I am trying to account process emissions from cement production, namely emissions from the chemical reaction to obtain clinker.

Do I have to account it as an "effect" with a fixed emission factor, directly from the branch?

Thank you!

If you are modeling cement as a subsector under (for example) the Demand\Industry sector in LEAP then you can include both combustion and process emissions under those branches. You can include two separate effect branches for combustion vs process emissions. Both could be made a function of energy use, or you could choose to model process emissions in total or make them a function of the tonnes of cement produced.

Alternatively, you can include cement process emissions under the Non Energy sector branches in LEAP. This approach is more inline with how such emissions are accounted for in the IPCC's GHG inventory accounting methodology, but it has the drawback of being separated from the development of the cement sector that you would model in your demand branches. To overcome this drawback you could use some key assumption branches to ensure you are using common assumptions about the development of the cement sector.

I hope this helps!

Charlie