History of Danish Wind Power - Wind Power for the World: The Rise of Modern Wind Energy - page 42

3.4 The First “Golden Age” of Danish Wind

Power: 1900-1920

During the last decades of the 19th century, three outstanding
personalities have had a deep influence on the development of wind
power in Denmark. One of them, N. J. Poulsen, by a creative inter-
pretation of the new US technologies; the second one, Christian
Sørensen, by innovative use of the European windmill tradition and
the third one, Poul la Cour, by a systematic investigation in the basic
fundamentals of wind power [1].
Around 1900, several new windmill producers with diferent
backgrounds entered the market. A few of them had originated
as millwrights, but as traditional mill building was mostly wood
work, while iron and steel were the primary materials for the new
types of windmills, many of the new producers had a background
as blacksmiths. Iron foundries also played an important role in
the development, both as suppliers of parts for the windmills or in
some cases also as windmill producers.
Three diferent types of the new windmills were produced:
(1) Multi-bladed “power windmills” with pitch-regulated wooden
blades—one of the types originally produced by the Esbjerg
factory.
(2) Windmills with 4, 5 or 6 (in few cases 8) blades, each with
a row of adjustable vanes (also named “shuttered sails”)—as
introduced by Christian Sørensen and further developed by
Poul la Cour.
(3) Small multi-bladed windmills with fixed iron blades, used for
water pumping. They were in principle very similar to the US
Aermotor, introduced by Thomas O. Perry, and later copied
and produced all over the world.
The first two types were produced with diameters up to 18 m
or 20 m, and usually named “wind motors”, while the third type
had a diameter of 3 m to 5 m.
The total number of windmills produced during the first
decades of the 20th century can be estimated from the second
agricultural statistics for the year 1923 [6]. In that year, 16 600
Danish farms had their own windmill. The statistics were made
at a time when the use of wind power was already in decline, and