24-09-2025, 02:29 PM
Thanks for the fast reply, @Antti-L!
In the optimal solution, the process is only used for shifting tiny amounts of energy around. So the "wasted" energy from this idle charging and discharging is negligible in the context of the entire model. Still, I found it weird.
Particularly, because the simultaneous charge/discharge goes on in every timeslice across the entire modelling horizon. There is not a single timeslice where either VAR_FIn or VAR_FOut is numerically zero.
It is not serving any demand directly. It stores district heat serving the end-use sectors. I was also thinking whether some constraints push the model to use this storage for demand shedding. But the amounts are tiny and there are other processes with zero associated costs that are better suited to shed energy, I'd wager.
In the optimal solution, the process is only used for shifting tiny amounts of energy around. So the "wasted" energy from this idle charging and discharging is negligible in the context of the entire model. Still, I found it weird.
Particularly, because the simultaneous charge/discharge goes on in every timeslice across the entire modelling horizon. There is not a single timeslice where either VAR_FIn or VAR_FOut is numerically zero.
Quote:But of course, due to the storage losses such would not happen unless either 1) the electricity price in those timeslices is zero or even negative, or 2) you have added some constraints that can be best satisfied by using the device in this way, or 3) the storage is directly serving a demand that has a load profile covering all timeslices (such as cell phone batteries, for example).
It is not serving any demand directly. It stores district heat serving the end-use sectors. I was also thinking whether some constraints push the model to use this storage for demand shedding. But the amounts are tiny and there are other processes with zero associated costs that are better suited to shed energy, I'd wager.