The displacement or deferral of substation equipment is a key benefit associated with several technologies that are being developed with the support of the US Department of Energy`s Office of Utility Technologies. This could occur, for example, as a result of installing a distributed generating resource within an electricity distribution system. The objective of this study was to develop a model for preparing preliminary estimates of substation capital costs based on rudimentary conceptual design information. The model is intended to be used by energy systems analysts who need ``ballpark`` substation cost estimates to help establish the value of advanced utility technologies that result in the deferral or displacement of substation equipment. This cost-estimating model requires only minimal inputs. More detailed cost-estimating approaches are recommended when more detailed design information is available. The model was developed by collecting and evaluating approximately 20 sets of substation design and cost data from about 10 US sources, including federal power marketing agencies and private and public electric utilities. The model is principally based on data provided by one of these sources. Estimates prepared with the model were compared with estimated and actual costs for the data sets received from the other utilities. In general, good agreement (for conceptual level estimating) was found between estimates prepared with the cost-estimating model and those prepared by the individual utilities. Thus, the model was judged to be adequate for making preliminary estimates of typical substation costs for US utilities.