Solar Energy

Solar energy is the main natural source of energy from our nearest star, the sun.

Solar radiation is intercepted by the Earth in its rotation around it.

What is the solar energy?

This energy is the result of successive nuclear fusion reactions; and it gets to the earth in the form of photons.

Photovoltaic solar energy: This is the electricity produced by the transformation of one part of the radiations with a photoelectric cell

Thermal solar energy: This is the use of heat from solar radiation. The thermodynamic solar energy is a technique that uses thermal solar energy to generate electricity.

Passive solar energy: This is the oldest use of solar energy. It consists of getting direct benefit from the sun’s rays.

Direct exploitation of solar energy

1 Direct heating of buildings

This happens when solar energy is used directly, as in for example, greenhouses. Architectonical designs should be done in order to take advantage of it, and that way, save energy.

2 Accumulation of solar heat

We can accumulate solar heat by putting structures under the sun. The sun heats some fluids inside the panels. It is mainly used to heat water and it is usually placed on top of a roof where the sun’s rays go directly. We would save more than 5% of the energy consumed to heat water

3 Electricity Production

We can generate electricity using different methods:

Through the thermal system, where the energy is used to turn water into steam; this steam produces electricity in special devices, like turbines.Through photovoltaic panels, where the sun light converts directly into electricity thanks to the photoelectric effect.

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. They produce electricity from the light that they get. These panels are made of a semiconductor material (silicon). When these panels get the light, a small tension is generated (0.58 volts). In a series, the tension can get to 8V.

Solar energy does not generate direct pollution, but the collector systems have polluting substances that affect the environment.

Solar panels can be unsightly They can have an impact on the

microclimate, the fauna and flora of the area.

Emissions of powders and fluoride compounds may be very polluting in the production of the materials used for the solar panels

Solar resource is very abundant in Spain.

Spain is the fourth country in the world in solar energy technology. 80% of this is exported to Germany.

Since 1999 until 2004, 359,541 m2 of solar farms have been installed in Spain.

The biggest problem in the development of this kind of energy is the high initial cost of the installation.

Germany, Italy, Spain and the Czech Republic lead the list of solar photovoltaic energy installed in 20010 in the European Union.

At the end of 2010, the accumulative capacity installed of photovoltaic energy in the EU increased up to more than 28million MW, with a production of energy equivalent to the electricity consumption of about 10 million homes in Europe.

It is an ideal system to be installed in distant areas where it is not possible: To set up electric wiring To have a maintenance

staff (lighthouses on inaccessible coasts, buoys in dangerous seabed…)

The main challenge is the construction technique of the silicon wafers which are too complex and expensive.

Another one is the output and the space used; the final output is about 13%

According to an article in the magazine New Scientist, a new system of flexible solar panel, which will be on the market in 3 year’s time, will make it possible to manufacture clothes, recharge a mobile phone and complete other tasks.

A great advantage is its low price, and the manufacturing of it would be made in big rolls, so that one could cut the amount desired.

Engineers from Cincinnati University have developed a technique to transform solar energy in sugars.

This could be used to create biofuel with an increased, energetic power, removing carbon dioxide from the air and not affecting the crops

This advance was obtained analyzing a natural substance from a kind of tropical frogs and plants which take advantage of solar energy.