Hi,
I am modelling an electrolysis process where the input commodity is electricity (ELEELC) and output commodity is hydrogen (H2GREEN).
For this process, the capacity (CAP_BND) is 1 GW, which I thought would be the input capacity. That is, this process should consume 1 GW of electricity at max and produce hydrogen according to the efficiency and utilisation factor.. However, the capacity is a representation of the output commodity and the process is producing hydrogen equivalent to 1 GW and to do so, it is consuming electricity more than 1 GW.
Is there a way to change this? I want the capacity to represent the output commodity.
16-06-2025, 05:26 PM (This post was last modified: 17-06-2025, 02:52 AM by Antti-L.
Edit Reason: why output
)
Yes, just define the PCG to be the input (in FI_Process), and then the activity and capacity will be defined by the input flow. But then the efficiency would have to be defined in a different way, for example by using an Output parameter.
EFF is always an efficiency measured from the shadow group to the activity, and therefore, if the activity would be the input flow, EFF=0.6 would mean that you will have 0.6 units of input per one unit of the output in the shadow group. That's why I suggested above that Output might correspond to what the user wishes.
(16-06-2025, 05:26 PM)Antti-L Wrote: Yes, just define the PCG to be the input (in FI_Process), and then the activity and capacity will be defined by the input flow. But then the efficiency would have to be defined in a different way, for example by using an Output parameter.
EFF is always an efficiency measured from the shadow group to the activity, and therefore, if the activity would be the input flow, EFF=0.6 would mean that you will have 0.6 units of input per one unit of the output in the shadow group. That's why I suggested above that Output might correspond to what the user wishes.
Thanks Antti, that solves the problem! Although I had to change the efficiency like you said. Now it is more like a ratio of input/output, which means it is more than 100%. However this approach works for my case.
I had another question, when I specify the PCG to be the input in FI_Process, I don't see the levelised cost (LEVCOST) for those processes. Why is that?
18-06-2025, 03:47 PM (This post was last modified: 18-06-2025, 03:50 PM by Antti-L.)
Yes, as mentioned in the documentation, the levelized cost is calculated per unit of main output, and
"The outputs of the main products are taken from the flow levels of the commodities in the primary group (PG) of the process. An exception is CHP processes, for which the electricity output is considered the sole main output, and heat is considered as a by-product."
Therefore, if the PCG is on the input side, currently no levelized costs are calculated. The problem with that case is of course related to possible multiple outputs of various types, which would make such cases not well defined. I guess for processes with a single output (although not PCG) the calculation could also well be supported, but as stated, for now it is not.
18-06-2025, 03:55 PM (This post was last modified: 19-06-2025, 01:17 PM by Antti-L.)
As an easy workaround you could define the process with the output hydrogen as the PCG and by defining EFF=1 and PRC_ACTFLO(hydrogen)=(efficiency from electricity to hydrogen). By doing so, the activity and capacity would effectively be defined by the power input. The drawback here is that one cannot differentiate PRC_ACTFLO by timeslice.
Another workaround is to define PRC_PKAF for the process. When doing so, any input PCG commodities are assumed directly attributable to the main product(s). However, the levelized cost is in that case calculated per unit of the input flow.
