Types of Energy

Almost every natural and human-made activity is somewhere connected to energy. It is found in many things, either it's living or non-living. Due to such broad coverage, there are different types of energy. In particular, it usually takes different forms.

In this article, we are discussing the various types of energy. We also highlight the aggregate types and definitions of each type. Before we discuss the different types of energy, let's understand the definition of energy:

What is Energy?

According to a definition, energy refers to the capacity of a physical system that allows it to do some work. However, it is important to note that it does not mean that it is necessarily available to work just because energy is present. More specifically, energy is the ability to perform work. In physics, energy refers to a quantitative property and should be transferred to an object to perform work. That is the reason it is most commonly defined as the strength that helps to perform physical activities. Energy is the scalar quantity, and the SI unit of energy is measured in newton-meter (N*m) or Joule.

In biology, energy is defined as the ability to cause some change. Energy has an important role in life and for organisms. All organisms on earth use different energy forms to perform biological processes that ultimately help them grow and survive. Generally, organisms require the most energy, which is converted into heat for their use. The Sun is, directly or indirectly, the primary source of energy on earth.

Note: According to the Law of Conservation of Energy, "the energy can neither be created nor destroyed; it can only be transformed from one state to another. As a result, the total energy of a system remains constant."

Types of Energy

Although there are various types of energy, it is broadly categorized into the following two forms:

• Kinetic Energy (the energy of motion)
• Potential Energy (the energy of an object due to its position or structure)

Let's understand more about each type:

What is Kinetic Energy?

When there is an object in motion, there will be the energy associated with the object. Such a kind of energy associated with any object in motion is known as kinetic energy. When an object is in motion, it is capable of causing some changes or is capable of doing work on its own.

To understand this, let us consider a wrecking ball. When it is in motion, it can cause a lot of damage, even if it moves slowly. It is used to perform works like the demolition of houses, building, stones, etc. Besides, when a wrecking ball is not in motion, it does not perform any work and has no kinetic energy. Other common examples of kinetic energy include a walking organism, a speeding bullet, a swinging pendulum, electromagnetic radiation like sunlight, the rapid movement of molecules in the air producing heats, etc.

Sometimes, the kinetic energy is also referred to as thermal energy. The higher the amount of thermal energy, the higher the kinetic energy of atomic motion, and vice-versa. The average thermal energy of multiple molecules in a combined form is known as the temperature. When the thermal energy is being transferred from one object to another, it is referred to as heat.

The formula of Kinetic Energy is defined as below:

Where,

m indicates the mass of the object.

v indicates the velocity of the object.

Types of Kinetic Energy

The following are some types of kinetic energy that are particularly important because of their usage:

• Radiant Energy: Radiant energy is the type of electromagnetic energy that travels in transverse waves. It is commonly experienced as heat. It can be either visible waves (e.g., light energy) or invisible waves (e.g., X-rays, radio waves, etc.). Suppose that we turn on an incandescent light-bulb; it usually produces two different forms of energy, such as visible light and heat. Both these forms of energy are radiant energy.
  Another popular example of radiant energy is sunlight, which helps generate fuel and warmth to make life possible on earth.
• Thermal Energy: Thermal energy is similar to radiant energy in some way. Humans commonly experience it as heat or warmth. This type of energy mainly generates by the movement of atoms and molecules in any substance. The faster the particles travel, the more heat is produced. When moving rapidly, atoms and molecules collide with each other, producing heat energy or thermal energy. While radiant energy refers to waves or particles, thermal energy refers to the activity level between atoms and molecules in a substance.
  Geothermal energy is the most common example of thermal energy on earth. It arises from the decay of the earth's natural minerals and volcanic activities. Typically, thermal energy is the reason we feel something hot or cold. Similarly, we can use solar radiation for cooking food.
• Sound Energy: Sound is defined as energy movement through a substance (e.g., air or water) in longitudinal (compression/rarefaction) waves. A sound is usually produced when an object or substance vibrates due to a force. When such vibrations reach human ears, they are experienced as a sound. The disturbances move in waves through different mediums (such as solids, liquids, and gases) and reach the human ear, further converted into electrical signals by eardrums. These electrical signals are identified and interpreted as sensations of sound by the brain.
  Sound energy is considered small when compared with other types of energy. However, it can cause potential damage if it increases to some uncertain extent. Besides, it cannot travel through a vacuum because there are no atoms to transmit vibrations.
• Electrical Energy: Electrical energy is formed by the moving electric charges, called electrons. The faster the charged particles move, the higher the electrical energy they will carry. The flow of negatively charged particles around a circuit produces electricity. They are usually carried through wires. Electricity, batteries, and even electric eels are common examples of electrical energy in nature.
  Electrical energy (electricity in general) is a well-known form of energy and popular in the built environment for the ubiquitously developed world. This form of energy is delivered in currents and is driven by the voltage across the load (or resistance).
• Motion Energy: Motion energy is a type of energy stored in the motion of objects or moving objects. The faster the objects move, the higher is the energy stored in them. Specifically, energy is taken by an object for a motion and released when an object slows down. The most common example of motion energy is the wind in nature. Another example can be defined as a car accident, where a car stops immediately and releases all its motion energy in an uncontrolled way at once. The higher the car's speed, the higher the motion energy and thus, the greater the damage.
• Mechanical Kinetic Energy: Mechanical kinetic energy refers to the energy that a substance or a system has associated with because of its motion. In particular, it is usually associated with the mechanical movements of objects. A common example of this energy include machines that use mechanical energy to work.
  The amount of energy directly depends on the mass and velocity of the moving object or a system. This means that objects with higher mass or higher velocity will have higher mechanical kinetic energy.

What is Potential Energy?

Potential energy is the second type of energy. It is the energy that has stored potential in an object or system of objects and can be used further. In particular, the potential energy is associated with objects because of their position or structure.

To understand this, let us again think of a wrecking ball. As we said above, when a wrecking ball is not in motion, it does not have kinetic energy. Suppose it is lifted two stories above any vehicle and suspended on a vehicle from there. Although the suspended wrecking ball is not moving, it does have an energy that can cause damage to the vehicle. In this case, the wrecking ball has energy because it has the potential to do work (in this case, damage). It is the potential energy that makes it possible for that object to function in a particular state. Other potential energy examples include a person skydiving out of an airplane and water-energy placed behind a dam.

Potential energy can convert kinetic energy into a more obvious form. For instance, there is potential energy in the water behind a dam. Besides, flowing water, such as a waterfall or fast-flowing river, has kinetic energy.

The formula for the Potential Energy is defined as below:

Where,

m refers to the mass of the object in Kg (Kilograms).

g refers to acceleration due to gravity.

h refers to the height in meters.

Types of Potential Energy

The following are some types of potential energy that are particularly important because of their usage:

• Chemical Energy: Chemical energy refers to the energy stored in chemical bonds of substances, such as atoms or molecules. Because energy is stored; therefore, it is a form of potential energy. The chemical energy is usually released as heat when a chemical reaction takes place. Additionally, the substance is converted into a whole new substance after the release of the chemical energy. This type of energy can be absorbed and released due to changes in certain species' particle number.
  Chemical energy is currently the most used type of energy in the world. Some chemical energy examples include petroleum, fuels, natural gases, batteries, coal, biomass, etc. Chemical energy is transformed into thermal energy when burning wood in a chimney or gasoline in a car engine. During combustion, the fuel burns and chemical bonds break, releasing heat. The energy level of fuel mainly depends on the molecules' mass, structure, and other properties. Chemical energy is known for around 85% of worldwide energy consumption in the form of fossil fuels (e.g., petroleum, coal, natural gases, etc.) and bioenergy (e.g., alcohol, wood, straw and cow dung).
• Gravitational Energy: Gravitational energy is a type of potential energy associated with gravity, meaning that the energy is stored due to the object's height or substance. The higher and heavier the substance, the more gravitational energy it will store. For example, the book placed on a table will have more gravitational energy than the book placed on the earth's surface. The most common example of gravitational energy is the water flowing down from a waterfall.
• Nuclear Energy: Nuclear energy is the energy that is stored inside each atom of the nucleus and holds the nucleus together. A very large amount of nuclear energy is released when the nuclei are combined (known as fusion) or split apart (known as fission). The fission method is a widely used way of producing nuclear energy. Nuclear plants radioactive element uranium during the fission method to produce electricity.
  During nuclear reactions, the mass volume decreases, resulting in a release of significant amounts of energy. Although nuclear sources are a widely used method for generating electricity, the problem of safe disposal of radioactive waste still exists.
• Electric Potential Energy: Electric potential energy is usually defined as the energy required to move a charge against an electric field. Some common examples of this energy include a television before it is powered on, an incandescent light bulb that has been switched off, a black-light turned off, and a radio tower that is not working.
• Elastic Potential Energy: Mechanical potential energy refers to the energy stored in an object due to tension. This means that the energy is stored in an object when a temporary strain is applied to it. This type of energy is only stored until the force is entirely removed and the object comes back to its normal shape. Energy is stored in bonds between atoms.
  The most common examples of this energy type include a stretched rubber band or elastic band and compressed springs. Deformation may involve compressing, pulling, or twisting any of these objects. Sometimes, this energy is also called mechanical potential energy.

Note: Mechanical energy is typically a sum of both the kinetic energy and the potential energy of an object.

Energy Resources

Energy resources are commonly used as fuels in machinery, automobiles, and industries. They are also used for power generation in thermal plants. In particular, there are various energy-resources. However, all energy resources are summarized under the following two types:

Renewable Resources: Resources that are renewable or continuous are called renewable resources of energy. This may include natural resources such as solar, water, wind, geothermal, etc. These resources come from sources (or origin) that can bring them back. Therefore, even though organisms consume these resources, they still exist continuously in nature.

Non-renewable Resources: Resources that are not renewable are known as the non-renewable energy resource. This may include resources such as natural gas, oil, coal etc. After the consumption of these resources, they cannot be renewed by natural processes or activities.

The main types of energy are solar, wind, oil, wood, coal, nuclear, hydrogen, hydropower, bio-energy, geothermal, and natural gas, based on different energy resources.