Why is Solar Energy so amazing?
Sunlight consists of tiny particles of pure energy - so called photons.
Every second our sun emits billions of these photons travelling so fast that they can reach Earth in less than 8 minutes. When these particles hit the ground they convert most of their energy into heat.
Our plants manage to use one
in hundred particles for growing. These plants as well as the
animals who eat these plants or other animals represent our food resource.
In order to produce electricity we usually burn these plants in form of wood, oil or coal with an efficiency of typically less than 50%. Hence, less than 1/2 in 100 photons is used to generate electricity. Moreover, combustion always produces harmful gases like co2 - which is responsible for global warming and the current and future climate changes.
There are more efficient and less harmful methods to generate electricity:
- Solar collectors
- Photons from the sun are particularly efficient to use for heating e.g. water. Solar collectors are devices that are designed for maximum absorption of light to produce hot water. More than 60 in 100 photons can be used, making solar collectors very useful and economically - even in colder countries like Sweden.
- Solar cells
- A solar cell typcially converts 10 in 100 photons into electric power
(some more than 20!). The entire convertion happens in absolute silence
with no moving parts and no exhaust pipe! Think what a turbine or a
diesel engine does!
Both solar collectors and solar cells work absolutely silently, without
harmful waste products or the need to transport the energy to the power
plant. Let us think.. photons are pure energy and get delivered
for free!
In fact there are many more techniques to utilise the sun's energy which
are also less harmful than combustion - although they are not be quite
as efficient as the direct conversion using solar cells and solar collectors:
- Wind power
- By using wind turbines we can also generate electricity. Wind or moving airmass itself is a result of hot air moving up from Earth's surface.
- River Power
-
Water that has been lifted many kilometers into the sky through evaporation can be used to generate electric power. Rain on hills and mountains supplies water for the rivers using water turbines in hydropower plants.
- Ocean power
- Our oceans contain energy of various types. Heat differences between the surface and deeper regions or the energy of wave movements can be exploited to produce electricity using the heating photons or the sun's (and the moon's) gravitational forces.
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