Suppose energy becomes free and unlimited (not literally, but in a sense say that fusion is discovered). And suppose that energy via fusion is so easy to make that they literally hand out fusion devices on the streets for free and the whole world had free energy from now on.
How would the world change?
How would the society change, as in, petroleum and fuel companies would cease to exist, what will they base their focus on? Energy transfer companies would die out, as you'd have a device in your yard, and literally everywhere else powering your needs.
What would be the main consequence of this discovery and the world after it?
How would science advance, having not to worry about energy ever again? What would the first next big scientific breakthrough or engineering wonder come to life, considering energy is not holding it down anymore?
>Suppose energy becomes free and unlimited
That is akin to saying that entropy will be reversed. The tranformation and transmission of energy ALWAYS requires work, therefore it cannot be "free".
You would basically be able to do intensive agriculture day and night, vertically or diagonally.
You would be able to illuminate more parts of the world, cooking your food would be free as for everyone else, free heat, free transport - it's all good things.
"Free" is a flexible word I guess. You could say if you stole candy from a supermarket that it was free, but it really was not free, you had to consume caloric energy to get off your ass and walk there or drive there. There is no such thing as free energy within a confined measurable system if I'm not mistaken. However the Universe is very big, I'm sure there are a lot of sources of energy we may "borrow" from that we have not discovered how to do properly or efficiently, yet. Though said energy sources wouldn't be free they would certainly be far more abundant.
Supposing that fusion energy became prevalent, I think we would see a expansion in water desalinization projects, in the construction of co2 scrubbers that would condense atmospheric co2 into a form that we can use as a commodity,, and a more widespread adoption of electric cars.