Facility Initial Production

Units:	-
Mode:	Input Only
Multi-band:	False
Default Value:	0
Validation Rule:	≥0
Key Property:	No
Description:	Production at time zero

Facility Initial Production sets the initial (t=0) production state of the facility i.e. the total production across all units. It is used to initialize constraints such as Max Ramp Up, Max Ramp Down, Min Up Time, Min Down Time, Max Up Time, and Max Down Time. This property is combined with Initial Units Generating and Initial Hours Up or Initial Hours Down when enforcing minimum/maximum up and down time constraints. If you omit Initial Units Operating then it is assumed that, if the initial production is non-zero, all available units are running, otherwise if Initial Production is zero then all units are off at t=0.

If Initial Production is not defined then the initial production is freely optimized i.e. a value is determined by the optimization that minimizes the impact of the initial conditions on the overall system cost.

Table 1: Initial Production Example

Property	Value	Units
Units	1	-
Max Operating Level	500	-
Min Operating Factor	24	%
Max Ramp Up	120	-
Max Ramp Down	120	-
Initial Production	350	-
Initial Units Generating	1	-
Initial Hours Up	6	h
Initial Hours Down	0	h
Min Up Time	18	h
Min Down Time	12	h

In the example in Table 1 the production at t=0 is one unit operating at 500. Because the maximum ramp is 120 the unit can reach a maximum of 470 (350 + 120) or minimum of 230 (350 - 120) in the first hour. Additionally, the unit has been up for six hours and must continue operating for a further 12 to meet the minimum up time.