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CyberDodo and solar energy (1-45)

The sun – how to use it? 2/2

Thermal solar energy

One of the best known examples of this is solar water heating panels which are installed on many roofs and in which heat transfer fluid circulates these panels will go on to cover all or part of the water heating needs of a home.

Another very common use is in solar cookers (also known as solar ovens) which facilitate the cooking or heating of food with only the use of solar energy. This device, both simple and inexpensive, has yet another benefit that of conserving our forests since local populations no longer need to cut down trees in order to prepare their meals.

More sophisticated technologies are also being explored, such as solar power installations in which water vapor produced by solar radiation turns turbines which generate electricity.

It would be impossible to not mention single flow upwind systems. The idea is very simple on paper one creates a vast spherical zone of greenhouses (several hundreds of hectares) which the sun then heat up. At the centre, a chimney several hundred metres high is built (in certain projects, it reaches thousands of metres). Given the temperature difference between the air in the greenhouses and in the tip of the system's tower, a phenomenon of air circulation is produced, which is enough to warrant the installation of turbines at the base of the chimney in order to produce electricity.

Only time will tell whether this technology will be able to be transferred from engineers' computer screens to reality...

Create electricity using only the sun

Photovoltaics

In contrast to thermal solar panels which heat stored water, photovoltaics directly produce electricity. In theory, they represent an ideal solution to replace fossil fuels since they produce neither pollutants nor greenhouse gas emissions. Nor do they disturb the environment in which they are installed, require practically no maintenance and need only be connected to a converter in order for electricity to be obtained.

Why aren't photovoltaics installed everywhere ?

Unfortunately, several issues must still be addressed in order for this solution to be implementable, in particular : they are still expensive, their efficiency is limited and notably, they only produce electricity during the daytime. In order to have permanent availability, it would be necessary to use batteries (which is unfeasible in terms of cost), or to create globally interconnected networks so that the part of the earth illuminated by the sun provides electricity to those experiencing nighttime, or even invent independent systems which are capable of storing energy during the daytime for later use during darkness.

Photovoltaic energy will nonetheless be a primary player among alternative energies because it allows us to reduce our dependence on fossil fuels and, as such contributes to our fight against global warming. Numerous governments have established financial aid schemes in order to make solar energy more attractive than other more polluting energies.

A few concluding remarks :

To explain the slowness with which different forms of solar energy are being developed, the argument of their high cost is often invoked. However, it should be noted that many specialists estimate that if the real total cost of the use of fossil fuels was calculated (not only extraction, transformation and transport, but also irrevocable environmental damage and repair, including that of future sources) solar energy becomes a competitive option.

Let's not forget that in just one day, our planet receives more than enough solar energy to supply man's consumption needs for an entire year !

So let's do away with the age of fossil energy as quickly as possible and enter into the age of renewable energy with the Sun as our main inspiration !

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