In Quantum Mechanics, there is a phenomenon called Quantum Tunneling. This is where a particle "tunnels" through a "barrier". I know you're probably saying, Dan! Why should we car about this??? well listen up, and I'll tell you.
This is important because this explains the nuclear fusion that occurs in the main sequence stars like the sun. Normally nuclear fusion requires a lot of energy to get these particles to collide but quantum tunneling uses a lot less energy. Quantum tunneling is very rare in stars like the sun, but the sun is so massive that the shear number of collisions make quantum tunneling very noticeable.
If we can find a way to make quantum tunneling much more frequent, we can effectively use nuclear fusion to create energy. This energy from nuclear fusion can help replace our reliance on fossil fuels. There aren't harmful byproducts from nuclear fusion so we can create a substantial amount of energy cleanly and effectively.
^^^^That is a good video that helps explain the basics of Quantum Tunneling if you want a visual representation or a different explanation