01.03.2021 | Test your energy knowledge (4)

Solar power from the mountains – how does that work?

According to the Energy Strategy 2050, the majority of power consumption in Switzerland will have to be covered by additional renewable sources. The expansion of photovoltaics (PV) will play an important role here. And for Axpo as well. We are realising the pioneer project AlpinSolar in the Canton of Glarus. Have you heard about it already? Or seen the short TV commercial before the evening news (Tagesschau)? What do you know about solar electricity and AlpinSolar? Test your knowledge in our quiz.

1. According to the Federal Energy Strategy 2050, how high must the proportion of solar power in total power consumption be?

A) 30 per cent

B) 40 per cent

C) 60 per cent

B – 40 per cent

According to the Energy Strategy, the Federal Office of Energy forecasts an installed capacity of 37.5 gigawatts for solar power in Switzerland in the year 2050 (scenario zero basis). That would correspond to an increase by a factor of 13 as compared to today. Approximately 34 terawatt-hours of solar power will cover 40 per cent of total annual consumption. A solar power share of 32 per cent is estimated for the winter half-year. 

2. What is the most commonly used material in solar cells?

A)    Chrome

B)    Nickel

C)    Silicon

C – Silicon

A solar cell is about the size of a one's palm and comprises two layers that are two to three tenths of a millimetre thick. Today, most solar cells are manufactured from silicon. Their raw material, quartz sand, is available in sufficient quantities on earth – and silicon is considered to be environmentally compatible. Read how and when solar cells found their way into light here

3. Axpo is building the pioneer AlpinSolar project in the Canton of Glarus. Where exactly?

A)    On the Muttsee dam at 2500 m.a.s.l.

B)    Near the Limmernsee dam at 1857 m.a.s.l.

C)    On the Oberblegisee above Braunwald at 1422 m.a.s.l.

A – On the Muttsee dam at 2500 m.a.s.l.

The pioneer project is located on the Muttsee dam at an altitude of 2500 m.a.s.l. Spanning 1054 metres, it is the longest dam in Switzerland and the highest elevation dam in Europe. 250 000 m3 of concrete were used for the gravity dam and the reservoir can store up to 23 million m3 of water. The dam is part of the Limmern pumped storage plant (LPSP), which functions like a battery in the mountains.

Axpo CEO Christoph Brand comments on the solar pioneer project: "We are proud to realise the largest alpine solar plant together with strong partners, and, in doing so, advance the energy turnaround in Switzerland."

Christoph Brand, CEO

4. Axpo looked for a strong project partner. Who is it?

A)    EKZ

B)    EWZ

C)    IWB 


The energy service providers Axpo and IWB have joined forces to transform the Muttsee dam into the largest alpine solar plant in Switzerland. "The company consistently strives for a climate-friendly energy supply. This includes the expansion of electricity production from solar energy with targeted investments in Switzerland," says Claus Schmidt, CEO of IWB.

5.     Who will purchase the power at a fixed price for 20 years? 

A)    Coop

B)    Denner

C)    Lidl

B – Denner

The third Axpo partner is Denner, the largest discounter in Switzerland. This commitment makes sense for Denner's CEO Mario Irmiger: "This project is a further milestone in our sustainability strategy and reaffirms our commitment to climate goals. Our aim is to continue to exclusively draw our electricity from renewable sources, in order to support the responsible use of natural resources."

6. What do experts call this type of long-term power contract at a fixed price?

A)    Power Purchase Agreement

B)    Fix Power Deal

C)    Long-time Power Agreement

A – Power Purchase Agreement

PPAs are not yet well known in Switzerland, but are developing rapidly around the world. They replace the anonymous procurement of electricity from unknown sources. PPAs are of special importance because they accelerate the transition to a renewable energy supply. They create transparency and help consumers establish a direction connection to "their" power source.

PPAs can be concluded for solar plants as well as hydropower plants. The more power that gets directly to consumers through PPAs, the smaller the proportion of non-renewable power consumption.   

7. How much power will the AlpinSolar facility produce after completion of construction as of the fall of 2021?

A)    2.2 megawatts

B)    2.2 gigawatt-hours

C)    3.3 gigawatt-hours

C – 3.3 gigawatt-hours

When talking about electricity we have to differentiate between capacity measured in kilowatts and production, which is measured in kilowatt-hours. The plant at the Muttsee will produce an average of 3.3 gigawatt-hours of electricity annually with a capacity of 2.2 MW. This power covers the annual average consumption of 740 average four-person households. 

8. 4872 solar panels will be mounted on the Muttsee dam wall. How large is the solar plant?

A)    It covers a surface of 1500 m2

B)    a surface of 20 000 m2

C)    a surface of 10 000 m2

C – 10 000 m2

The surface of the solar plant at the Muttsee corresponds to the size of about one and a half soccer fields. The Muttsee dam is extremely well suited for a photovoltaic plant thanks to its existing infrastructure, its orientation and its altitude: 

  • Owing to the alpine location at 2500 m.a.s.l., solar power is particularly effective and generates lots of power in the winter thanks to snow reflection and a lower incidence of fog.
  • The Muttsee dam faces the south and, as a result, is exposed to sun all day long.
  • The Muttsee dam has an optimal angle – snow slides off the surface on its own.
  • Only existing infrastructure will be used so that no additional open space is needed for construction.
  • Some of the infrastructure (e.g. 16-kV grid connection) is already in place.

9. What's special about an alpine solar plant versus a plant in the lowlands?

A)    It produces more power in summer

B)    It produces more power in winter

C)    It is easier to maintain

B – It produces more power in winter than a plant in the lowlands.

During the winter, Switzerland produces significantly less power than it consumes. This lacking power in winter has to be imported. The situation will intensify in the upcoming years when the Swiss nuclear plants are taken off grid. It is therefore important to find solutions for the production of additional power from renewable sources during the winter. The large-scale, alpine power plant in the Glarus Alps will make a contribution: It will generate 50 per cent of its production during the winter.

Because: Solar plants in the lowlands are often under the fog line during the winter months – there is much less fog and more sun at high altitudes. In addition, PV plants like the cold. The efficiency of solar modules is higher at low temperatures than when it is hot. And sunlight is reflected by the snow cover and results in higher solar power production. This is called the Albedo effect. Furthermore, the angle of the dam wall is optimal for solar power production in winter. More details here .

10. What can you do with a kilowatt-hour of solar power?

A)    Cook 240 eggs

B)    Watch TV for 30 hours

C)    Work on the computer for 10 hours

A – Cook 240 eggs

We admit that this question was a bit tricky. Did you guess right? It's the eggs. One kWh of electricity can power a common television for 15 hours and a computer for 7 hours. You can also do a 5-kilogram load of laundry at 60 degrees centigrade with one kilowatt-hour of electricity, or vacuum for 93 minutes, withdraw money from the ATM 86 times, or ride the subway for 21 minutes.

How we rate your result

8-10 correct answers

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