Large Wind Technology
The Wind Program works with industry partners to increase the performance and reliability of large wind technologies while lowering the cost of wind energy. The program's research efforts have helped to increase the average capacity factor (a measure of power plant productivity) from 22% for wind turbines installed before 1998 to 35% for turbines installed between 2004 and 2007. Wind energy costs have been reduced from over 55 cents (current dollars) per kilowatt-hour (kWh) in 1980 to under six cents/kWh today.
To ensure future industry growth, the technology must continue to evolve, building on earlier successes to further improve reliability, increase capacity factors, and reduce costs. This page describes the goal of the program's large wind technology research efforts and highlights some of its recent projects.
The program's goal is to reduce the cost of electricity produced by large land-based wind systems in Class 4 winds (15.7-16.8 miles per hour) to 3.6 cents/kWh by 2012, from a baseline of 5-8 cents/kWh.
Research Project Highlights
These are some of the key research project highlights from the program's large wind technology research.
During the past two decades, the program has worked with industry to develop a number of prototype technologies, many of which have become commercially viable products. One example is the GE Wind Energy 1.5-megawatt (MW) wind turbine. Since the early 1990s, the program worked with GE and its predecessors to test components such as blades, generators, and control systems on generations of turbine designs that led to GE's 1.5-MW model. As of May 2009, more than 12,000 of these turbines had been installed in 19 countries.
Another project demonstrating commercial success is the 2.5-MW Liberty wind turbine manufactured by Clipper Windpower. Clipper produced a prototype of its 2.5-MW Liberty turbine in 2005 after only three years of cooperative research and development work with the program. Clipper installed more than 200 of these 2.5-MW turbines in 2008.
The program works with industry partners to improve the performance and reliability of system components. Knight and Carver's Wind Blade Division in National City, California, worked with researchers at the Department of Energy's Sandia National Laboratories to develop an innovative wind turbine blade that the company expects to increase energy capture by 5% to 10%. The most distinctive characteristic of the Sweep Twist Adaptive Rotor (STAR) blade is a gently curved tip, which, unlike the vast majority of blades in use, is specially designed to take maximum advantage of all wind speeds, including slower speeds.
To support the development of more reliable gearboxes, the program has worked with several companies to design and test innovative drivetrain concepts. Clipper's Liberty wind turbine incorporates a highly innovative multiple-drive path gearbox that feeds four advanced permanent-magnet generators. Global Energy Concepts (GEC) fabricated a 1.5-MW, single-stage drivetrain with a planetary gearbox and a medium-speed (190 rpm), permanent-magnet generator that shows potential for reducing tower-head weight and drivetrain costs. Northern Power Systems constructed a permanent-magnet generator with a novel power converter to allow variable-speed operation. The Northern Power Systems converter was chosen by the American Wind Energy Association for its 2006 Technical Achievement Award.
Utility-Scale Research Turbine
In 2009, the program installed a 1.5-MW wind turbine at the National Wind Technology Center in Boulder, Colorado. This turbine is the first large-scale wind turbine fully owned by DOE and will serve as a platform for research projects aimed at improving the performance of wind technology and lowering the costs of wind energy. The 1.5-MW turbine, manufactured by GE and informally known as the "DOE 1.5," will generate power for facilities at the Center and will also feed electricity back into the local grid. The turbine will be heavily instrumented to further research in power performance testing, turbine loading data analysis, design of advanced turbine controls, development of advanced turbine components, and wind farm performance. Below is a time-lapse video of the installation of the turbine at the Center in August and September of 2009.
As a member of the International Energy Agency (IEA) Wind Energy Executive Committee, the program supports international wind energy research efforts by participating in 10 areas of wind energy research. The program's participation in these international research efforts provides U.S. researchers an opportunity to collaborate with international experts in wind energy, exchange recent technical and market information, and gain valuable feedback for the U.S. industry. For more information on IEA activities, visit the International Energy Agency Web site.