Net energy gain

Alright kiddo, so when we talk about net energy gain, we mean how much more energy we get out of something compared to how much energy we put into it.

Let's say you want to use a toy car to move a toy block. You need to use your hand to push the car, which takes energy. But if the car can move the block, then you've gained energy overall!

Now, when we talk about net energy gain on a bigger scale, like with fuels or power plants, things can get a bit more complicated.

When we burn fuel in a power plant, we need to put in some energy to start the process - like lighting a match to start a fire. But if the fuel can generate enough energy to power the plant and some extra left over, then we have a net energy gain.

It's important to think about net energy gain when we're trying to figure out which energy sources are the most efficient and sustainable. High net energy gain means we're getting more out of our energy sources so we can keep using them without running out too quickly.