Benefits of NASA’s "Good Stewardship" Regarding the Agency’s Participation in the Federal Wind Energy Program

NASA Lewis’s involvement in the Federal Wind Energy Program from 1974 through 1988 brought a high degree of engineering expe­rience and expertise to the project that had a lasting impact on the development of use of wind energy both in the United States and inter­nationally. During this program, NASA developed the world’s first mul­timegawatt horizontal-axis wind turbines, the dominant wind turbine design in use throughout the world today.

NASA Lewis was able to make a quick start and contribution to the program because of the Research Center’s longstanding experi­ence and expertise in aerodynamics, power systems, materials, and structures. The first task that NASA Lewis accomplished was to bring forward and document past efforts in wind turbine development, includ­ing work undertaken by Palmer Putnam (Smith-Putnam wind tur­bine), Ulrich Hutter (Hutter-Allgaier wind turbine), and the Danish

Gedser mill. This information and database served both to get NASA Lewis involved in the Wind Energy Program and to form an initial data and experience foundation to build upon. Throughout the program, NASA Lewis continued to develop new concepts and testing and modeling techniques that gained wide use within the wind energy field. It documented the research and development efforts and made this information available for industry and others working on wind turbine development.

Подпись: 13Lasting accomplishments from NASA’s program involvement included development of the soft shell tubular tower, variable speed asynchronous generators, structural dynamics, engineering model­ing, design methods, and composite materials technology. NASA Lewis’s experience with aircraft propellers and helicopter rotors had quickly enabled the Research Center to develop and experiment with different blade designs, control systems, and materials. A significant blade development program advanced the use of steel, aluminum, wood epoxy composites, and later fiberglass composite blades that generally became the standard blade material. Finally, as presented in detail above, NASA was involved in the development, building, and testing of 13 large horizontal-axis wind turbines, with both the Mod-2 and Mod-5B turbines demonstrating the feasibility of operat­ing large wind turbines in a power network environment. With the end of the energy crisis of the 1970s and the resulting end of most U. S. Government funding, the electric power market was unable to support the investment in the new large wind turbine technology. Development interest moved toward the construction and operation of smaller wind turbine generators for niche markets that could be supported where energy costs remained high.

NASA Lewis’s involvement in the wind energy program started winding down in the early 1980s, and, by 1988, the program was basically turned over to the Department of Energy. With the decline in energy prices, U. S. turbine builders generally left the business, leaving Denmark and other European nations to develop the commercial wind turbine market.

While NASA Lewis had developed a 4-megawatt wind turbine in 1982, Denmark had developed systems with power levels only 10 per­cent of that at that time. However, with steady public policy and prod­uct development, Denmark had captured much of the $15 billion world market by 2004.

TABLE 1

COMPARATIVE WIND TURBINE TECHNOLOGICAL DEVELOPMENT, 1981 -2007

TURBINE TYPE

Nibe A

NASA WTS-4

Vestas

YEAR

1981

1982

2007

COUNTRY OF ORIGIN

Denmark

United States

Denmark

POWER (IN KW)

630

4,000

1,800

TIP HEIGHT (FEET)

230

425

355

POWER REGULATION

Partial pitch

Full pitch

Full pitch

BLADE NUMBER

3

2

3

BLADE MATERIAL

Steel/fiberglass

Fiberglass

Fiberglass

TOWER STRUCTURE

Concrete

Steel tubular

Steel tubular

Source: Larry A. Viterna, NASA.

Most of the technology developed by NASA, however, continued to represent a significant contribution to wind power generation applica­ble both to large and small wind turbine systems. In recent years, inter­est has been renewed in building larger-size wind turbines, and General Electric, which was involved in the DOE-NASA wind energy program, has now become the largest U. S. manufacture of wind power generators and, in 2007, was among world’s top three manufacturers of wind tur­bine systems. The Danish company Vestas remained the largest company in the wind turbine field. GE products currently include 1.5-, 2.5-, and, for offshore use, 3.6-megawatt systems. New companies, such as Clipper Wind Power, with its manufacturing plant in Cedar Rapids, IA, and Nordic Windpower also have entered the large turbine fabrication business in the United States. Clipper, which is a U. S.-U. K. company, installed its first system at Medicine Bow, WY, which was the location of a DOE-NASA Mod-2 unit. In the first quarter of 2007, the company installed eight com­mercial 2.5-megawatt Clipper Liberty machines. Nordic Windpower, which represents a merger of Swedish, U. S., and U. K. teams, markets its 1-megawatt unit that encompasses a two-bladed teetered rotor that evolved from the WTS-4 wind turbine under the NASA Lewis program.

In summary, NASA developed and made available to industry sig­nificant technology and turbine hardware designs through its "good stewardship” of wind energy development from 1974 through 1988. NASA thus played a leading role in the international development and utilization of wind power to help address the Nation’s energy needs today. In doing so, NASA Lewis fulfilled its primary wind program goal
of developing and transferring to industry the technology for safe, reliable, and environmentally acceptable large wind turbine systems capable of generating significant amounts electricity at cost competitive prices. In 2008, the United States achieved the No. 1 world ranking for total installed capacity of wind turbine systems for the generation of electricity.