By 1961, US president John F. Kennedy authorized a large public works project, using new high voltage direct current technology from Sweden.

Private California power companies had opposed the project but their technical objections were rebutted by Uno Lamm of ASEA at an IEEE meeting in New York in 1963.

When completed in 1970 the combined AC and DC transmission system was estimated to save consumers in Los Angeles approximately US$600,000 per day by use of cheaper electric power from dams on the Columbia River.

In summer, the north uses little electricity while the south reaches peak demand due to air conditioning usage.

Any time the Intertie demand lessens, the excess is distributed elsewhere on the western power grid (states west of the Great Plains, including Colorado and New Mexico).