The phrase ‘fusion energy' or ‘nuclear fusion' seems like a daunting and complex term, but if you think about it in the correct way, it is really a very simple concept to understand.
The key word is fusion. It literally means to combine two things. The nuclear process of fusion is exactly that - it is the combining of two atoms to form a new atomic particle. Remember that everything at an atomic level is differentiated only by the number of electrons spinning around the center of an atom, and the number of balancing protons and neutrons in the center.
To understand fusion energy, keep the image of an atom in mind. If you combine an atom with 1 proton and 1 electron, with an atom that has 2 protons and 2 electrons, you will get an atom with 3 protons and 3 electrons. It is not really that simple, but you get the idea.
The forcing together of the atoms causes them to release a large amount of energy and also to shed electrons and other atomic particles. This fusion energy can be used to heat water that would turn a turbine and create electricity, just like a traditional fossil-fuel power plant.
Several factors have advocates and researchers very excited about fusion energy. The first advantage is that fusion uses hydrogen as fuel. This means a fusion plant will run mainly on water in some form. The half-life of the spent atomic particles is much less than that from traditional fission reactors (our modern-day nuclear power plants already in operation). Finally, generating fusion energy has a very small environmental impact and very safe operating parameters.
Unfortunately, we have not discovered a way to produce fusion energy efficiently enough for its widespread use. In order to force the atoms together, a very large amount of energy needs to be expended to create powerful magnetic and energy fields. The electricity used to create these fields can consume half of all the energy produced by the reaction.
There were rumors for a while about the discovery of a 'tabletop' or 'cold' fusion energy experiment, but the reaction that was recorded turned out to be energy neutral - meaning it produced no excess energy.
Researchers are still working hard on developing a way to deliver fusion energy to homes all around the world. The latest experiments involve a powerful laser that strips away parts of the atoms allowing small nuclear forces to draw them together.
Whether we will ever understand fusion energy thoroughly enough to harness its power remains to be seen.