30.06.2020 | Test your energy knowledge (4)

When wind becomes electricity

On- and offshore wind power is experiencing a boom as a renewable energy. The Energy Strategy 2050 envisions a strong expansion of wind energy in Switzerland. However, there is invariably local opposition when concrete projects come to the fore. Axpo is active in wind energy through its subsidiaries CKW and Volkswind. What do you know about electricity from wind power? Here's our test.


1. What is the proportion of wind energy in Switzerland's power production?

A)    Slightly below 10 %

B)    Slightly below 5 %

C)    Less than 1 %

C – Less than 1 %

Average estimated electricity production from wind power in Switzerland amounts to 128 gigawatt-hours. According to statistics by the Swiss Federal Office of Energy, Switzerland's annual production from wind power plants was 122 GWh in 2018. This covers the consumption of 36,500 Swiss households or less than 0.2% of Swiss power production. Find out where Axpo stands on wind power here

2. How many wind power plants does Switzerland currently have?

A)    37

B)    130

C)    321

A – 37

Our country currently has 37 wind plants with an installed capacity of approx. 75 MW. The largest wind farm is located on the Mont Croisin in the Bernese Jura near St. Imier: The farm comprises 16 turbines with a total capacity of 23.6 MW. Other large-scale plants are located in the Rhone Valley (VS), in Entlebuch (LU) and on the Gütsch above Andermatt (UR). Read about our subsidiary CKW's wind power plant in the Entlebuch here.

The CKW wind power plant in Entlebuch is the largest in Central Switzerland

3. Since when has wind power been commercially utilised in Switzerland?

A)    1964

B)    1986

C)    1989

B – 1986

Switzerland's first wind energy plant with an output of 28 kW was commissioned near Soolhof (Langenbruck) in 1986. It was operated by the Ökozentrum Langenbruck. 

4. As a rule, what is the height of onshore wind turbines?

A)    40 to 70 metres

B)    100 to 130 metres

C)    150 to 200 metres

B – 100 to 130 metres

Onshore wind power plants are between 100 and 130 metres high from the ground to the hub – even higher counting the rotor blades. Find out how they work in this video.

Wind power plant: Critics say they are a blot on the landscape

5. The government wants to strongly develop wind power according to Switzerland's Energy Strategy. How much wind power is needed by 2050?

A)    600 GWh

B)    2000 GWh

C)    4000 GWh

C – 4000 GWh

According to the Swiss Federal Office of Energy wind energy has strong development potential in Switzerland: By the year 2020, wind energy plants will produce about 600 GWh of electricity annually. By 2050, production will be at 4000 GWh. Suitable sites are located in the Jura mountains, as well as the Alps and Prealps in the western midlands of Switzerland. However the development target is very ambitious, as explained in this article. The other obstacle is frequent local opposition to wind plant construction. See more details here.

6. What is the optimal wind turbine speed to achieve maximum output?

A)    8-10 m/s

B)    12-15 m/s

C)    20 to 25 m/s

B – 12 to 15 m/s

Wind energy plants make use of the kinetic energy from the air. Modern wind power plants comprise a mast, a nacelle which holds the machine equipment, and a rotor usually with three rotor blades. They begin rotating at wind speeds of 2 metres per second (m/s). A wind power plants starts generating electricity at 4 m/s. The maximum capacity is reached at 12 to 15 m/s. As a rule, the wind turbine is turned off during storms to avoid damage. The ends of the rotor blades can reach speeds of over 200 km/h. Power production depends on the wind speed (power production proportional to the wind speed cubed).  When wind speed is doubled 23, eight times more energy is produced. And: Every wind power plant feeds a giant database. Read about the reasons why here.

7. How long can a wind power plant produce electricity (service life)?

A)    Approx. 10 years

B)    Approx. 20 years

C)    Approx. 30 years

B – Approx. 20 years

A wind power plant can generate electricity for about 20 years before it has to be replaced. Nearly all the components in modern wind power plants, including the towers, are made of steel. The only exception are the rotor blades that are generally made of fibre-reinforced plastics. The service life of steel can be very precisely calculated. In addition, the service life of a plant also depends on average wind force exposure.

8. Which power source creates the least CO2-emissions throughout its entire life cycle?

A)    Nuclear

B)    Wind power

C)    Solar energy

B – Wind power

During its life cycle, wind energy produces the least amount of CO2 (13g CO2-eq/kWh), followed by nuclear power (15g CO2-eq/kWh) and solar energy (80g CO2-eq/kWh). In comparison to fossil fuels such as coal (870g CO2-eq/kWh), solar energy also has a very good CO2 footprint.

The La Penuca wind farm in Spain

9. Which European country uses the most wind power to cover its energy needs?

A)    Germany

B)    Denmark

C)    Portugal

B – Denmark

In 2018, wind power production amounted to 14% of all power consumption in Europe (source: WindEurope). The proportion of wind power in the EU leader Denmark's power mix was 41 % in 2018, followed by Ireland with 28 % and Portugal with 24 % and Germany with 21 %. And by the way: China, the USA, Germany, India, Spain/Portugal and England are the countries that dominate the global wind energy market. As with solar energy, China is the most important market. The highest growth rate is currently taking place in Asia.

10. Wind force is classified on the Beaufort scale. How many levels are there?

A)    8

B)    13

C)    15

B – 13

The Beaufort scale  (Bft) categorises wind forces in 13 levels from 0 (clam) to 12 (hurricane). The Beaufort scale is not an objective scale; it is based on visual observation of wind impacts. The scale is named after Sir Francis Beaufort (1774-1857) is widely used to describe wind force. By the way: Level 6 is a strong breeze, level 7 a high wind, and 8 a gale. You can see what Switzerland's wind situation is here.

8-10 correct answers

Tornado: Wind is more than moving air for you. You’re very familiar with the topic. Good for you.


4-7 correct answers

Windbreaker: Your knowledge is like the wind - unfortunately it isn’t always blowing strongly, sometimes not at all. And that's how erratic your answers were. Want to change that? Get up to date on renewable energies and wind power here.


1-3 correct answers

Tea-light: Any knowledge on the topic of wind dissipated at Beaufort force 13 and blew out the light. Don’t you think you could do better? Find information on renewable energies and wind power here

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