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 sources 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 for 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. Resources that can be replaced within a human life span or whenever they are used are called renewable resources. Examples: Wind, water, solar energy, nuclear energy, biomass energy, etc. 

Energy Resources – Geothermal Energy 

In many locations, water flows underneath Earth’s surface. This water may flow through rock that becomes hot by nearby magma or by hot gases that are released by magma.  

So, the flowing water becomes hot as it flows through the rock. The hot water or the steam released from hot water is the source of heat energy called geothermal energy. Geothermal energy is the energy from the heat of Earth’s interior. 

Scientists have channeled geothermal energy by drilling wells to reach the hot water. Sometimes, if water does not flow through the channels, then water is first pumped down into the hot rocks. Then steam and hot water flowing from the channels can be used as a source of heat. It is also used as a source of power to run turbines that generate electricity. 

Solar Energy 

Sun is the source of renewable energy. For every 15 mins, Earth receives solar energy to meet the energy needs of people in the world for a year. Solar energy is the energy received from the sun. The main challenge for scientists is to capture the solar energy reaching the Earth. Sunshine can be converted into heat energy by two methods – passive system and active system. 

Passive system: Windows in the house facing the sun collects solar energy by the passive system. It is a passive system because this system does not use any moving parts. Here sunlight enters the house and warms the building materials such as bricks, cement, etc., which stores heat energy for the evening.  

Active system: This system uses solar collectors. One type of solar collector is a box with a glass top. This box is generally kept on the roof of a building. There are tubes within the box through which water circulates. The water gets heated by solar energy as it moves through the tubes, which gives heat and hot water. On cloudy days, there may not be enough sunlight for water heating. So, in such cases, the system uses stored heat energy from the previous day. 

Photovoltaic cells are an active system that converts solar energy into electric energy or electricity. Photovoltaic cells are good for small gadgets such as calculators.  

Energy from Moving Water 

Moving water is the oldest source of energy. Energy can be obtained from running water of rivers, streams or from ocean tides. Today 6% of electricity in the USA is generated from hydroelectric plants. At hydroelectric plants, a dam holds running water and channelizes the water through the plant. Inside the plant, due to the force of water, turbines rotate and turn generators that result in the production of electricity.  

Another source of renewable energy that is generated from moving water is tides. Tides are the rise and fall movement of seawater at certain times of the day. To make use of tidal flow, people have constructed dams to block the water at the time of high tide and then release the water at low tide. When the water is released, the turbines rotate within the dams.  

Energy from Biomass 

Biomass is a renewable energy resource that is obtained from plant material, sawdust, organic matter, paper waste, kitchen waste, etc. Biomass is the main energy source in many developing countries. Many trees are cut down and are used as fuel for cooking, heating water, etc. Micro-organisms such as bacteria decompose the organic matter and produce gases such as methane, which is also used as a fuel. Liquid fuels such as ethanol are also formed by the action of bacteria on biomass. All these given resources can be burned to create electricity. 

Energy from wind 

The wind is a source of renewable energy. The movement of air over Earth’s surface is called wind. The difference in air pressure caused by the sun’s uneven heating of Earth’s surface results in the formation of wind. Wind turbines use the energy generated by converting wind energy into mechanical energy by the movement of air to produce electricity.     

Nowadays, wind energy is used to produce electricity in locations with the constant wind flow. Small wind-driven generators are used to fulfil the energy demands of individual homes. Wind farms contain many wind turbines to produce sufficient energy to meet the electricity demands of the whole community. But these wind generators are not practical everywhere, even in the locations such as windy mountains where the wind does not blow constantly. Because there is no constant flow of wind, we cannot depend on wind energy as the only source for many locations. 

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