Oct. 29, 2002 — The Energy Information Administration (EIA) has changed how it estimates and presents data on the fuels used to produce electricity.
The purpose of these changes is to improve data quality, ensure that data are reported consistently throughout EIA publications, and provide users with a better understanding of how fuels are consumed – whether in plants that only produce electricity (electricity-only plants) or in plants that produce electricity and some form of thermal energy (combined-heat-and- power plants).
Revisions to historical fuel consumption data (particularly for natural gas) and changes in the categorization and reporting of data, begin with today’s release of EIA’s Annual Energy Review 2001 (see: http://www.eia.doe.gov/emeu/aer/contents.html), and continue with the upcoming editions of the “Natural Gas Annual”, “Electric Power Annual”, “Electric Power Monthly”, “Monthly Energy Review”, “Short-Term Energy Outlook”, “Natural Gas Monthly”, and other EIA reports.
These revisions have been motivated by the changing structure of the electricity industry and users’ questions regarding the consumption of fuels used to produce electricity. In recent years the ownership structure of the electricity industry has become increasingly complex, with many utilities divesting their generating plants or selling them to other utilities or independent power producers.
Separating power plants and their associated generation and fuel use into utility or nonutility (e.g., independent power producer) categories, as has been done in the past, is no longer straightforward and may not be meaningful in many circumstances.
To reflect the changing industry structure, EIA is now organizing electric power generation and fuel use data into two new categories – electricity-only plants and combined-heat-and-power (CHP) plants. These categories separate power plants by function – i.e., power generation only or power generation plus thermal (e.g., hot water or steam) – rather than ownership class.
The generation and fuel use for CHP plants are now shown in the end-use category they report as their major line of business (using the North American Industrial Classification System). For example, a CHP plant that reports that it is part of a hospital is shown as a CHP plant under the commercial sector. Similarly, a CHP plant that reports that it is part of a paper mill is shown under the industrial sector.
Those CHP plants that report that their primary business is selling power to others are reported as CHP plants in the electric power sector. Furthermore, the fuel used at CHP plants will be separated into the amount that is used to produce electricity and the amount that is used to produce thermal energy.
This categorization allows readers to determine how much fuel is used solely to produce electricity.
To ensure accurate reporting of the generation and fuel use for the new categories, EIA also undertook an extensive review of reported data for nonutility power producers for 1989 through 2001. Before this review, some of EIA’s estimates of nonutility fuel consumption were based on information from fuel suppliers rather than data collected directly from power plants.
The nonutility power plant data are now being used. This substitution results in revisions to historical data previously reported. For example, total estimated natural gas consumption in 2000 is being revised from 22.71 trillion cubic feet to 23.46 trillion cubic feet, an adjustment of 3.3 percent.
Conversely, total estimated renewable energy consumption in 2000 is being revised from 6,823 trillion Btu to 6,465 trillion Btu, an adjustment of 5.2 percent. Changes to the consumption of other fuels (distillate, residual oil, and coal) are less than 1 percent each.
A more detailed discussion of the review process and the resulting changes to the reporting of data can be found in “Estimating and Presenting Electric Power Sector Fuel Use in EIA Publications and Analyses” at http://www.eia.doe.gov/emeu/aer/pdf/pages/sec_h.pdf.