(This is one of the ways Railcraft can attract users)
Coal gas is something like natural gas. It was used to light things in history. It can also be a component of ChemLab. Comments are welcome!

First, the coal gas will be produced in coke oven. It then can be used as fluid fuel, or as some equivalent of steam (another power system)

Definitely not an equivalent of steam. It doesn't have the pressure capable of handling that.

Guys i really liking this idea! i hope be added because look good!

It's not even close to steam @liach. The closest equivalent is raw coal.

I mean it is a type of power unit, just like how steam is considered as eu/rf/charge

Maybe as an internal unit, but I can't see this working anywhere except as a side-by-side multiblock for passive charge. I just don't think it has the potential. Coal coke, and even charcoal, are treated as products and not always produced to create power. They're consumed, yes, but trying to build a system around the production of something leads to logistical nightmares

it's a fluid for fuel and chemlab.

If this is for the chemlab, then let's wait on the implementation until we have actual uses. We have enough fuel sources as-is being quite honest.

Rejected per private discussion.

SynGas was always planned.... Coke + Steam in the ChemLab.