MODERN HISTORY

Turbines from 1980's


The Riisager turbine
Risaager wind turbine        A carpenter, Christian Riisager, however, built a small 22 kW wind turbine in his own back yard using the Gedser Wind Turbine design as a point of departure. He used inexpensive standard components (e.g. an electric motor as generator, and car parts for gear and mechanical brake) wherever possible.
        Riisager's turbine became a success with many private households around Denmark, and his success gave the present day Danish wind turbine manufacturers their inspiration to start designing their own wind turbines from around 1980.






Competing turbine designs
Darrieus biplane wind turbineDarrieus biplane wind turbine        Some designs, including the Riisager design were partly based on solid experience from the classical Gedser wind turbine or classical slow moving multi-bladed American "wind roses", others were more revolutionary including vertical axis Darrieus machines, machines using flaps for power control, or hydraulics for the transmission system, etc. etc. Most machines were very small by today's standards, usually 5 to 11 kW of food.
        In the side there is a picture from the secret testing grounds of Vestas Wind Systems in 1979: the engineer Léon Bjervig next to his 12 kW 7.3 m rotor diameter Darrieus "biplane" machine.








The Tvind 2 MW machine
The Tvind wind turbine (2 MW)        One important exception to the rule of small machines was the Tvind 2 MW machine, a fairly revolutionary machine (in a political sense, too, having been built by idealist volunteers, practising gender quotas and other politically correct activities, including waving Chairman Mao's little red book). The machine is a downwind machine with 54 m rotor diameter running at variable speed with a synchronous generator and indirect grid connection using power electronics. The machine is still running nicely.
        Early Danish wind turbine development was thus a far cry from simultaneous government sponsored research programmes on very large machines in Germany, USA, Sweden, the UK, or Canada.
        In the end, improved versions of the classical, three-bladed upwind design from the Gedser wind turbine appeared as the commercial winner of this wild competition, but admittedly not without a number of wreckages, mechanical, and financial.



Bonus 30 kW
Bonus 30 kW wind turbine        The Bonus 30 kW machine manufactured from 1980 is an example of one of the early models from present day manufacturers. Like most other Danish manufacturers, the company was originally a manufacturer of agricultural machinery. The basic design in these machines was developed much further in subsequent generations of wind turbines.





Nordtank 55 kW
The Ebeltoft wind farm, DK        The 55 kW generation of wind turbines which were developed in 1980 - 1981 became the industrial and technological breakthrough for modern wind turbines.
        The cost per kWh of electricity dropped by about 50% with the appearance of this generation of wind turbines. The wind industry became much more professionalised, and the parallel development of the European Wind Atlas Method by Risoe National Laboratory was extremely important in lowering kWh costs.
        The picture shows a particularly imaginative way of siting these Nordtank 55 kW wind turbines, on a harbour pier at the town of Ebeltoft, Denmark. Red tipped rotor blades have disappeared completely from the market since then, after it was discovered that birds do not fly into the rotors anyway.






The great California wind rush
The Ebeltoft wind farm, DK        Literally thousands of these machines were delivered to the wind programme in California in the early eighties. The Micon 55 kW is one example of such a machine, delivered to one huge park of more than 1000 machines in Palm Springs, California.
        Having started series manufacturing of wind turbines about 5 years earlier, Danish manufacturers had much more of a track record than companies from other countries. About half of the wind turbines placed in California are of Danish origin.
        The market for wind energy in the United States disappeared overnight with the disappearance of the Californian support schemes around 1985. Since then, only a tiny trickle of new installations have been commissioned, although the market seems to have been picking up, lately. Germany is now the world's main market and the country with the largest wind power installation.