Patent ID: 7333861

Claim:
A method for dispatching electricity producing assets associated with an electric power producing plant at a plant load range comprising a plurality of specified plant loads, the method comprising: (a) determining a marginal value for each of one or more given cost contributing factors at each of the plurality of specified plant loads using a model for controlling the electric power producing plant, the model relating plant load and one or more given cost contributing factors; (b) determining a variable cost at each of the plurality of specified plant loads by: (i) multiplying the marginal value of each of the one or more given cost contributing factors at each of the plurality of specified plant loads by a respective unit cost of each of the one or more given cost contributing factors, and (ii) if there are a plurality of given cost contributing factors, summing the results of (i) at each of the plurality of specified plant loads; (c) determining a marginal variable cost at each of the plurality of specified plant loads by computing a derivative of the variable cost at each of the plurality of specified plant loads; (d) defining a marginal cost curve for the electric power producing plant at the plant load range using a collection of the marginal variable costs at the plurality of specified plant loads; and (e) dispatching electricity producing assets associated with the electric power producing plant in accordance with the marginal cost curve for the electric power producing plant at the plant load range, wherein said one or more given cost contributing factors include an emissions allowance cost comprising a NO x emission allowance cost or an SO x emission allowance cost.