by a number of microorganisms along with water to produce hydrogen (H2) and carbon dioxide. National Renewable Energy Laboratory researchers have isolated a number of bacteria that perform this so-called water-gas shift reaction at ambient temperatures. We performed experiments to measure the rate of CO conversion and H2 production in a trickle-bed reactor (TBR). The liquid recirculation rate and the reactor support material both affected the mass transfer coefficient, which controls the overall performance of the reactor. A simple reactor model taken from the literature was used to quantitatively compare the performance of the TBR geometry at two different size scales. Good agreement between the two reactor scales was obtained.

Improved Blade Designs and Manufacturing Processes Reduce the Cost of Wind Energy

One way to reduce the cost of wind energy is to improve the design and manufacturing processes for wind turbine blades to increase their strength and reliability. Because the mechanical properties of the blades determine the loads transmitted to the other components in the turbine, improved blade designs can also increase overall turbine performance. New blade shape designs produced through the U.S. Department of Energy’s (DOE’s) Wind Program have increased wind turbine performance by as much as 30% over designs used just 10 years ago. As wind turbine blades increase in length, the blade weight increases faster than the energy it can produce. To produce blades for larger machines without increasing costs, industry researchers at the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories are investigating new materials like carbon or glass-carbon hybrids, new manufacturing processes that improve fiber alignment and compaction, and new rotor designs. As part of the new design process, NREL researchers conduct tests such as the two-axis fatigue test being conducted on an Enron Wind EW-750 wind turbine blade at the laboratory’s Industrial User Facility. Fatigue tests simulate continuous operating loads to help designers understand blade materials and the structural details of the design. Structural details such as joints, ply drops, and geometric transitions are more difficult to model during early design work and are often the weak link in a blade’s structure.