The Western Area Power Administration (Western) has energized the first 20-mile (32-km) segment of an 80-mile (129-km) transmission line upgrade. The project is under way in Arizona and Nevada, with 3M's breakthrough metal matrix, high-capacity aluminum conductor composite reinforced (ACCR).

The heat-sag-resistant conductor can carry more than twice the power of conventional steel-core lines of similar diameter, yet often does not require new or larger towers because of its relatively light weight and low sag.

3M ACCR's strength and durability result from its core, composed of aluminum oxide (alumina) fibers embedded in high-purity aluminum, using a highly specialized and patented process. The constituent materials are chemically compatible with each other and can withstand high temperatures over years of continuous operation without adverse chemical reactions or any appreciable loss in strength.

Western installed a 230-kV 3M ACCR on a line paralleling the Colorado River along Arizona's western border with California. The area served by the line includes fast-growing communities, such as Lake Havasu City and Bullhead City in Arizona; Laughlin, Nevada; and Needles, California.

The conductor was developed with the support of the U.S. Department of Energy, which tested the conductor at its Oak Ridge National Laboratory (ORNL) in Tennessee, and with early contributions by the Defense Advanced Research Projects Agency. The ORNL tests demonstrated the conductor's integrity after exposure to temperatures higher than the rated continuous operating temperature of 210°C (410°F). Further, the ACCR is not adversely affected by environmental conditions and has the durability typically associated with aluminum-based conductors.