Interim Data Changes in the Short-term Energy Outlook Data Systems Related to Electric Power Sector and Natural Gas Demand Data Revisions
December 1, 2002
Beginning with the December 2002 issue of EIA’s Short-Term Energy Outlook (STEO), electricity generation and related fuel consumption totals will be presented on a basis that is consistent with the definitions and aggregates used in the 2001 edition of EIA’s Annual Energy Review (AER). Particularly affected by these changes are the demand and balancing item totals for natural gas. Table DR1 below provides annual comparisons for selected variables used in the old STEO system between the way the variable was traditionally presented in the STEO and as it would be calculated based on the latest AER-type data. This is provided to indicate the significance of any data changes from marking to the AER2001 totals.
A number of changes in the display format for traditional STEO Tables have also been instituted. In particular, electricity generation categories now break out into the Electric Power sector (electric utilities and independent power producers) and other sectors, including generation from combined heat and power (CHP) or electricity-only plants in the commercial and industrial sectors. Fuel consumption in the industrial sector is displayed so as to indicate the amount of fuel used by CHP and electricity-only generating plants separate from other industrial fuel use for selected fuels, specifically coal and natural gas. Tables DR2 through DR7 illustrate key changes in STEO table formats.
These changes are considered interim revisions because certain details concerning the estimation of monthly patterns for components of electricity supply and related fuel consumption require additional work to generate optimal estimates. In addition, the pending release of EIA’s Natural Gas Annual (January 2003) is expected to improve 2001 estimates of the natural gas demand and supply estimates for 2001 in the context of the new AER data format. Improved estimates of historical monthly values for many of the key electricity and fuel-for-power variables are expected to become available when the new data format is incorporated in EIA’s Monthly Energy Review in the Spring of 2003.