You all know the feeling: An hour of sport at school, then learning for a maths test, it's been three hours since you had your breakfast - you feel really tired. But after a little snack at break-time, you start to come back to life. What has happened? You have provided your body with energy. Just like plugging a hairdryer into an electrical socket: Electricity flows and it starts to blow at full power.
Energy- an invisible master of metamorphosis
Energy is invisible, we all contain it, as does everything that surrounds us. It is never lost, but is converted from one form of energy into another. An example: You will almost certainly have seen a large wind turbine. When the wind blows, the rotor blades turn. The resulting rotational energy is then converted into electrical energy - and into electricity therefore - via a turbine and a generator.
Energy sources that never run out
Wind can also be used to produce electricity. This is practical because the wind always blows - sometimes a lot, sometimes less - but this source of energy never dries up, it is … infinite.
The same is true of water, whose fluid energy (also called kinetic energy) is converted into electricity by turbines in a hydroelectric power station. Naturally it makes most sense to locate such hydroelectric power stations in places where the water flows with great power - for example at dams on reservoirs.
Sunny times
The power of the sun - our biggest source of heat and energy - can also be used in many ways: Ever noticed the flat, black containers with tubes on the roof of a house? These are collectors through which water flows, and which is in turn warmed by the sun. And the warm water can then be used for showers and heating.
And electricity can also be produced with the sun. Either with rows of solar cells on the roof, placed together on the roof to create a blue glistening module, or in a solar power station that not simply supplies one house with electricity but thousands.
Bonfires - a romantic source of energy
If you have an open fire at home or have had a bonfire in the garden, then you are familiar with another infinite source of energy: biomass, which includes wood as well as plants - so-called organic substances which grow again with the aid of sunlight.
Where does our electricity come from?
In addition to the infinite, renewable energy sources, there are (as well as nuclear energy) the so-called fossil energy sources; these include coal, crude oil and natural gas. They are called fossil fuels because they were formed about 250 million years ago from plants. And as these do not grow again they are also called "finite energy sources".
The bulk of our energy needs - electricity, heat, as well as energy for road transport and industrial production therefore - currently comes from fossil energy sources. As these reserves are only available in limited amounts and their combustion creates environmentally-damaging CO2 (carbon dioxide), people have been trying for many years now to find more environmentally-friendly energy sources and energy technologies to meet our energy requirements. But let's not forget: Saving energy can also make an enormous contribution to reducing the burden on our fossil energy resources …
Looking at energy problems from a global stance
Two other aspects play a role when we consider our energy future: On the one hand the world's population is rising every day, which means that more and more people need more and more energy and that the reserves are being used up increasingly quickly.
On the other hand, we in Germany are an import nation when it comes to energy, i.e. we have to buy natural gas and crude oil from other countries as we do not have these natural resources. Some regions that have crude oil, however, are political crisis areas in which wars are being waged. If, for example, roads and industrial facilities are destroyed in such a country, a functioning oil trade is no longer possible and we have to meet our need for crude oil from other sources.
When the sun is supposed to turn the light on at night ...
Great, you're probably thinking, these never-ending energy sources are all to be had for free right on our very doorstep, what are we waiting for?
There is a small problem, though: Solar energy can only be produced during the day, and mainly in the summer months - when the sun is shining. But we need electrical light above all after sunset, and we need heating in winter. Although the sun can produce lots of electricity, it is not possible to store the surplus electricity from August for the gloomy days in February. A problem that cannot be solved? No, for this is where our multi-talent hydrogen comes into play ...
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