Environmental Engineering Reference
In-Depth Information
intended to develop an American wind industry more and more
became a blessing for the Europeans. In 1984, Americans still made
up large parts of the market and had thousands of units sold. But
more foreign manufacturers entered the market. European
wind turbines became quickly established in California due to
their diferent but more reliable technical approach, a fact that
particularly applied to the Danish. Two terms were popular at that
time: “American Design” for all US manufactures (see previous
paragraph) and “Danish Design” referring to economical and
reliable Danish wind turbines.
The Danish influence in wind farm development led to a
dominance of 3-bladed wind machines. But still many diferent
concepts with two, three or four blades operating up- or downwind
appeared. Anything having blades, a generator and a tower was
“considered” a wind turbine. Various “mixes” of blades, towers,
nacelle designs, rotation directions, colours and other aspects
of visual appearance were typical for California's wind rush and
created a colourful and diverse mass of spinning rotors dotting the
landscape.
The 1970s US research also gave birth to unknown designs
such as the vertical-axis wind turbine (VAWT) that took a great
upward trend in the California wind rush. There were two major
companies, FloWind
5
6
who developed the vertical
Darrieus turbine further on the basis of intensive 1970s research.
The two firms ofered machines ranging from 100 kW to 250
kW. With their egg beater and onion-like appearance, FloWind
turbines gave the Altamont and Tehachapi Pass a new look while
VawtPowers caught the attention of people in the San Gorgonio
area. Unlike conventional wind turbines, the roughly 500 VAWTs
deployed in the three resource areas had two aluminium blades
instead of fibreglass blades. Manufacturing such blades was
based on a special extrusion process, first applied by Sandia
Laboratories in the mid-1970s. VAWTs were only built from 1983
until 1985. Technical inferiority to horizontal-axis turbines finally
made them disappear from the market. The biggest problem
with VAWTs was that they had to be started with a motor before
and Vawtpower,
5
FloWind was founded in 1982. After the rush years, FloWind faced financial
problems and remained a small light in the industry. In the early 1990s FloWind
developed an advanced three-bladed 300 kW VAWT but disappeared in 1996.
6
VawtPower sold 40 units for a wind farm at San Gorgonio.
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