Model-Based Sampling Methodology for the New Form EIA-923 ASA-EIA Fall Meeting October 18, 2007 Joel Douglas “*This is a working document prepared by the Energy Information Administration (EIA) in order to solicit advice and comment on statistical matters from the American Statistical Association Committee on Energy Statistics. This topic will be discussed at EIA's fall 2007 meeting with the Committee to be held October 18 and 19, 2007.” “*This is a working document prepared by the Energy Information Administration (EIA) in order to solicit advice and comment on statistical matters from the American Statistical Association Committee on Energy Statistics. This topic will be discussed at EIA's fall 2007 meeting with the Committee to be held October 18 and 19, 2007.”

Form EIA-923 Introduction “Power Plant Operations Report” Form EIA-923 Introduction “Power Plant Operations Report” Merges Data Elements From 5 Current Forms: Merges Data Elements From 5 Current Forms: EIA-906 “Power Plant Report”EIA-906 “Power Plant Report” EIA-920 “Combined Heat and Power Plant Report”EIA-920 “Combined Heat and Power Plant Report” EIA-423 “Monthly Cost and Quality of Fuels for Electric Plants Report”EIA-423 “Monthly Cost and Quality of Fuels for Electric Plants Report” FERC-423 “Monthly Report of Cost and Quality of Fuels for Electric Plants”FERC-423 “Monthly Report of Cost and Quality of Fuels for Electric Plants” EIA-767 “Steam-Electric Plant Operation and Design Report ”EIA-767 “Steam-Electric Plant Operation and Design Report ”

Form EIA-923 Data Summary Form EIA-923 Data Summary Data of Interest for Monthly Sampling: Data of Interest for Monthly Sampling: EIA Generation, Consumption, and StocksEIA Generation, Consumption, and Stocks EIA Generation, Consumption, and StocksEIA Generation, Consumption, and Stocks EIA Fuel Receipts, Fuel Cost, and Fuel QualityEIA Fuel Receipts, Fuel Cost, and Fuel Quality FERC Fuel Receipts, Fuel Cost, and Fuel QualityFERC Fuel Receipts, Fuel Cost, and Fuel Quality

Form EIA-923 Data Summary Form EIA-923 Data Summary GenerationConsumptionStocks Receipts (Cost & Quality) Electricity Only Facilities (EIA- 906) Unregulated Facilities (EIA- 423) Combined Heat and Power Plants (EIA- 920) Regulated Facilities (FERC- 423)

Sample Selection Goals Sample Selection Goals Sample Size Reduction Sample Size Reduction Commercial and Industrial SectorsCommercial and Industrial Sectors Smaller facilitiesSmaller facilities Reduce Both Respondent and EIA Burden Reduce Both Respondent and EIA Burden Respondent Burden = Respondent CountRespondent Burden = Respondent Count EIA Burden = Facility CountEIA Burden = Facility Count

Reasons for Using Model-Based Cutoff Sampling Instead of Design-Based Sampling For Electric Power Data Difficulty in collecting smallest respondents require that they be left out of the sample. Smallest respondents tend to have disproportionately large nonsampling error Due to the highly skewed nature of electric power data, the smallest respondents do not affect aggregated totals very much. Since very good auxiliary / regressor data are available, regression models are useful (i.e. Low variance and model failure is limited to data that should be modeled anyway) Better use of resources to raise accuracy and lower respondent and Government burden. EIA has produced good results for nearly two decades utilizing model based cutoff sampling

Sample Selection Outline Sample Selection Outline Sampling groups mirror the generation groups in the Electric Power Monthly publication. Sampling groups mirror the generation groups in the Electric Power Monthly publication. These groups represent the intersection of the following three levels: These groups represent the intersection of the following three levels: Facility TypeFacility Type Fuel TypeFuel Type Geographic RegionGeographic Region

Sample Selection Outline Cont. Facility Types (4) Facility Types (4) Regulated (REG)Regulated (REG) Independent Power Producers (IPP)Independent Power Producers (IPP) Commercial (COM)Commercial (COM) Industrial (IND)Industrial (IND)

Sample Selection Outline Cont. Fuel Types (14) Fuel Types (14) - Coal - Geothermal - Hydroelectric - Natural Gas - Nuclear - Other Gas - Other Sources - Petroleum - Petroleum Coke - Pumped Storage - Solar - Waste - Wind - Wood

Sample Selection Outline Cont. Geographic Regions (10 Modified Census Divisions) Geographic Regions (10 Modified Census Divisions) - Middle Atlantic - South Atlantic - East Central - West Central - East North Central - New England - West North Central - Mountain - Pacific Contiguous - Pacific Non-Contiguous

Sample Selection Outline Cont.

Sampling Methodology Summary Five Steps Five Steps Step #1 – Capacity CutoffsStep #1 – Capacity Cutoffs Step #2 – Reported Value CoverageStep #2 – Reported Value Coverage Step #3 – Estimation Group CountsStep #3 – Estimation Group Counts Step #4 – Acceptable RSEsStep #4 – Acceptable RSEs Step #5 – Additional FacilitiesStep #5 – Additional Facilities

Sample Selection Procedure Step #1 Cutoff sampling methodology based on operating nameplate capacity Cutoff sampling methodology based on operating nameplate capacity Ensure adequate capacity coverage by sector, fuel type, and region Ensure adequate capacity coverage by sector, fuel type, and region Regulated – 70%Regulated – 70% Independent Power Producer – 70%Independent Power Producer – 70% Commercial – 50%Commercial – 50% Industrial – 50%Industrial – 50%

Sample Selection Procedure Step #2 Add additional facilities that rank within a preset percentage of actual generation, consumption and stocks and are not included in the capacity cutoff sample. Add additional facilities that rank within a preset percentage of actual generation, consumption and stocks and are not included in the capacity cutoff sample. Regulated – 50%Regulated – 50% Independent Power Producer – 50%Independent Power Producer – 50% Commercial – 25%Commercial – 25% Industrial – 25%Industrial – 25%

Sample Selection Procedure Step #3 Ensure adequate estimation group coverage Ensure adequate estimation group coverage Estimation groups must have a minimum of 10 monthly observed valuesEstimation groups must have a minimum of 10 monthly observed values Grouping parameters are similar to the sampling parameters, with a few notable exceptions.Grouping parameters are similar to the sampling parameters, with a few notable exceptions.

Sample Selection Procedure Step #4 Ensure fuel group Relative Standard Errors (RSEs) are within reasonable range at the US regional level. Ensure fuel group Relative Standard Errors (RSEs) are within reasonable range at the US regional level. Regulated – RSE < 5%Regulated – RSE < 5% Independent Power Producer – RSE < 5%Independent Power Producer – RSE < 5% Commercial – RSE < 10%Commercial – RSE < 10% Industrial – RSE < 10%Industrial – RSE < 10%

Sample Selection Procedure Step #5 Add additional facilities which do not add much to respondent or EIA burden Add additional facilities which do not add much to respondent or EIA burden Mainly large coal and natural gas facilities that are in the current EIA-906 / EIA-920 monthly sample. Mainly large coal and natural gas facilities that are in the current EIA-906 / EIA-920 monthly sample. Approximately 200 additional respondents added Approximately 200 additional respondents added

Final Results - Counts

Final Results - Percent

Final Results – Generation Volume

Further Information The sampling methodology is also described in the OMB Federal Register Notice associated with the Electricity 2008 Project. The sampling methodology is also described in the OMB Federal Register Notice associated with the Electricity 2008 Project. city/page/fednotice/elect_2008.html city/page/fednotice/elect_2008.html city/page/fednotice/elect_2008.html city/page/fednotice/elect_2008.html