I would say this is the current state, no? Not sure I understand in which scenario you would want something else than is the case right now.
- demand < supply: part of the bar is filled showing non-used capacity
- demand = supply: bar 100% filled (this happens also when charging or discharging the battery)
- demand > supply: bar is 100% filled, total of the progress bar is demand now instead of supply and overdemand is shown in red to show how much you need to upgrade the reactor.