Water spill when the water storage is empty

[e-zaline]

I have an hydro power plant (storage node + unit) which is having downward slack (i.e. spills water) when my storage is empty, instead of storing it.
It may be something wrong with the downward slack penalty.

[jkiviluo]

The issue was that the default storage binding method forces start and end values of storage to be the same. The hydro unit also had a higher average inflow than its generation capacity - meaning that there was a surplus of hydro energy that had to be dumped somewhere. The only choice was the downward slack despite the high penalty value.