I hope I understood your question correctly. I'll try to answer to the best of my abilities.

To answer your question 1) Yes, you should choose the CHP database that is respective of power only, such as "Electricity, high voltage {PT}| heat and power co-generation, natural gas, conventional power plant, 100MW electrical | APOS, U"

To answer question 2) Let's assume your process consumes 3 GJ/functional unit of power, and that you generate 3+1 GJ of power/functional unit in your CHP unit.

What you should do in SimaPro is insert the 3 GJ in the "Energy inputs to technosphere" section, using the abovementioned ecoinvent database, and the 1 GJ in the "Avoided products" section - only if you assume that the generated power in excess replaces electricity generation in the grid upon which you inject it. If the excess power cannot be valorized by entities outside your system boundaries, you should not assign a credit to it.

The database you should choose to model that 1 GJ of power avoided should be the national (or regional, if available) electricity mix correspondant to the location where your biogas production is. For example, if your plant is in Italy, you should choose the Italian electricity mix as the avoided product.

Hope I was helpful!

Hi gustavo,

Thank you so much for your answer. it helps me a lot

The CHP here is the process of electricity generation made from biogas generated in anaerobic digestion. since it generates excess electricity, so that, every electricity consumed in other process like pretreatment, fermentation etc, I select this CHP process rather than selecting the data from the data base. is it correct right?

How I validate whether my LCA result has been correct or not?

do you have any example on how I perform sensitivity analysis in SimaPro for biorefinery process?

Hi Gustavo and Rendra.

The answer will depend of the borders of your system.

If you consider all the process (pretreatment, hydrolysis, fermentation, separation, biogas production, and CHP (electricity generation) as your system, then:

According this approach, the Inventory won´t reflect a Power Input inside your limits, but it will reflect an output (for instance, 3 GJ/functional unit to cover the electricity demand and 1 GJ/functional unit of surplus electricity). The output will be 1 GJ/functional unit of electricity.

1) If you generate the enough electricity to satisfy all power demand of your process, you don´t need to select "Energy inputs to technosphere", because actually no one electricity is crossing the limits of your system (as an Input), because you are creating this energy inside of the process (3 GJ/functional unit).

2) On the other hand, if you have a surplus of power (after covering all power demand of the process, 3 GJ/functional unit), this surplus can be accounted as "Avoided Product" and will be crossing the borders of the system, for instance towards power grid in Italy (1 GJ/functional unit). So, it will be a credit, as Gustavo said: only if you assume that the generated power in excess replaces electricity generation in the grid upon which you inject it.

Regards!