Introduction - Wind Energy: Renewable Energy and the Environment - page 8

Turbine
Alternator
FIGURE 1.9 Diagram of Enield - Andreau wind turbine, 100 kW.
a 32 m tower. This unit fed electricity into the national grid from 1958 to 1963. Two other units were
located at St. Remy-Des-Landes. The smaller Neyrpic machine had a rotor diameter of 21 m on a
17 m tower, and the asynchronous generator produced 130 kW at 12 m/s. The larger unit had a rated
power of 1,000 kW at 17 m/s and operated for 7 months, until operation ceased in June 1964 due
to a broken turbine shaft. Even though the prototypes clearly showed the feasibility of connecting
wind turbines to the electric grid, the French decided in 1964 to discontinue further wind energy
research and development.
During the 1950s, Hütter of Germany designed and tested wind turbines that were the most
technologically advanced for that time and for the next two decades. The rotors had lightweight
fiberglass blades ( Figure 1.10 ) mounted on a teetered hub with pitch control and coning since the
rotors were downwind. A 10 kW unit was developed and tested, which culminated in a larger unit,
34 m diameter, that produced 100 kW at 8 m/s [17]. This unit had around 4,000 h of operation from
1957 to 1968; however, the experiments proceeded slowly due to lack of funds and problems with
blade vibration.
In Denmark, several hundred systems based on the design by La Cour [18] were built, with
rated power from 5 to 35 kW. The units had rotor diameters around 20 m, four blades, which had
a mechanical connection to a generator on the ground. By 1900, there were around 30,000 wind
turbines for farms and homes, and in 1918, some 120 local utilities in Denmark had a wind turbine,
typically 20-35 kW for a total of 3 MW. At that time, these turbines produced around 3% of the
Danish electricity. Danish interest waned in subsequent years, until a crisis of production of elec-
tricity during World War II. Since the Danes did not have any fossil fuel resources, they looked at
connecting wind turbines into their national grid, and the Danish government started a program to