Some day gas and crude oil will be a thing of the past. With innovations here and there. In your own opinion what will replace gas and crude oil in the international market.
Solar and other means of generating electricity may replace crude oil and gas but this will take a long time. It may not even happen in our generations. With what I see that is happening now, crude oil and gas can not yet be replaced, it will take a long time before it can happen.
Though some parts of the world are already shifting to renewable sources of energy, we can't discard the fact that we are still heavily relying from gas and crude oil. As the sources are getting exhausted, humans are looking for alternative sustainable energies that can supplement the requirements of the people.