The spring weather of the last days and weeks treated us with a lot of sunshine and temperatures far above 20 °C. Spring 2020 is sunnier than rarely a spring before. The sun not only supplies us with vitamin D – but can also be used to generate energy.
Solar energy is the energy from which the sun's rays can be generated. This includes not only the energy generated by converting solar radiation into electricity, but also direct solar heat and the thermal use of solar radiation.
The sun's radiant power is based on the electromagnetic radiation that is released on the surface of the celestial body – with an estimated temperature of around 5500 °C, which is almost unimaginable.
How does the use of solar energy work physically?
The sun's rays that reach us are products of the nuclear fusion processes that take place inside the sun. When the rays hit the earth's atmosphere, they still have an intensity of about 1367 watts per m². Some of the solar radiation is already trapped, scattered or reflected in the atmosphere by suspended matter. And the atmosphere itself is already being heated by the sun's rays and thus absorbs a considerable proportion of the radiation.
Whatever remains reaches the earth's surface and unfolds its effect there. The incident sunrays are used by plants for photosynthesis, the conversion of carbon monoxide into oxygen. We owe the air we breathe to this process.
When people use solar energy, they do so in various ways with the help of photovoltaics or phototermics:
- Using solar cells in photovoltaics to generate direct current.
- Heat gain through solar collectors within the scope of photothermal energy
- Electricity generation in solar thermal power plant via heat and steam
- Power generation through sun-heated air in so-called updraft power plants
- Solar ovens or cookers for the heating of food, medical equipment and much more
- Solar balloons whose flight capability is based on the hot air inside
What are the advantages and disadvantages of solar power?
When it comes to the use of solar energy, experts distinguish between solar collectors and photovoltaic systems. With the help of solar collectors, for example, water can be heated for household needs; a storage medium is not provided for here. However, the collectors only perform at their best when the weather is very good and the sky is clear. At night, as soon as the heated water supply is used up, war showers are no longer possible.
With photovoltaic systems, on the other hand, electricity can be generated and fed into the grid. The electricity generated in this way is reimbursed to the producer. Conversely, households with a photovoltaic system can feed electricity into the grid during the day, and at night they can draw electricity from the grid in reverse.
Such systems are of course much more expensive to install than the relatively simple collectors. In addition, users must calculate how large or powerful the system is in order to be able to amortise it sensibly. If you have enough roof surface, a photovoltaic system over 20-30 m² can be depreciated within about 15 years.
It is also costly to store the generated solar energy yourself. Work is still in progress on appropriate chemical storage media – the use of hydrogen cells is conceivable.
How big is the benefit of solar energy?
Larger photovoltaic systems are complex panels of semiconductors that convert solar radiation into direct current. This is converted and can be fed into the power grid. The systems have become much more affordable than 10 or 15 years ago and are one of the most important sustainable methods of generating electricity. Since modern solar cells have an extremely high conversion rate, they also work well in northern latitudes.
But the possibilities are far from exhausting their potential. At least a quarter of the energy requirement could be covered by solar power by the middle of the century. And solar energy can be used not only for the electricity required, but also for hot water and room heating – both actively and passively, preferably in combination with appropriate renovation and insulation of buildings.
Passive and active use of solar energy
Solar energy has been used passively for thousands of years – especially in the orientation of buildings. The aim is to capture the maximum amount of light and heat through the windows. At the same time, so-called "passive houses" must of course also be able to have appropriate thermal insulation so that the "caught" solar heat remains inside.
If, on the other hand, the solar radiation is to be actively used, a solar collector for hot water production or a photovoltaic system is required to generate electricity. Regardless of what users choose, the panels or other components can be incorporated into the design of a building.
Using solar energy – it works almost everywhere
With highly efficient new solar panels, the power of the sun can be converted into energy even in northern latitudes. Even the slightest light irradiation is utilised. And mobile solutions have also been considered. There are solar pads, for example, which are an ideal way of supplying energy for outdoor enthusiasts. The pads are actually portable solar cells. They can be attached to the backpack or the roof of the car and at the end of the day have generated electricity for the mobile phone, the camera or for hot shower water. So solar energy is not only incredibly sustainable – it is also extremely portable!
NIKIN – for a more sustainable approach to the environment
Although we at NIKIN are primarily concerned with sustainable materials in the fashion industry and fight against global deforestation, it is also important for us to think sustainably in other areas of life. We want to motivate people to rethink their lifestyle and possibly make it more sustainable. It is time to think about alternative sources of energy to the conventional ones. One of these is the use of solar energy, which is gradually becoming more affordable thanks to technical progress and is also experiencing an upswing in Switzerland.