EIA changes weather assumptions

Petroleum News Alaska Staff

Beginning with the Sept. 7, 1999 release of its “Short-Term Energy Outlook,” the Energy Information Administration is adopting weather premises that reflect a three-decade long warming trend identified by the National Oceanographic and Atmospheric Administration. These new assumptions about expected temperatures result in substantial seasonal shifts in U.S. energy demand projections as well as a net reduction in projections of annual energy demand.

Adopting the warming trend in place of long-term averages for the period October 1999 to September 2000 lowers total annual projected energy consumption by about 0.3 percent. On a seasonal basis, the adoption of the warming trend has its greatest demand impact during the winter quarter (January through March 2000), during which total energy consumption is adjusted downward by about 1 percent. The only seasonal increase in energy demand (less than 0.2 percent), attributable to increased fossil fuel utility requirements to meet increased cooling-related electricity demand, occurs in the summer (July through September 2000).

Expected natural gas demand exhibits the largest relative adjustment (down 0.8 percent) due to the change in weather assumptions. Natural gas constitutes 24 percent of total fuel supply, but accounts for three-quarters of the adjustment to expected energy demand resulting from the change in weather premises.

In past forecasts, EIA had assumed temperatures would follow the averages seen over the period 1961 through 1990. In a study published earlier this year, NOAA observed that average temperatures in the Lower 48 states have risen more than half a degree Fahrenheit since the mid-1960s. NOAA now incorporates that trend in its long-range weather forecasts. The warming trend, according to NOAA, dating to 1965, has resulted in both milder winters (which lower heating-related energy demand), and warmer summers (which raise cooling-related energy demand).