What is energy?

16 August 2022

What is energy? Energy is a measure of the work required to set something in motion.

Welcome to SenseNode's energy school! Here we highlight topics related to energy. So what is energy?

Energy is a measure of the work required to set something in motion. Energy is everywhere around us, partly in stored form, so-called positional energy, and in transferred form in connection with movement, so-called kinetic energy. Energy is measured in joules. But there are also other measurements that refer to energy, such as calories and watt hours.

Read more about how you can energy efficiency here.

Different types of energy forms

There are different types of energy forms and all of these have slightly different definitions. There is simply no universal definition of energy. This is because, for example, mechanical energy is not the same as electrical energy.


Mechanical energy means forms of energy such as kinetic energy and positional energy. In simple terms, potential energy is defined as the work required to move an object to a new position. You might remember from physics lessons at school that the teacher was harping on about how energy doesn't disappear, it just changes form? This is described in what is called the energy principle where the conservation laws are included.


The world's most famous formula, E=m², is about energy. It was developed by Einstein to describe the relationship between the energy of a body and its mass, as well as the speed of light. Simply put, the formula describes how much energy it takes to move a body. As the speed approaches the speed of light, the mass becomes so great that extreme amounts of energy are required. This shows in a simple way why we cannot travel faster than light. It would simply take an infinite amount of energy to move us at such a speed.

Advantages of hydropower

Energy can be extracted in many different ways. In order for us humans to extract and use energy, we need so-called energy carriers. An example of an energy carrier is electricity. As said, energy cannot be created, but only transformed. Therefore, we humans need to find ways to extract the energy from something and then, via electricity for example, make sure we can transfer it to a machine, a lamp or whatever it may be that needs power.

An example of this is the wind. In the winds there is energy, which we humans can capture via wind turbines and then convert into electrical energy. In this way, we can move the energy from the wind to, for example, our street lighting.

Energy is difficult to store. Batteries can store energy in the form of electricity. But most of the energy extracted needs to be used directly. This means that you need to extract energy constantly and always ensure that there is electrical voltage in the lines. This is done by using several different energy sources, such as hydropower, nuclear power and wind power.

Have you heard of Industry 4.0?

What is electrical energy?

Electrical energy is a measure of electrical charges. Simply put, it describes the work needed to move the electric charges to a certain point. Just like energy in general, electrical energy is measured in joules. But another common measure is also the watt second. A watt second is actually a joule. However, a watt second is rather impractical to use, as it becomes very large numbers. Therefore, it is more common to use watt hours and also kilowatt hours.

Electrical energy exists in nature

Electrical energy exists in nature and we see it in the form of thunderstorms and lightning. Since man learned to handle electricity and use it in everyday life, it has become the primary source of energy for lighting, household, heating, and more.

We extract electrical energy by converting mechanical energy into electricity. Energy cannot be created but only transformed. Therefore, we need a primary energy source to be able to extract electricity. It could, for example, be about hydropower, wind power or nuclear power.

Electric power plants are designed to extract electrical energy. It is common to build hydroelectric power plants by rivers and streams, in order to be able to capture the kinetic energy in the water and, via turbines, make a generator spin, which in turn produces electrical energy.

A wind turbine works in a similar way, but instead it is the wind that makes the generator spin and generate electricity.

Boats wind power and hydroelectric are examples of so-called renewable energy sources. This means that these energy sources do not contribute to any emissions of greenhouse gases or other waste that needs to be managed.

Nuclear power on the other hand, is a bit more debated as the process itself creates a nuclear waste that needs to be managed. Right now, such waste is placed in large mountain deposits, where they are buried to lie there for several thousand years. Then a moral question immediately arises regarding our possible right to leave waste to our future offspring.

Nuclear power is also associated with a certain risk when it comes to operation. An accident at a nuclear power plant can have devastating consequences, as we have seen in previous disasters. Therefore, there is currently a lot of research going on into what is usually called Fourth Generation Nuclear Power. The vision is to be able to extract electrical energy via nuclear power but without having to deal with waste that is radioactive for several thousand years. The facilities themselves must also be designed so that accidents cannot occur with the consequences we have seen before.

Electrical energy is used by all people all over the world and is a prerequisite for keeping our modern society going. Do you want to know more about SenseNodes technology, read more here.

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