Wind power has been widely considered in recent years as an available and a clean renewable energy source. The cost of wind energy production is currently the main issue, and increasing the size of wind turbines can reduce wind energy production costs. Hence, megawatt wind turbines are being rapidly developed in recent years. In this paper, an aerodynamic analysis of the NREL 5MW turbine is...

The IEA Wind Task 30 OC4 (Offshore Code Comparison Collaboration Continuation) project was a continuation of the OC3 project of IEA Wind Task 23 Subtask 2, and was initiated due to the strong interest in continuing the work of OC3. The purpose of the project was to perform a benchmarking exercise of offshore wind turbine dynamics codes. OC4 consisted of two phases that were not considered in OC...

As interest for clean renewable electric power technologies grows, a number of parabolic trough power plants of various configurations are being considered for deployment around the globe. It is essential that plant designs be optimized for each specific application. The optimum design must consider the capital cost, operations and maintenance cost, annual generation, financial requirements, an...

The current energy crisis in Nepal clearly indicates that the future energy-demand cannot be met by traditional energy-sources. Community-based micro-hydropower operations are considered to be one of the most feasible options for energy development. However, the power plant capacity factor remains very low due to limited commercial and business opportunities. Generation of hydrogen (H2) from th...

Organic photovoltaic (OPV) cells have recently undergone a rapid increase in power conversion efficiency (PCE) under AM1.5G conditions, as certified by the National Renewable Energy Laboratory (NREL), which jumped from 11.5% October 2017 to 18.2% December 2020. However, NREL PCE of large area OPV modules is still lagging far behind (11.7% July 2020). Additionally, there has been rapidly growing...

In an effort to characterize the dynamics typical of school bus operation, National Renewable Energy Laboratory (NREL) researchers set out to gather in-use duty cycle data from school bus fleets operating across the country. Employing a combination of Isaac Instruments GPS/CAN data loggers in conjunction with existing onboard telemetric systems resulted in the capture of operating information f...

The work described in this report was performed by the National Renewable Energy Laboratory (NREL) and funded by the Office of the Energy Efficiency and Renewable Energy, U.S. Department of Energy (EERE DOE). This project is a joint project with the Pacific Northwest National Laboratory. With the anticipated rapid growth of variable generation such as wind and solar power, there is increasing i...

The work focuses on understanding and characterization of the thin-film vapor-liquid-solid (TFVLS) growth technique as a low-cost process technology for III-V thin film solar cells on metal/glass substrates. In the last review period, we have focused on understanding and controlling the nucleation events of TF-VLS InP. Furthermore, optoelectronic characterization of the grown InP has been perfo...

This research note deals with grid fault-tolerance of a doubly-fed induction generatorbased wind turbine using high-order sliding mode control. Indeed, it is proposed to assess the main and attractive features of high-order sliding modes which are robustness against external disturbances (e.g. grid) and chattering-free behavior (no extra mechanical stress on the drive train). Simulations using ...