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Johannes Juul (1887-1969)

Johannes Juul was a Danish engineer who was born in Ormslev near Aaurhus. As a child he attended a free school, finding a passion for physics, before becoming a student at Askov High School at the age of seventeen. Here he was one of the first students to study wind electricity applications under the pioneer, and later colleague, Poul la Cour. After his time in Askov, Juul went on to qualify as an electrician at Copenhagen’s Machinist School in 1914. Following his qualification Juul set up his own workshop in Køge working as an electrical installer. It was here where he developed his first invention, which was an electric oven. He created a model with hot plates, operating at 6, 11 and 14 volts. This allowed Danish housewives to save power and reduce risk. After patenting the design, the oven began production in 1934 and remained popular until the late 1950s.

Juul put his education under la Cour into practice following the Second World War. Denmark had suffered from fuel shortages during the war, and because of this Juul embarked on a wind turbine project beginning in 1947. After experimentation with wind tunnels, Juul developed a 10 kW wind turbine that was installed in 1950 at Vester Egesborg. Two years later in 1952, he produced a turbine on the island of Bogø with a power output rating of 45 kW. Juul’s biggest feat was the Gedser turbine, built in 1957. This turbine had a power rating of 200 kW, and it was designed to improve on the inefficiencies of the Bogø turbine. Gedser was viewed as a success as it managed to operate between 1957 and 1967 without the need for maintenance, demonstrating its remarkable durability. However, in 1962 the Windpower Committee had concluded there was no reason to develop wind power due to its cost despite its success. Juul, at the age of 75, disagreed with the verdict and his conclusions were confirmed when Denmark became the greatest supplier of wind turbines in the world market at the end of the twentieth century. Juul passed away in 1969, however his legacy laid the foundations for the wind turbine industry.


 Danish Wind Industry Association – The Wind Energy Pioneers: The Gedser Wind Turbine

Johannes Juul – Wikipedia

Wind Power – Peter Musgrove, 2010