An Overview of Some Historic Wind Turbines: Part 2
In the 1970s oil crisis, many countries began to explore alternative energy options and their viability. In the US, NASA, and the Department of Energy have collaborated to develop a series of megawatt large research wind turbines known as Mod series.
The Mod Series
The wind turbines developed in the mod series were very expensive and meant to be a technology drivers.
Mod 0A
Mod 0 and its improved variant Mod 0A were developed by a contractor Westinghouse. The Mod 0A used a two-blade rotor 38 m in diameter and had a downwind configuration to drive a 200 kW generator. The Wind turbine was installed in 1977 in Clayton, New Mexico in a small municipality.
The Turbine had a lattice tower and flaps on the partial span of the rotor for speed control. It was in operation for 4 years until it was removed in 1981.
Mod 1
After Mod 0A, a much bigger version of the downwind configuration wind turbine was developed by a new contractor General Electric. The Mod 1 turbine was 2.5 times the size of Mod 0A and had a rated capacity of 2MW.
The 61 m diameter Turbine was installed near Boone, North Carolina in 1978. This turbine proved to be disastrous as its low-frequency noise disturbed its neighbors and soon people lodged plenty of complaints about the noise.
The turbulent wind passes through the blade passage before the lattice towers induces low-frequency noise. Due to noise issues, the turbine was removed before even supplying elecricity to the grid.
Mod 2
The Mod 2s turbines were developed by Boeing company. They used upwind rotor configration and were 2 times larger than the Mod 1 turbines and had a rated capacity of 2.5 MW. Instead of fiberglass they chose steel for rotor blades construction.
Three Mod 2 turbines were installed near Golendale , Washinghton and one each in Solana, California and in Medicine Bow, Wyoming.
Mod 5B
The size of Mod 5B wind turbine was further increased and grew to 98 m in diameter with a rated capacity of 3.2 MW . The turbine had a tubuar steel tower and was installed in Oahu , Hawaii.
The Mod 5B wind turbine was quite succesful and performed better compared to earlier Mod series turbines. However, still, it was not cost competitive relative to the other commercial operating wind turbines of the time.
Growian Wind Turbine
Growian wind turbine was developed with the support of german ministry of technology and development. Although, initially intended to design for 1 MW capacity later contracter increased the size and capacity.
The 100 m in diameter wind turbine with 3 MW rated capacity had two bladed rotor with a downwind configuartion. The turbine was installed in 1983 and operated only for 450 hours and taken out of service in 1987. The turbine costs 2 times the estimated cost.
Nibe A & B Turbines
The two wind turbines were installed at Nibe , jutland, Denmark between 1979-80. The turbines had rated capcity of 630 kW and 40 m in dia. The objective was to evaluate two different configurations. Nibe A had a tradaitional upwind rotor blades braced with sruts and stays while Nibe B had cantilevered blades which proves to be successful and later new wind turbines were developed on this design.
Tjaereborg Test Site
The Tjaereborg test site hosted several research wind turbines including the oldest turbine supported with the concrete tower that was installed in 1988 and after operating for a decade, became the longest working hours research wind turbine in the world.
Tvind School Turbine
Tvind school was a Danish traditional training institute located near the Ulfaborg, windy coast of jutland. The Turbine developed by this institute, represnts a historic significance in the development of Danish moden wind turbines.
When the government was considering nuclear power, Twind students and teacher had developed a wind turbine with its limited budget and given a clear message to government that we want wind energy. The wind Turbine development started in 1975 and completed in 1978. At the time it was largest wind turbine in the world.
For power control through blades pitch ,They used 27m long cantilevered blades and attached the fiber glass blades to hub through flanges, a method developed by ultcher Hutter.
It was this adoption, that gave Tvind wind turbine a land mark success and later revolunize the wind energy industry.
For overspeed protection,if pitch system failed, they deployed parachute over the rotor blade end and it worked.
After more than three decades , the turbine is still opeating and this is remarkable achievement of tvind turbine that lasted for so long.
Resource
For indepth read of each turbine listed above, please go through this resource.
Gipe P, Möllerström E. An overview of the history of wind turbine development: Part II–The 1970s onward