Though I realize that it doesn't have to apart of my experience, I hope you do realize that most energy systems people use are green energy systems. The only systems that would produce pollution off the top of my head would be the IC2 generator, Several Engines (Stirling, Combustion, Biogas, and Peat specifically) , and Steam Boilers. Solar Panels, Wind Turbines, Water Turbines, Geothermals, and any type of Electric Engine don't produce pollution. Indeed, even the Nuclear Reactor doesn't produce pollution, only steam (which could make for an interesting IC2 addition).
Not very many people use the polluting generators as a stable power supply, excluding the Steam Boiler. But if you're using Lava like a geothermal system, you wouldn't have exhaust, just cobblestone (cooled lava). Also, be aware that machines themselves don't produce pollution like the OP seemed to imply, electricity certainly does not equal pollution. So my point is, you are just discouraging use of already underused power systems.