19
Using renewable
energies
1.C4T1 2.C4T1 3.C4T1
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C4M1
4. Rajasthan in India: Camels transporting solar panels. Solar panels can be installed and used wherever there is enough sun.
Madanjeet Singh / UNESCO
Technological Innovations

Development can only be sustainable if it is founded on scientific and technical knowledge. The latest technological advances can provide solutions to desertification by improving on traditional systems of production combined with the use of new sources of energy that progressively restore the soil, increase cereal and meat production and prevent environmental degradation.

Substituting wood
All human societies use energy, which is vital for its proper functioning and development. Today, however, a large number of populations use wood as their major source of energy, which contributes further to desertification (through deforestation) and increases the greenhouse effect (by releasing carbon dioxide).
The non-sustainable use of forest resources (firewood) as a source of energy is a factor leading to desertification. Therefore, identifying and employing alternative renewable energy sources is important in the fight against desertification.
Non-polluting and infinite or renewable energies can replace wood at limited or no cost (the energy source is free) and they can easily be used by families in villages.

Solar energy
Bright sunny conditions, characteristic of arid and semi-arid regions, can satisfy energy needs in these areas.
Solar energy can be used in multiple ways:

C1M2
5. Wind energy produces electricity without harmful effects to the environment.
5. © Michel Le Berre

Wind
The force of the wind can drive wind propellers that produce electricity. A large rudder orientates the wheel so that it faces the wind, while a small blade reduces the speed of the wheel during strong winds.
The rotational movement made by the wind produces both electricity and mechanical force. The wind energy can generate a pump to extract water from wells, fill watering holes or irrigation basins or activate mills to transform grain into flour (windmill).
In California, North America, the production of electricity from wind power has reached industrial proportions. In the drylands where winds are frequent (trade winds, harmattan, scirroco), this form of energy could be an important complement in the long term. This type of energy will facilitate land irrigation and the supply of water to the livestock.

Biogas
Biogas is a gaseous mix produced in a fermentation tank (airtight reservoir) or a digestor that derives from the decomposition of organic matter (dung and plant waste). The process of fermentation, that removes odours and pollution from the treated matter, lasts between 1 and 3 weeks and the biogas produced accumulates in the reservoir. The residues from the fermentation can be used as natural fertilizer (compost). The high temperatures in the drylands are beneficial to the creation of biogas. Its advantages: it is uncostly and can be used for lighting, cooking or to drive motors (generators, tractors and cars). Biogas can also be produced in small installations. This technique can most effectively be developed in regions where agriculture and cattle rearing coexist.

activities

pencil

Compile a list of the different types of energy sources found in your village: wood, wind, sun, petrol, gas etc.

Which energy type does your family mostly use? Why?

Is it the most economic or environmentally friendly form of energy?

pencil

Contact a company that specializes in renewable energies and ask them to make a presentation of their products during the school exhibition on desertification.

Invite all the villagers to the meeting.

smile

Construct a windmill.

To do this, take a square sheet of paper and fold it diagonally.

Cut along 2/3 of the diagonal from the edge of the sheet. You now have two corners for each angle.

Fold one of the corners and position it at the centre of the square, repeat this with the four alternate tips.

Then fix the four tips at the centre of the square with a pin attached to a wooden stick, this will act as a support handle.

smile

Construct a ‘windspeed tester’ by attaching four plastic cups at the extremities of two branches or rods in the shape of a cross that rotates on its axis.

Notice the speed of the rotation of the cross (the number of rotations per minute) in areas exposed to the wind and sheltered from the wind.

Explain how windspeed affects the environment.


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