A wind turbine story | WIND my ROOF

By the end of 2022, 21 of the 56 French nuclear reactors were shut down. In 2021, nearly 70% of the electricity was produced by this energy. Thus, in a context of energy crisis but also of transition, the diversification of the means of production via renewable energies is to be developed.

Throughout history, several machines using wind energy have been created. Used to grind grain, some of them can produce electricity. Contemporary wind turbines are the result of multiple evolutions, what are the inventions that have influenced their development?

The use of mechanical energy: from the 7th to the 21st century

Wind turbines’ history begins with the use of the wind’s kinetic energy to perform mechanical work. At this time, this energy was used to move objects, to refresh places, or to feed. The ancestors of modern wind turbines are the windmills, whose first traces date back to the 7th century. They would flourish in Europe starting in the 11th century.

Persian windmills

In Iran in the 7th century, Persian windmills were the first of their kind and the last ones still exist at the top of the village of Nashtifan. Made of clay and straw, they are composed of wooden blades connected to a vertical axis under which is fixed a rolling stone. The force of the wind on the blades allows the stone to turn and grind the grain.

Traditional European windmills

Windmills became more popular from the 11th century onwards with a more complex version than the Persian model. The windmill is equipped with a tower, the axis tilts and becomes horizontal, the wooden blades are transformed into cloth wings with a wooden frame. A gear system allows them to amplify their movement. It was completed with a brake system to prevent the mechanism from running out of control.

If the shape and size of the mills vary according to the period and the location, the typical mill from the 11th to the 18th century has four rectangular wings. These are oriented according to the direction of the wind thanks to a system of cap placed at the top of the tower or via a base oriented by a rudder.

L'éolienne de Bollée

Bollée’s wind turbine has two iron wheels attached to the top of its column. The first wheel turns when the wind hits it at an angle, and this movement activates a gear that directs the head of the turbine into the wind. The second wheel, placed at the back of the turbine, has blades in the opposite direction of the first one that direct the air flow perpendicularly to drive pumps.

The windmill officially became a wind turbine in 1868 in France, when the Bollée family filed a patent for their windmill under the name “éolienne”, which means wind turbine in English. If the characteristics of this first windmill are similar to those of other windmills, the yields allowed are optimized: the tower gains in altitude (15 m) and the orientation with respect to the wind direction becomes automatic.

Windmills were established in Europe for eight centuries. From the 19th century onwards, a new Eldorado opened up for wind energy, thanks to the advent of electricity and the discovery of the conversion of mechanical energy into electrical energy. The latter is made by a dynamoelectric machine at first, then by an alternator, more powerful.

The conversion of mechanical energy into electrical energy: the precursors of modern wind turbines (late 19th and early 20th century)

Windmills 2.0. convert mechanical energy into electrical energy. The wind sets in motion the rotor blades which are connected to a transmission shaft, drive bearings (with a speed multiplier) and a generator. At the same time, several electric wind turbine projects were launched in Scotland, France, the United States and Denmark.

James Blyth's windturbine

The very first wind turbine to produce electricity was vertical. It was invented in 1887 by James Blyth of Scotland and was 8 meters high. Blyth was the first to place the dynamo on the tower of the wind turbine and not on the ground, which would become the standard on modern wind turbines.

Blyth summarized the problem that would shape a century of research and development: “any fool can make a wind turbine go round to generate electricity, but the challenge is to make one that can be left unattended without over-speeding to destruction [1]”.

Charles de Goyon's windturbine

At the same time in France, Charles de Goyon developed an electric and automated wind turbine from an American multiblade windmill to which he added two dynamos located on the ground in a shed. Measuring 18m high and 12m in diameter, it has a power of 12 kW. It will be the first electric wind turbine marketed in France: installed near Le Havre, it allowed to supply the lighthouse of La Hève.

Charles Brush's wind turbine

Among the first electric wind turbines, the one built by the American Charles Brush in 1888 remains the most famous. Made of cedar wood, it is 18 m high. Its rotor is composed of 144 blades with a diameter of 17 m. To convert the energy supplied by the wind into electrical energy, Charles Brush invented a direct current dynamo.

The wind turbine has a power of 12 kW and has allowed, for 20 years, to feed the batteries of the accumulators of the inventor’s house.

Poul La Cour's wind turbine

Two years later, in 1890, Poul La Cour, a Dane, designed a wind turbine capable of producing electricity. He tested and optimized it in a wind tunnel he had created. With a reduced number of blades (only four), it turns faster and has a power of 25 kW, twice as much as Brush’s. La Cour’s wind turbines were the most widely used until the 1920s.

From 1920, the advances made during the First World War in aeronautics benefited the development of wind turbines and the optimization of blades. The Frenchman Louis Constantin, for example, used aircraft propellers, and the German Kurt Bilau also perfected the aerodynamics of the blades.

Among the notable advances of the interwar period, we can also note the very first connection to an alternating current network (Denmark, 1919), the creation of a wind energy association in France by Louis Constantin, and the design of the vertical axis wind turbine by Darrieus.

The rise of electric wind turbines following the Second World War

Although the development of wind energy was part of Nazi Germany’s plan for self-sufficiency, little progress was made during this period in Europe, except in Denmark, which continued to install electric wind turbines. After the Second World War, research programs were launched in Europe to diversify energy sources and reduce dependence on fossil fuels. The real technical achievements came from the Danish Johannes Juul and the German Ulrich Hütter.

Post-war national programs

In France, EDF created a Wind Energy Division in 1946 within the Studies and Research Department. Thanks to this unit, anemometers were placed all over the country, which allowed the first maps of interest for wind energy to be drawn up.

Three wind turbine tests were carried out by EDF between 1958 and 1962:

The Neyrpic wind turbine (three-bladed 132 kW, 21 m diameter) is installed in 1958 in Saint Rémy des Landes. It operated from 1959 to 1966 and produced 700,000 kWh over this period.
On the same site, a 1000 kW wind turbine (three-blade, 35 m diameter) was tested in 1964. Due to too many technical problems, the wind turbine is dismantled in 1966, with 500 000 kWh produced in two years.
The Best-Romani wind turbine (800 kW, 30 m diameter) named after Lucien Romani was tested in parallel at Nogent-le-Roi between 1956 and 1962.

In Great Britain, the British Electrical Authority was created after the war and financed wind power tests. 3 wind turbines with a power of 100kW each were installed.

The John Brown Engineering wind turbine (three-bladed, 15 m diameter) was installed in 1955 in Orkney Islands.
The De Havilland wind turbine (two-bladed, 24 m diameter) was installed in 1951 in Wales. Due to local opposition to the project and inconclusive tests, the project was abandoned.
On the Isle of Man, a wind turbine (three-bladed, 15 m diameter) was installed in 1959 and produced 230 to 240 MWh/year. The experimentation was stopped for economic reasons after 5 years.

L'éolienne de Johannes Juul

In Denmark, Johannes Juul was responsible for the most advanced wind turbine of its time. He worked for the Copenhagen electricity company (SEAS) on new wind turbines from 1947 and tested several models in the 1950s.

Following in the footsteps of his teacher Poul La Cour, he designed the Gedser wind turbine (24 m diameter) in 1957, which is the closest thing to a modern wind turbine. Composed of a mast and a rotor with three blades oriented towards the wind, it is connected to a generator with a power of 200 kW. A safety system was added with aerodynamic brakes and swivel ends capable of slowing down the rotor in case of too strong winds. The wind turbine operated from 1959 to 1967 and produced an average of 275 MWh / year.

Following in the footsteps of his teacher Poul La Cour, he designed the Gedser wind turbine (24 m diameter) in 1957, which is the closest thing to a modern wind turbine.

Composed of a mast and a rotor with three blades oriented towards the wind, it is connected to a generator with a power of 200 kW. A safety system was added with aerodynamic brakes and swivel ends capable of slowing down the rotor in case of too strong winds. The wind turbine operated from 1959 to 1967 and produced an average of 275 MWh / year.

Ulrich Hütter's wind turbine

In Germany, the best known initiative is that of Ulrich Hütter who works for the Allgaier company. In 1949, he tested a wind turbine with a diameter of 11 m and a power of 10 kW in Holzhausen. In 1957, he developed the two-blade StGW-34 turbine with a power of 100 kW (34 m diameter). The technical innovation lies in the choice of material for the blades, made of fiberglass. His legacy is the “Hütter flange”, a method of attaching the blades to the rotor hub with fiberglass filaments.

The oil shocks and the new wind energy boom until today

The wind energy industry was reborn thanks to the oil shocks, which, as after the war, raised the question of energy independence in the face of oil shortages. While nuclear power was on the rise, the United States, Germany, the United Kingdom, Sweden and especially Denmark began to develop wind power.

The 1970's-80's: The rise of the wind industry in Denmark

In Denmark, the wind energy sector comes from the civil society. It is built thanks to the development of the industry and to the measures taken by the government in place.

In the Danish public opinion, there is a lot of opposition to nuclear power. Wind energy is perceived as an interesting alternative. The civil society invests then in the construction and the promotion of wind turbines.

L'éolienne Tvindkraft

Between 1975 and 1978, a group of students and academics from the Twind School developed the Tvindkraft wind turbine. Still in operation today, the three-bladed wind turbine has a power of 1MW and a diameter of 54m. It captures the back winds. The model of the blades will be used by many other wind turbine manufacturers.

L'éolienne Riisager

In 1976, a carpenter, Christian Riisager, built one of the most advanced wind turbines of its time. It is a three-bladed wind turbine with a diameter of 10 m, a power of 22 kW and wooden blades. This model became popular in Denmark (of the 24 wind turbines operating in Denmark in 1979, 18 were Riisager turbines) and was exported to the USA. 200 such turbines were in operation by 1985.

The Danes, pioneers of wind energy

More generally, agricultural cooperatives install many wind turbines and play an active role in their promotion. They grouped together in an association in 1978 which allowed them to negotiate directly with the manufacturers. The result is a strong attachment of the society to the sector.

The Danish government of the time financially supports the development of wind energy. In 1979, it granted a 30% subsidy for the purchase of wind turbines. In 1981, the first Danish National Energy Plan set the objective of installing 60,000 small wind turbines on the territory by 2000, to produce 8.5% of the energy consumed in the country. In 1985, the government officially abandoned any desire to develop nuclear power. The Chernobyl disaster in 1986 accelerated the development of wind energy, with the Energy Plan 2000 setting a target of 1,500 MW to be installed by 2005.

The development of the world market

Given this favorable climate, the industrial sector is also getting organized. Vestas, today’s market leader, launched its wind turbine business in 1979. In 1981, it synthesized the best innovations in wind turbines and launched the Vestas V15 wind turbine (15 m in diameter, 55 kW power, headwinds), which has become an established feature in the landscape.

In other countries, national programs aim at developing very powerful wind turbines, which turn out to be technical and commercial failures. Thus in the United States, NASA accompanied by General Electric and Boeing conducted several tests between 1977 and 1987 (wind Mod-0 of 2 500 kW to Mod-5 of 3 200 kW). The German government also set up a national program for the development of wind energy (Grosse Wind Energie Anlage Programme) with Hütter, with an objective of 3 000 kW of power. These attempts were not successful and the turbines were dismantled after a few years of use.

At first, it was Danish wind turbines that became popular internationally, especially in California during the “Wind Rush” of the 1980s. During this period, the federal government set a goal of 20% renewable electricity in the country by 2000. The State of California offered a 25% subsidy on wind energy and mapped out areas suitable for wind turbines. At that time, more than 11,000 wind turbines were installed in California.

The technologies diverge according to the manufacturers, the Danish prefering three-bladed wind turbines capturing the front winds, the Germans two-bladed wind turbines capturing the back winds, and the Americans two-bladed or three-bladed wind turbines capturing the back winds.

The rise of modern wind turbines

Since the 1980s, the search for power has led to an increase in the size of wind turbines, the establishment of massive farms and the development of offshore wind power.

In 40 years, the power of an onshore wind turbine has increased 50 times! The V162 developed by Vestas is the most powerful wind turbine: with a diameter of 162 m, its capacity is 6,200 kW. Other wind turbine manufacturers are not to be outdone: Nordex, General Electric, Siemens Gamesa and Enercon have developed wind turbines with similar power ratings.

In parallel with onshore wind turbines, offshore wind energy was developed in the 20th century. In the sea, the winds are stronger and more regular; they have the advantage of having fewer obstacles in their path. Wind turbines can also be larger and generate more power.

In 1991, Denmark, always at the forefront of wind energy, installed a 5 MW wind farm off its coast, in Vindeby. In 2002, the country installed a new 160 MW wind farm in Horns Rev. Since the 2010s, the deployment of offshore wind turbines is accelerating with projects of increasingly powerful wind turbines.

Conclusion

In 2023 for France, the connection target for wind power is between 21.8 and 26 GW. At the end of 2021, the connected capacity was 18.9 GW.

Today, production is mainly driven by onshore and offshore wind. To help achieve these objectives, the means of production using wind are diversifying. Thus, new technologies allow us to get closer to the cities while others are installed there.

On the edge of town: wind turbines have a larger rotor and start to turn for slower winds than those in the countryside;
In the city: they are rather wind turbines that are placed on the roofs, like the WindBox. They benefit from the acceleration of the winds when they go up on the facades of the buildings.

All of these advances put us on the right track to achieving these objectives.

Contact us

We will be happy to exchange with you!

Click here!

Sources

[1] Gipe P, Möllerström E. An overview of the history of wind turbine development: Part I—The early wind turbines until the 1960s. Wind Engineering. 2022;46(6):1973-2004. doi:10.1177/0309524X221117825 “any fool can make a wind turbine go round to generate electricity, but the challenge is to make one that can be left unattended without over-speeding to destruction.”