Pacific Northwest heat wave sparks record-high electricity demand

Published on August 25, 2017 by Kevin Randolph

The multiple record-breaking heat waves that struck the Pacific Northwest this summer led, in turn, to
record-breaking electricity demand in the region, according to the U.S. Energy Information Administration (EIA).

The highest temperatures occurred on Aug. 3 when Portland reached 105 degrees and Seattle reached 94 degrees, which are 23 degrees and 17 degrees higher than the respective 30-year average highs for those cities.

Bonneville Power Administration (BPA), a federal power marketing administration that provides
hydropower to other balancing authorities in the area, broke its summer peak demand record every day between Aug. 1 and 3. Demand reached the highest level on Aug. 2, when demand hit 8226 MW.

Portland General Electric (PGE), which serves approximately 45 percent of Oregon’s population including the Portland area, experienced a new peak demand record of 3967 MW on Aug. 2. This is only approximately 100 MW lower than the company’s all-time peak demand record of 4073 MW in December 1998.

Seattle City Light (SCL) and Puget Sound Energy, Inc. (PSEI), which serve most of Seattle and the surrounding areas, saw higher demand than during the previous two summers but did not break their summer peak records. Their records were set in July 2009 when temperatures in the region reached 103 to 104 degrees Fahrenheit.

The Pacific Northwest differs from most areas of the country in that many of its electric systems peak in winter rather than summer due to mild summer temperatures. Additionally, a relatively small percentage of homes in the area have air conditioning, which further reduces demand.