set linear_startup
Toggle the building of linear startup and shutdown costs for generators and pumps on or off when MIP is not active. Default option “/not_set” uses the linear_startup_flag on each plant to decide if startup and shutdown costs should be used
| Options | /on, /off, /not_set |
| Value | |
| License | SHOP_OPEN |
| Release version | 13.0.0.a |
Using linear start-stop costs¶
Using linear instead of integer variables to add pump and generator start-stop costs can be done with the command:
set linear_startup /<option>| Comment | |
|---|---|
| on | Turn on linear start-stop costs |
| off | Turn off linear start-stop costs |
If command not set: Linear start-stop costs will not be used.
Linear start-stop costs allows a unit to have a fractional start or stop, but may reduce solution time of big problems drastically. The following table shows the outcome of combining the commands set universal_mip and set linear_startup. In short, if an hour is flagged as a MIP-hour, integer start-stop costs will be built. If the hour is not flagged as MIP, linear start-stop costs will be used if the command set linear_startup /on is used. Otherwise, no start-stop costs are built, and SHOP sees no cost of turning the unit on or off.
The table below shows what kind of start- stop costs will be used in SHOP if the commands “set linear_startup” and “set universal_mip” are combined:
| set universal_mip /on | set universal_mip /off | set universal_mip /not_set | |
|---|---|---|---|
| set linear_startup /on | Integer start- stop costs used in all hours | Linear start- stop costs used in all hours | Integer start- stop costs used if mip_flag is 1, linear otherwise |
| set linear_startup /off | Integer start- stop costs used in all hours | No start- stop costs used in any hour | Integer start- stop costs used if mip_flag is 1, no start-up costs otherwise |