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19.10.2021 | Solar energy: How well informed are you - a quiz

Bright as the sun

As Switzerland's largest producer of renewable energy, the expansion of solar energy is an important part of Axpo's strategy. Thanks to our expertise, we know how to do that abroad, as well as in Switzerland. What do you know about solar energy? See if you can outshine the sun with your knowledge. 


1. What do solar cells use to transform light into energy?

A)    Electromagnets

B)    Semiconductors

C)    Superconductors

B – Semiconductors

Semiconductors are solid components that have an electrical conductivity lying between that of electrical conductors and non-conductors. A solar cell works in a relatively simple way: When sunlight hits the solar cell, electrons in the cell are stimulated and they begin to move. An interaction between the sunlight and the semiconductor in the solar cell (usually silicon) takes place. This releases the electrically charged carriers, also known as electrons. The flow of electricity is released through metal contacts on both sides of the cell. Germanium (Ge), boron (Be), selenium (Se) or tellurium (Te) belong to the family of semiconductors.

2. Solar energy is booming. How high was global growth in the last 10 years on average?

A)    20 per cent

B)    39 per cent

C)    52 per cent

B – It's 39 per cent

With an average annual growth rate of 39 per cent in the last ten years, solar energy is growing faster on a global scale than any other energy technology – and doubling its capacity nearly every two years. More here 

3. Solar energy is not only generated with panels on buildings, but also with...

A) genetically modified climbing plants that transform sunlight into direct current,

B) tiles that look like common roof tiles – in various colours, or

C) tricycles that children play with outdoors when the sun is shining.

B - Roof tiles

You can find out more about the advantages and disadvantages of solar roof tiles here: https://www.energieheld.ch/solaranlagen/photovoltaik-loesungen/solarziegel

And of course, there are also house facades that generate solar energy. More in this article.

4. Axpo and IWB are realising the AlpinSolar project on the Muttsee dam this summer. It will be the largest solar plant in the Alps. How big will it be?

A) 2,000 square metres

B) 6,000 square metres

C) 10,000 square metres

C – 10,000 square metres

In the summer of 2021, Axpo and IWB will build the largest solar plant on the Muttsee dam at an altitude of 2500 m.a.s.l. Denner has contracted all the alpine solar power for a period of 20 years. With the 2.2-megawatt pioneer project, Axpo and IWB are driving forward the expansion of renewable energies in Switzerland and supplying important winter power. The solar plant comprises nearly 5000 bi-facial solar modules. The plant will produce some 3.3 gigawatt-hours of electricity per year – corresponding to the consumption of 740 average four-person households. The solar plant will cover a surface of 10,000 square metres, which corresponds to about 1.5 soccer fields. More on the project here

5. Who was awarded the Nobel Prize for his work on photovoltaics?

A) Albert Einstein

B) Thomas Edison

C) Edmond Becquerel

A – Einstein

Yes. You read right. In 1921, Albert Einstein was awarded the Nobel Prize in physics, but not for his theory of relativity. That's a widespread myth. The prize was awarded for his work in theoretical physics, especially for the discovery of the law of photoelectric effect. The photovoltaic effect was discovered in 1839 by the French physicist Alexandre Edmond Becquerel. Among other discoveries, Edison is known as the inventor of the light bulb.

6. Which sunlight particles help generate electricity with solar cells?

A) Electrons

B) Protons

C) Photons

C – Photons

Light comprises photons that carry electro-magnetic radiation. The photon, also known as a light quantum or light particle, does not have a mass, but it has energy. When a photon comes in contact with semiconductors or metal electrons they are released from the structure and can move freely thanks to this energy (photoelectric effect).

7. Silicon can function as a semiconductor because...

A) Its molecular structure is similar to copper 

B) Conductive crystals are created through sunlight

C) Added impurities allow the free movement of electrons


C – Impurities make it possible

In its normal, crystalline form silicon is not a good conductor because the electrons cannot move freely. However, when tiny quantities of impurities are added, the electrons can move and generate a tiny bit of electricity.

8. What's important for the functioning of a solar plant on a rooftop?

A)   A battery

B)   An inverter

C)   A connection to the power grid

B – An inverter

The inverter is the core of every solar installation: It transforms the direct current from the solar module into the alternating current conforming to the grid so that it can be fed into the in-house power grid.

9. How is energy from the sun created

A) Through gravitation energy from material falling into the sun

B) Through the fusion of hydrogen atoms with hydrogen molecules

C) Through the fusion of hydrogen nuclei with helium nuclei

C is the right answer 

In the core of the sun, hydrogen nuclei fuse to helium nuclei at temperatures of 15 million degrees centigrade. That is how solar energy is created. Temperatures on the sun's surface are only about 5700 degrees centigrade.

10. Bertrand Picard was the first pilot to fly around the world in an aircraft propelled solely by solar energy. When was that?

A) 2018

B) 2017

C 2016 

C – 2016

Aviation pioneer Bertrand Piccard flew around the world with his solar aircraft Solar Impulse2. The journey with his partner André Borschberg that lasted until July 2016 took over a year and covered over 42,000 kilometres. The last of many stops ended in Abu Dhabi, which was the starting point of the journey.

Here's how we rate your result

8-10 correct answers

Brilliant: Your knowledge on the topic of solar energy outshines the sun. Bravo!

4-7 correct answers

Light and shadows: With your knowledge on the topic of solar energy you're in the good average. Want to improve that? Then get up to date on solar energy and  Alpinsolar here.

1-3 correct answers

Cloudy: There's hardly any sun shining through the clouds on the topic of solar energy. You could do better, right? You will find information  on solar energy and  Alpinsolar here.

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