For 33 years, electricity consumers on the West Coast have benefited from a unique arrangement that allows large amounts of power to be transmitted between the Pacific Northwest and the Desert Southwest. The high-voltage transmission lines that make this power-sharing possible collectively are called the Pacific Intertie.
The Intertie includes three alternating current (AC) lines and one direct current (DC) line. Together, they comprise the largest single electricity transmission program in the United States.
California enjoys the greatest benefit from the Intertie. In the last 15 years, for example, the Northwest has sent more electricity to the Southwest -- mostly to California -- every year than it has received. Power generated in the Northwest has saved Southwest utilities more than 2.8 trillion cubic feet of natural gas that would have been burned in power plants.
Because large amounts of Northwest power can be transmitted reliably to the Southwest, less power has been generated at fossil-fuel power plants -- an important benefit in a part of the country with chronic air pollution problems. Conversely, because the Northwest has been able to import power from California, particularly overnight when demand is low, water can be reserved in reservoirs that otherwise would be used to make electricity -- an important benefit in a part of the country where hydropower operations affect threatened and endangered species of fish. As well, money that southwestern utilities pay for power from the Bonneville Power Administration helps finance fish and wildlife restoration projects in the Columbia River Basin.
Recently, Bonneville announced it will spend $35 million to modernize its portion of the DC line and related facilities. In combination with modernization efforts undertaken by the California partners, the DC line will maintain its 3,100-megawatt capacity far into the future. The equipment replacements are expected to be complete in November 2003.
