Non Renewable Resources: Introduction and Examples

Key Concepts:

• Earth
• Natural resources
• Renewable resources
• Non-renewable resources

Introduction: 

Humans depend on natural resources because humans use natural resources as a source of energy and raw materials to make products. Food is a natural resource that can be consumed in its natural state or processed form. There are two types of natural resources – renewable and non-renewable. We should use natural resources carefully so the supply will last longer. 

There are many of Earth’s resources that are used to generate energy. Energy is used for many purposes such as transportation, manufacturing, construction, etc. Energy resources that are present in limited amounts and cannot be replaced easily once they are used are called non-renewable resources. 

Non-renewable resources used in the construction of houses are roofing material, plumbing, work material, electrical fixtures, etc. 

We all depend on Earth’s land, ocean, atmosphere, and biosphere for many different resources. 

Non-renewable resources are those natural resources that are exhausted more quickly than they can regenerate. Fossil fuels such as oil and natural gas take millions of years to form. Non-renewable resources are gone forever once they are extracted and used completely. 

Some common examples of non-renewable resources include: 

• Fossil fuels (coal, oil, natural gas) 
• Diamonds and other precious gems and minerals 
• Types of metals and ores 

Energy Resources – Fossil Fuels 

Some of the very important non-renewable resources are buried present within the Earth’s crust. These natural resources are coal, petroleum, and natural gas. These are formed from the remains of living things. So, these natural resources have an organic origin, and hence coal, petroleum and natural gas are called fossil fuels. Fossil fuels primarily consist of compounds of carbon and hydrogen and are called hydrocarbons. These compounds contain stored energy that is obtained from sunlight by plants and animals that lived many years ago. When these hydrocarbons are burned, chemical bonds form and energy is released in the form of heat and light. Most of the energy used by human beings is obtained from the burning of fossil fuels. 

Coal Formation 

Coal is the most burned fossil fuel. Millions of years ago, coal was formed when the Earth was covered with vast marshy forests where plants such as giant ferns, reeds and mosses grew. When these plants grew, some of the plants died and fell into the swampy waters. New plants grew up to take the places of old plants, and when these plants died, still more new plants grew. In this process, there was a very thick layer of dead plants decaying in the swamp. When the surface of the Earth changed, water, dirt, and dust washed in and stopped the process of decaying. Again, more plants grew up, and they also died over a period and fell to form separate layers. Like this, after millions of years, the formation of many layers took place, one on top of the other. This causes the weight of the top layers, water, and dirt, the lower layers of plant matter. Heat and pressure-produced physical and chemical changes occur in plant layers due to the production of heat and pressure, which forces out oxygen and leaves rich carbon deposits. So, the material that had been plants became coal. 

The four stages in the formation of coal are peat, lignite, bituminous, and anthracite. These stages depend upon the conditions in which plant remains are exposed after they were buried. – the greater the pressure and heat, the higher the quality of coal. High quality coal is denser and comprises less moisture, gases and has a higher heat value than lower-quality coal. 

Coal is described as a readily combustible rock consisting of more than 50% by weight of carbon. The other constituents of coal contain hydrogen, oxygen, nitrogen, ash, and sulphur. The undesirable chemical constituent of coal includes chlorine and sodium. In the process of conversion (carbonization), peat is converted to lignite; lignite is converted to sub-bituminous, sub-bituminous coal is converted to bituminous coal, and bituminous coal is finally converted to anthracite. 

Peat: It is the first step in the formation of coal. The incomplete destruction of organic matter leads to the formation of peat. Peat contains large amounts of water, and hence it needs to be dried before using it. Peat burns with long flame and smoke. 

Lignite – It is the second step in the formation of coal. It is the lowest quality of coal. It means that it has the lowest heating value and the least carbon content. 

Bituminous – It is the third step in the formation of coal. It is intermediate in quality and is sometimes called soft coal. It has many layers. It is the most abundant kind of coal and consists of 80% carbon. Its heating value is high, and it also has a high amount of sulphur. 

Anthracite – It is the fourth step in the formation of coal. It is the highest quality of coal, which means that it has the highest heating value and highest (90%) carbon content. Anthracite is very hard, deep black, and looks almost metallic. It is also called hard coal. Due to the highest carbon content, anthracite burns longer, with more heat and with less dust and soot as compared to other types of coal. 

Formation of Petroleum and Natural Gas 

When plants and micro-organisms died in prehistoric oceans and lakes, their bodies piled up on the ocean floor and at the bottom of the lakes. These were all buried by sediments. As time passed, more sediments got piled up, and hence heat and pressure increased. This heat and pressure cause chemical changes over a period of time to convert the remains of organic material into petroleum and natural gas. 

Natural gas and petroleum are hydrocarbons. Petroleum is also called oil, made up of liquid hydrocarbons. Natural gas is made up of hydrocarbons in gaseous form.  

Petroleum and Natural Gas Deposits 

These two are very important sources of energy for transportation, industries, and farming. Due to their importance, petroleum and natural gas deposits are very valuable and are mined from permeable sedimentary rock. Permeable rocks have interconnected spaces. From these spaces, the liquids can move easily. Pressure increases when sediments accumulate and sedimentary rocks form. This increased pressure pushed fluids such as petroleum and natural gas to move out of the spaces and through the spaces and upward through the layers of permeable rocks. The fluids move in an upward direction until it reaches a layer of impermeable rock through which liquids cannot pass or flow and are called cap rock. Petroleum which accumulates under the cap rock fills all the pores to form an oil reservoir. As we know, petroleum is less dense than water; it rises above trapped water. Natural gas rises above petroleum because natural gas is less dense than water and oil. 

Oil Traps 

Geologists look at the Earth’s crust to find out the types of rock structures that may trap oil or gas. When a well is drilled in an oil reservoir, the petroleum and natural gas flow to the surface of the Earth. When the pressure of the covering rock is removed, fluids rise up and come out through the well. 

  Fig. No. 6: Oil traps 

Uses of Fossil Fuels 

Fossil fuels, such as minerals, oil, and natural gas are non-renewable resources. Throughout the world, fossil fuels are the main source of energy. Unrefined petroleum (Crude oil) is used in the production of synthetic fabrics, plastics, medicines, waxes, insecticides, detergents, fertilizers, shampoos, etc. 

Coal is present in large amounts throughout the world. Every continent has coal, but almost two-thirds of coal deposits are present in the USA, China, and Russia. 

Summary

• Humans use natural resources as sources of energy.
• There are two types of natural resources – renewable and non-renewable.
• Resources that can be replaced within a human life span or whenever they are used is called renewable resources. Examples: Wind, water, solar energy, nuclear energy, biomass energy, etc.
• Geothermal energy is the energy from the heat of Earth’s interior.
• Sun is the source of renewable energy.
• Renewable energy is generated from tides.
• Biomass is a renewable energy resource that is obtained from plant material, sawdust, organic matter, paper waste, kitchen waste, etc.
• Wind turbines use the energy generated by converting wind energy into mechanical energy by the movement.