What is energy and which energy sources do we use?

We use energy  every day. When we switch on the light, charge our mobile phones, or cook, but also when we walk, cycle or travel by train. Energy is everywhere, in nature, in technology and in our bodies. Like us humans, plants and animals also need energy to develop. We cannot usually see, touch or feel energy. But we can perceive the effect of energy, for example when we feel the warmth of a candle or when we feel tired because we haven't had anything to eat.

So, energy is the ability to:

  • do mechanical work,
  • radiate light or
  • give off heat.

And energy is never lost! In a closed system, the total energy always remains the same, i.e. energy is only ever converted into another form, or it is stored. But the sum of energy in the system remains the same. This is also called the law of conservation of energy.

Source picture: Stock-Fotografie-ID:691864528

We can produce energy in different ways. For example, by burning fossil fuels such as coal, oil and gas. In doing so, we use the released energy mostly in the form of heat and electricity. However, this generated electricity is not climate-friendly, because carbon dioxide (CO2) is produced during combustion. Carbon dioxide (CO2) is a greenhouse gas that increases the anthropogenic (man-made) greenhouse effect and thus intensifies our climate crisis. Furthermore, by burning coal, oil and gas, we are also losing these finite resources forever. It is therefore crucial for our future to decide well about which energy sources we humans use to get energy for our everyday lives!

How much energy do we need?

To get enough energy to get through our day, say we need around 30 kWh (this will differ on lifestyle and location, but is a pretty good average across the EU). To get this, we would need to burn

  • 3 cubic metres of natural gas and release 6 kg of CO2 or
  • 3 litres of petroleum (or crude oil) and release 9 kg of CO2 or
  • almost 4 kilograms of hard coal and release as much as 11 kg of CO2