PV plants can lower or raise their active feed-in power. The amount of power reduction is AvlDnW, the amount of power raise is AvlUpW. In this concept, the only flexibility evaluated is the reduction of active feed-in power of PV plants, so AvlUpW=0.. In all graphics, AvlDnW is visualized as a negative value. If implemented, AvlUpW would be represented by positive values.

All visualizations in this concept have been designed to help the user estimate prices in a pay-as-clear scenario: The plant with the highest cost required to fulfill the flexibility request determines the flexibility price for all plants.

To calculate how the power production of PV plants can be adjusted, one needs three parameters: The maximum possible AC power , the current AC power  and the minimum AC power . Using these three parameters, one can calculate the possible power increase  and the possible power reduction  

In this concept, it is assumed that P=Pmax and Pmin=0, so AvlUpW=0 and AvlDnW=Pmax.

To calculate Pmax, a PV simulation is needed. The metadata for each plant is provided by the Marktstammdatenregister, the meteorological data is measured by a weather station.

For the flexibility cost estimation, the cost to adjust the output power of the plant RampCost is required. In Germany, the Erneuerbare Energien Gesetz (EEG) guarantees plants with PDC < 100kW a compensation that is fixed for 20 years and a minimum compensation for plants with PDC ≥ 100kW . The value of the compensation depends on the size of the plant and the date of the first operation. In contrast to the EEG before 2014, the threshold values of power for each category are assumed to be at 10 kW, 30 kW, 100 kW and 1000 kW. All plants that went into operation before the year 2000 are treated like plants from 2000.