Wind Energy Research from the NWTC
Up to Wind Speed is a new quarterly newsletter from NREL's National Wind Technology Center (NWTC). To continue receiving the newsletter, subscribe on the NWTC Web site. Your information is confidential and will be used solely for the distribution of this newsletter.
For more than three decades, research conducted by NREL's Wind Program has helped industry advance wind energy technology, increasing reliability and lowering the cost of energy. As we continue our efforts with the wind industry in 2010, we will keep you up to speed on what's happening in wind energy research and development and provide you with links to the NWTC's recent publications.
In this issue:
In January, the U.S. Department of Energy's National Renewable Energy Laboratory released a major study of the technical, operational, and economic issues facing the integration of large amounts of wind energy into the power system.
The Eastern Wind Integration and Transmission Study (EWITS), the largest study of its kind conducted in the United States to date, evaluates the future operational and integration impacts of up to 30% wind energy penetration into the power system in the study year 2024. The study encompasses the majority of the utilities in the Eastern Interconnection. The study also includes a high-level analysis of transmission needed to deliver the wind energy to load centers and a cursory analysis of carbon pricing impacts. The study consists of three main parts: a wind resource assessment and wind plant siting study, a transmission study, and a wind integration study. The results of the study show that there are no fundamental technical barriers to the integration of 20% wind energy into the electrical system, but transmission planning and system operation policy and market development need to continue to evolve in order for these penetration levels to be achieved.
Read the Executive Summary, Eastern Wind Integration and Transmission Study: Executive Summary and Project Overview (Revised). (2010).
Read the full study, Eastern Wind Integration and Transmission Study (EWITS). (2010).
Upgrading the NWTC's Dynamometer Test Facility: Testing the Next Generation of Wind Turbine Drivetrains
NREL's NWTC Dynamometer Upgrade Project, funded through the American Reinvestment and Recovery Act (ARRA) will equip the NWTC to test the next generation of larger wind turbine drivetrains. As North America's only facility with the ability to test the entire integrated drivetrain system—the gearbox, the generator, the power electronics, and the control system—NWTC's dynamometer will be upgraded from 2.5 MW to 5 MW.
The project, scheduled for completion in 2012, supports commercial wind industry needs to improve the reliability of wind turbine drivetrains and to reduce their cost, for both on and offshore systems. Another important enhancement to the dynamometer's infrastructure will be an improved non-torque loading capability to simulate rotor loads, which are believed to have a significant effect on gearbox life.
The upgraded dynamometer's testing capacity will offer a state-of-the-art facility where U.S. wind industry researchers can test advances in power electronics and drive systems. These lessons learned will enable the NWTC to offer unparalleled research methods for industry advancements.
For more information about the Dyno Upgrade Project, contact Jim Green at 303-384-6913.
Vast offshore wind resources provide the potential to use wind turbines installed offshore to power much of the world. Ensuring that offshore wind turbine installations are cost effective requires the use of a variety of support structure types because offshore sites vary significantly in water depth, soil type, and wind and wave severity. Currently, structural designs include fixed-bottom monopiles, gravity bases, and space-frames—such as tripods and lattice frames ("jackets")—and floating structures. In the case of floating structures, the offshore wind industry faces many new design challenges.
Land-based wind turbines are designed and analyzed using simulation tools (i.e. design codes) capable of predicting the coupled dynamic loads and responses of the system. This analysis relies on the use of aero-servo-elastic codes, which incorporate wind-inflow, aerodynamic (aero), control system (servo), and structural-dynamic (elastic) models in the time domain in a coupled simulation environment.
In recent years, some of these codes have been expanded to include the additional dynamics inherent in offshore installations including incident waves, sea currents, hydrodynamics, and foundation dynamics. The sophistication of these aero-hydro-servo-elastic codes, and the limited data available with which to validate them, underscores the need to verify their accuracy.
NWTC researchers are leading the Offshore Code Comparison Collaboration (OC3), which operates under the IEA's Offshore Wind Energy Technology and Deployment Task 23 and have completed the latest phase of the project. Participants used an assortment of codes, including the NWTC-developed FAST with AeroDyn and HydroDyn code, to model the coupled dynamic response of a 5-MW wind turbine installed on a floating spar buoy with a draft of 320 meters. Code predictions were compared from load-case simulations selected to test different model features. The comparisons have resulted in a greater understanding of offshore floating wind turbine dynamics and modeling techniques, and better knowledge of the validity of various approximations. The lessons learned from this exercise have improved the participants' codes, thus improving the standard of offshore wind turbine modeling.
A paper summarizing the results of this phase of the project will be presented in April at the European Energy Conference (EWEC 2010). Recent presentations, articles, and reports on floating platform modeling and conceptual design and analysis include:
Coming soon: Offshore Code Comparison Collaboration within IEA Wind Task 23: Phase IV Results Regarding Floating Wind Turbine Modeling. Jonkman, J.; Larsen, T.; Hansen, A.; Nygaard, T.; Maus, K.; Karimirad, M.; Gao, Z.; Moan, T.; Fyllin; NREL Report No. 47534.
Coming soon: Definition of the Floating System for Phase IV of OC3.; Jonkman, J. NREL Report No. 47535.
Wind turbine systems are certified to perform within specific wind regimes based on manufacturer specifications. In 2008/2009, the National Wind Technology Center (NWTC) selected and tested four commercially available small wind turbine systems:
Additional information and test results can be found on the Small Wind Turbine Independent Testing Web page.
Testing generally takes about a year to complete and the results are posted on the NWTC web site. The data from these tests may be used by the Small Wind Certification Council (SWCC), a nonprofit organization formed with support from the Department of Energy (DOE), AWEA, state energy offices, and turbine manufacturers to certify small wind turbine systems. The Small Wind Certification Council certifications began working on their certifications in February 2010. Test data could also be submitted to international certification agents as partial qualification for international certification.
For further information on the small wind turbine Independent Testing project, contact Trudy Forsyth at 303-384-6932.
In February, the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) and DOE's Wind and Hydropower Technologies Program announced the selection of four partners to establish small wind Regional Test Centers (RTCs) to conduct tests on small wind turbines to meet national and international standards. These awards provide funding, training, and technical support for each Regional Test Center to conduct testing of two small wind turbines to support the burgeoning U.S. small wind turbine market.
The Regional Test Center project goal is to support the U.S. small wind market by increasing the number of organizations qualified to conduct small wind turbine standards testing and to drive down the cost of this testing. Test results are used by certification bodies, such as the Small Wind Certification Council, to certify small wind turbines for reliability and performance.
Certification testing allows small wind turbine buyers to make informed choices and provides states with the data needed to determine turbine eligibility for incentive programs. These Regional Test Center awards are provided by DOE and NREL in a continuing effort to support the growth of the U.S. small wind turbine market and enable U.S. manufacturers to sell their small wind turbine products abroad.
For more information on Regional Test Centers, see the Regional Test Centers Web page.
The U.S. Department of Energy awarded NREL $7.5 million (over three years) for continued research on marine hydrokinetic energy devices. The research will be conducted by researchers at NREL's NWTC. What do wind and water have in common? Marine hydrokinetic (MHK) energy devices are high-force, low-speed machines, similar to wind turbines that convert the kinetic energy of a moving fluid into electrical energy.
Development of energy through the Earth's largest, most predictable, and renewable resources—its oceans and rivers—requires efficient, high capacity devices designed to maximize performance and reduce capital costs. Research and development efforts that test and validate machine performance are expected to increase investor and regulator confidence and lead to the creation of a U.S. marine energy industry.
The NWTC produces information that can be used by government officials, researchers, members of the wind energy industry, utility engineers and planners, and other industry stakeholders to make informed decisions about the technology and advance the use of wind energy generation.
In addition to dozens of publications including technical reports, subcontract reports, conference papers and other research articles produced each year, there are several publications NWTC produces every year. They include Wind Power Today, the International Energy Agency (IEA) Wind Energy Report and the Wind Powering America (WPA) Activities Summary.
See the following reports:
All of the NWTC publications may be accessed on the Publications page on NREL's NWTC Web site.
Recent NREL Wind Publications