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ORNL Develops the Oak Ridge Competitive Electric Dispatch (ORCED) Model for Simulating the Operations and Costs of Bulk Electric Power Markets

Introduction

ORCED is a spreadsheet program for analyzing the electricity supply system for a given region or utility system based on power generating plant information and the region's hourly electric load demands. ORCED uses the plant dispatch information and fuel costs and region's power demands to calculate air emissions, electricity costs and prices, and other operational factors of a regional electricity market. Power plant and demand data are provided on this site for the ten reliability regions of the North American Electric Reliability Council or NERC from 1997. Also, various versions of the program, program documentation, research reports that used the model and presentations are available on this web site for download. Help is available from the author.

Summary

Dramatic changes in the structure and operation of U.S. bulk electric power markets require new analytical tools. As a result, Oak Ridge National Laboratory developed the ORCED model to analyze a variety of public-policy issues related to the many changes underway in the U.S. electricity industry.

ORCED models the electrical system for a region by matching the supplies and demands for two seasons of a single year. Supplies are defined by up to 202 plants with extensive definitions of their operations, costs, and emissions. Demands are defined by load duration curves for each season, with gradually increasing demands based on hourly demands. Real-time prices, unserved energy, capacity payments, and other factors can present a complex financial picture for each plant and the system as a whole. Emissions from the various plants can be tracked. Limited optimization can be carried out. User specification of demand elasticities permits ORCED to estimate the effects of changes in electricity price, both overall and hour by hour, on overall electricity use and load shapes.

The ORCED model was developed primarily with support from the U.S. Environmental Protection Agency and Department of Energy. Three basic versions of the model have been developed. The first version, available on this website, dispatches generation (the output available from 51 power plants) to meet loads in a single region. Fifty of the units are characterized in terms of capacity, forced- and planned-outage rates, fuel type, heat rate, variable and fixed operations and maintenance costs, and annual capital costs (based on construction cost, year of completion, capitalization structure, ongoing capital expenditures, and tax rates). The 51st unit is considered energy-limited (e.g., a hydroelectric unit). The other basic version divides the plants between two regions. They are connected by a single transmission link that is characterized by its capacity, costs, and losses. The model uses separate load-duration curves to represent the time-varying electricity consumption in each region.

The third version, with an example modeling the Oklahoma electric market available on this site, expands the first version by modeling 202 power plant units in a single region.

Although ORCED is not a complex, mainframe-based model, it captures the key features of the U.S. electricity system as it might function with competitive bulk-power markets. In particular, generating units bid their variable costs (the sum of fuel costs plus variable O&M costs) into a market; the market selects the cheapest units to meet electricity demand for each point in time. All generators are paid the same price during each time period, the price bid by the highest-cost unit then operating.

Because of ORCED's user-accessibility, modifications to its calculations can be made relatively easily. Plant operations can be changed or tied to the operations of other plants, new emissions or emission policies can be added, a subset of plants can be tracked separately from the entire group. These are just examples of what the flexibility of ORCED provides.

Model

The ORCED program and data are contained in Microsoft Excel for Windows or MacIntosh (.xls) files. A detailed discussion of ORCED and what it was designed to analyze is provided in the ORNL report entitled "ORCED: A Model to Simulate the Operations and Costs of Bulk-Power Markets. In order to use it, you will need the following files:

1. ORCED program file
   
2. Procedure file for setting up and running ORCED
   
3. Power plant data input file
   
4. Load Duration data input file
   

Click Here to download all of these files for any NERC Region
All four of these files have been bundled into one self-extracting zip file. There are ten sets of these files since an ORCED program file has already been set up for each of the ten NERC regions. The procedures file describes how to change the data parameters within the program file and when to use the two input data files.The ORCED file and procedure file are bundled as one self-extracting zip file. The two data files are also bundled as one self-extracting zip file so there are ten of them since there is a set of files for each of the ten NERC regions.

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