The whole Civ series has done a terrible job simulating the importance of energy

[Bechhold]

Brainstorm bring back factories being able to power extra hammers but also allow said power to be shared via diplomacy to other civs.

 

[killmeplease]

combutsion tech could provide a gas station building (consumes oil) allowing to work 2 farms by 1 citizen in a city (mechanization effect i've proposed in other thread).

or the oil resource could be needed for refinery building, which would produce 2-3 gasoline fuel resource units which in turn would be consumed by gas stations and military units.

 

[HeraldtheGreat]

In the future era, there should be antimatter plants that produce +25-50% or something.

 

[steveg700]

For oil, there could be a power plant unlocked at Electricity. It provides bonus production by itself, and extra food with Refrigeration.

The problem with the game is that it's too warlike for strategic resources to be critical to a civilization. We may fight wars over oil, but for the most part, they want to sell it and we want to buy it.

 

[kirbdog]

I think you could represent this by people producing more unhappiness if you don't have a healthy surplus of the energy resources. After all, people always get by, but you might have to placate them with more circuses and wine if you can't support modern tastes in your empire.

For example, when you are in the atomic era, if you have failed to secure 1 surplus oil for every 10 citizens, then you 10% extra unhappiness from citizens, and if you have failed to secure 1 surplus oil for every 20 citizens, then you get 20% extra unhappiness. This could stack with unhappiness from failure to obtain coal by the previous modern era and from failure to obtain horses by the medieval era, to become a very big problem for an empire without energy.