What does oil price have to do with relative (opportunity) cost?

Question

What does oil price have to do with relative (opportunity) cost?

Answer 1

The other forms of energy that we could use the money for, other than oil. By using oil, we give up other forms of energy.

Answer 2

As the prices rise that gives us the option to consider other forms of energy that we have before overlooked. Like wind, water and solar energy.

When prices on one product increase it gives lead to others to go out seeking something that is cheaper or other means that have not been given the thought of to explore.

So you see that over the years these forms have been neglected because of oil (opportunity cost of buying oil over alternative energy)