Topic: Issue of energy balanceSubscribe | Previous | Next
Yun Shu 8/18/2023
Hello Dear
My energy balance data shows a discrepancy of 519.8 in heat, as shown below. Could you please explain the reason? My understanding is that the sum of primary energy supply and total energy conversion in the diagram should be equal the final energy demand. However, the import quantity in the primary energy supply appears unusually high (~1469.4).
Thank you
Yun Shu
Charlie Heaps 8/21/2023
One possible reason: if heat is produced as a coproduct from a process that is being dispatched to meet the demand for electricity, then you may be producing more heat than you need. In these cases the excess or wasted hear will show up as a negative unmet requirement.
Yun Shu 8/22/2023
Hi Charlie, many thanks for your kindly reply.
From the banlance chart we can see that the co-producted heat from CHP is 914.8, which is less than the heat demand of 1862.7. Thus, my understanding is that the heat from imports should be 1862.7-914.8=947.9, rather than the currently displayed 1469.4. I am not sure if my understanding is correct? Thank you.
Charlie Heaps 8/23/2023
1 Like Oh yes - I see what you mean, but it's also got a lot of heat "imports" which probably is not realistic! Those imports are causing the over production of heat and hence the negative "unmet requirements" (i.e. OVERproduction).
I'd suggest investigating why its importing that heat. Suggest looking at the "outputs" branches under each Transformation module to see if there is a target set for heat imports. Failing that, I'm wondering if the "Unmet Requirements" variable under the Resource branches is misbehaving. Perhaps the rule for this variable is set to "MeetWithImports" and that is causing extra imports. It should not be doing that, but if it is, you could try setting the rule for Heat to "RequirementsUnmet" and see if that changes the result.
Please let me know what you find out. If there is a bug I will try to get it fixed for the next release.
Charlie
Yun Shu 8/25/2023
Hi Charlie, many thanks for your suggestions.
First, i opened the target set for each 'heat imports' under the Transformation branches and verified that their settings were set to 0. Then, i set the 'Unmet Requirements' for Heat under the Resources branches to 'RequirementsUnmet', and upon checking the EnergyBalance, i noticed that the 'Unmet Requirements' changed fro the original 519.8 to 950 (which is exactly the result of 1863-913) as shown in fig below. (actually all other energy sources under the Resources branches are set to 'MeetWithImports' by default)
Yun Shu
Charlie Heaps 8/25/2023
Thanks - that does look like there's a bug then in how LEAP is handling unmet requirements. I will try to get this fixed in an upcoming release.
Best,
Charlie
Yun Shu 8/28/2023