The wind is a free, clean, and
inexhaustible energy source. It has served humankind well for many
centuries by propelling ships and driving wind turbines to grind
grain and pump water. Denmark was the first country to use wind for
generation of electricity.
The Danes were using a 23-m diameter
wind turbine in 1890 to generate electricity. By 1910, several
hundred units with capacities of 5 to 25 kW were in operation in
Denmark (Johnson, 1985). By about 1925, commercial wind-electric
plants using two and three-bladed propellers appeared on the American
market.
The most common brands were Wincharger
(200 to 1200 W) and Jacobs (1.5 to 3 kW). These were used on farms to
charge storage batteries which were then used to operate radios,
lights, and small appliances with voltage ratings of 12, 32, or 110
volts.
A good selection of 32-VDC appliances
was developed by the industry to meet this demand. In addition to
home wind-electric generation, a number of utilities around the world
have built larger wind turbines to supply power to their customers.
The largest wind turbine built before the late 1970s was a 1250-kW
machine built on Grandpa’s Knob, near Rutland, Vermont, in 1941.
This turbine, called the Smith-Putnam
machine, had a tower that was 34 m high and a rotor 53 m in diameter.
The rotor turned an ac synchronous generator that produced 1250 kW of
electrical power at wind speeds above 13 m/s.
After World War II, we entered the era
of cheap oil imported from the Middle East. Interest in wind energy
died and companies making small turbines folded. The oil embargo of
1973 served as a wakeup call, and oil-importing nations around the
world started looking at wind again. The two most important countries
in wind power development since then have been the U.S. and Denmark
(Brower et al., 1993).
The U.S. immediately started to develop
utility-scale turbines. It was understood that large turbines had the
potential for producing cheaper electricity than smaller turbines, so
that was a reasonable decision. The strategy of getting large
turbines in place was poorly chosen, however. The Department of
Energy decided that only large aerospace companies had the
manufacturing and engineering capability to build utility-scale
turbines.
This meant that small companies with
good ideas would not have the revenue stream necessary for survival.
The problem with the aerospace firms was that they had no desire to
manufacture utility-scale wind turbines.
They gladly took the government’s
money to build test turbines, but when the money ran out, they were
looking for other research projects. The government funded a number
of test turbines, from the 100 kW MOD-0 to the 2500 kW MOD-2. These
ran for brief periods of time, a few years at most. Once it was
obvious that a particular design would never be cost competitive, the
turbine was quickly salvaged.
Denmark, on the other hand, established
a plan whereby a landowner could buy a turbine and sell the
electricity to the local utility at a price where there was at least
some hope of making money. The early turbines were larger than what a
farmer would need for himself, but not what we would consider utility
scale.
This provided a revenue stream for
small companies. They could try new ideas and learn from their
mistakes. Many people jumped into this new market. In 1986, there
were 25 wind turbine manufacturers in Denmark. The Danish market gave
them a base from which they could also sell to other countries.
It was said that Denmark led the world
in exports of two products: wind turbines and butter cookies There
has been consolidation in the Danish industry since 1986, but some of
the companies have grown large. Vestas, for example, has more
installed wind turbine capacity worldwide than any other
manufacturer.
Prices have dropped substantially since
1973, as performance has improved. It is now commonplace for wind
power plants (collections of utility-scale turbines) to be able to
sell electricity for under four cents per kilowatt hour. Total
installed worldwide capacity at the start of 1999 was almost 10,000
MW, according to the trade magazine Wind Power Monthly (1999).
No comments:
Post a Comment