Classification of Raw Materials and Global Energy Sources

Raw Materials and Industrial Inputs

These resources are offered by nature and are processed by industry to turn them into finished products. Depending on their source, raw materials can be classified into:

Classification of Raw Materials

• Mineral Raw Materials

  These are part of the Earth's crust. They are extracted from underground mines, which can be subterranean or open pit. Minerals can be classified as metallic (from which metals are extracted), non-metallic, and energy minerals (which provide energy sources).

• Vegetable Raw Materials

  Examples include food products, forest products, and rubber.

• Animal Raw Materials

  Examples include wool, hides, and fish.

Sources of Energy

Energy sources are mainly divided into two groups:

• Non-renewable energy sources: These can become depleted because the time needed for them to form requires hundreds of millions of years. They cannot recover at the rate of current use (e.g., coal, oil, gas).
• Renewable energy sources: These are practically inexhaustible because they are constantly renewing or are perpetually present (e.g., sun, wind).

Key Non-Renewable Energy Sources

• Coal

  Formed from fossilized forests. It has a large heat capacity and is still used today in the steel industry and power plants. It is highly contaminating. Its use tends to decrease as much as possible.

• Oil (Petroleum)

  It is a black liquid of viscous consistency derived from organic waste. It is absolutely essential today, not only as an energy source but also as a raw material for obtaining a large number of chemical industry products. It is not used directly; it requires a series of processes in refineries to obtain various products.

• Natural Gas

  Found in underground pockets. There are large reserves, and its price is relatively cheap. Therefore, it is an energy source that is gaining importance.

Major Renewable Energy Sources

• Hydropower

  Leverages the power of water to move turbines that generate electricity. It is a clean energy source, although the necessary dams transform the natural landscape and sometimes displace human populations.

• Wind Energy (Aeolian)

  Leverages the power of wind to move a propeller that transmits motion to a turbine, generating electricity. It represents a small percentage of current electricity consumption and depends on variations in wind intensity.

• Tidal Power

  Uses the force of waves and tides. Its use is very limited.

• Solar Energy

  Uses light and energy from the sun. It is being tested and used in countries with abundant sunshine, especially for domestic consumption.

• Geothermal Energy

  Uses heat from inside the Earth. Its use is geographically limited, relying on areas where this heat emerges naturally.

• Biomass

  Produced by the fermentation of plant masses. The bacteria that cause decomposition produce gases (methane and ethane) used as fuels. Certain plants are also used to produce an alcohol (bioethanol) that is used as fuel.