nominal_value and actual_value

Flows have attributes nominal_value and actual_value. The latter, actual_value, gives information about the temporal profile of the flow. It is internally multiplied by nominal_value.

• Remark: A power timeseries does not necessary attain the maximal possible value or the nominal value in a given time interval. Scaling a timeseries so its maximum is not the same as scaling it to its general nominal value.
• Terminology: Nennleistung is not necessarily the same as maximal power (https://www.energie-lexikon.info/leistung.html, section “Nennleistung”). The docu does not draw this distinction . This means that a non-normalized power timeseries may contain values above the Nennleistung. E.g., PV can in some conditions produce more than its peak power which is measured under standard test conditions.

How to handle this?

My opinion: As flows are pretty flexible and can be used in many contexts, I suggest to avoid restricting its use just to meet the terminology of special cases. However, I would clearly state that nominal_value and actual_value are internally multiplied.

In this case, actual_value should be allowed to be >1. Without investment, this is already possible. In investment mode, it will lead to zero flow.

It seems to be caused by this constraint in blocks.py:

    def _max_investflow_rule(block, i, o, t):
        """Rule definition of constraint setting an upper bound of flow
        variable in investment case.
        """
        expr = (m.flow[i, o, t] <= (
            (m.flows[i, o].investment.existing + self.invest[i, o]) *
             m.flows[i, o].max[t]))
        return expr
    self.max = Constraint(self.FLOWS, m.TIMESTEPS,
                          rule=_max_investflow_rule)

[jnnr]

I prefer [2] 😃

[uvchik]

Closed by #680