See Also
Output Cost Model
Cost Model
Simulator can model generators as not having a cost model, or having either a cubic cost model or a piecewise linear model. The cost model type you choose determines the content of the remainder of this dialog
Unit Fuel Cost
The cost of fuel in $/MBtu. This value can be specified only when you have chosen to use a cubic cost model.
Variable O&M
The Operations and Maintenance costs. Only used for cubic cost models.
Fixed Costs (costs at zero MW Output)
The fixed costs associated with operating the unit. These costs are independent of the generator's MW output level and is added to the cost prescribed by the cubic or piecewise linear model to obtain the total cost of operating the generator in $/MWHr. The total fixed cost is the addition of the fuel cost independent value and the fuel cost dependent value multiplied by unit fuel cost.
Cubic Cost Coefficients A, B, C, D
For cubic cost models of the form C(Pgi) = (d*Pgi^3 + c*Pgi^2 + b*Pgi ) * (fuel cost) + fixed costs (as described above), specify the cost curve's coefficients. The A coefficient is historically the fuel cost dependent fixed cost value, which is combined separately now with the fuel cost independent value. These coefficients can be specified only when you have chosen to use a cubic cost model.
Piecewise Linear Table
If you have chosen to use a piecewise linear cost model, a table appears that allows you to specify pairs of MW output levels and corresponding generator operating costs. To insert a new point on the cost curve, right-click on the table and choose Insert New Point from the resulting local menu. To delete an existing point from the cost curve, right-click on the table and choose Delete Point from the resulting local menu. To edit an existing point in the table, simply enter your changes to the appropriate cells.
Convert Cubic Cost to Linear
Use this option to create a piecewise linear cost function from the cubic cost function specified by the coefficients A, B, C, and D and the fuel cost. Specify the number of break points, and hence the number of segments, in the Number of Break Points field. Click the Convert to Linear Cost button to create the piecewise linear function that approximates the cubic cost function. This action switches Cost Model option to Piecewise Linear and displays the Piecewise Linear Table that identifies the piecewise linear curve’s breakpoints.
Bid Scale / Shift
Cost Shift, Cost Multiplier
The cost shift and cost multiplier allow you to easily apply a shift to the cost function for the purpose of assessing how variations in bids impact profit. The cost function is affected based on the following equation:
(Original Cost Function + Cost Shift) * Cost Multiplier
Marginal Cost (run mode only)
Shows the marginal cost of producing real power at the generator at its current output level, dCi(Pgi)/dPgi.
This is the cost of production for this generator following an economic dispatch or optimal power flow solution, including the scaling from the cost shift and cost multiplier fields.
Unscaled Cost (run mode only)
The cost of production of the generator, ignoring the cost multiplier and cost shift. This cost is the result of the original cost function by itself.
OPF Reserve Bids
This tab is only available with the OPF Reserves add-on. Detailed information about this tab can be found in the Generator and Load OPF Reserves Bids topic.