Linear Commitment Column
Column Type = Integer
This optional column is used to determine the commitment method for individual resources. This setting offers options to change variables from binary/integer to linear in the optimization solving the commitment and dispatch each day. These variables represent whether or not a unit is online or started in a given hour. In general, the fewer binary variables that exist in the optimization the faster the study will run, so simplifying some or all of the variables as linear will generally improve run time at the cost of less precision.
For resources whose commitment is modeled with linear variables, a unit can be partially online, meaning it can run below the minimum capacity. Partial starts, incurring only part of the start up costs, are also allowed. The effect on run time of using the linear variables may vary significantly from case to case, as will the degree of changes to results.
NOTE: This column is only used with Commitment_Optimization.
The options for this parameter are:
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NULL/blank: defaults to the global setting in the commitment optimization form of Simulation Options.
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0 (None): Does not alter the formulation; binary commitment decisions are used
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1 (All Periods): Uses linear commitment for all periods in the solve
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2 (Lookahead Periods): Uses binary commitment in the first day and linear in the forecast days modeled in the solve (this is only applicable when Dispatch Days in Solve > 1)
There are three places that the linear commitment can be specified:
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at the resource,
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for a whole zone,
Aurora will process the inputs in that order: for a given resource it will use the resource input if specified; otherwise it will use the zone input if specified for the zone containing that resource; otherwise it will use the global value. The global value will also depend on the Start Date entered; before the Start Date the global value will also be None.
NOTE: When linear commitment is active for a resource, it may dispatch below its Minimum Capacity and the Percent_Committed may be a value between 0 and 100.
NOTE: Inputs can be specified for any time period (annual, monthly, weekly, hourly or sub-hourly). For information on how to specify a time series for a variable, see Entering a Time Series.
Linear Commitment Column