Ames National Laboratory to test new electrical transmission line that could improve grid resiliency

Material scientists from the U.S. Department of Energy’s Ames National Laboratory are moving into the field-testing stage of a new type of high voltage overhead power conductor (cable). The conductor is similar to today’s long distance power transmission lines, but is made of an aluminum-calcium composite previously developed and patented by Ames Lab. The aluminum-calcium conductor is lighter and stronger than those currently in use and has at least 10% lower line losses than existing materials. This conductor could improve the nation’s grid reliability and performance.

The high voltage overhead conductors used today have been the industry standard for more than half a century. The most common type is made of aluminum with a steel core. Using these two dissimilar metals poses a variety of challenges, including how they respond to weather events such as ice, wind, and storms. Many of these challenges can be eliminated by using a conductor made from a uniform material, such as one made from strands of the aluminum-calcium composite.

Iver Anderson, lead researcher for the project, explained that the composite is made of microscopic calcium filaments that act as a lightweight reinforcement for the aluminum. Aluminum is an excellent conductor, but it is too weak to use alone in a conductor strung between power poles. The calcium in this new composite eliminates the need for a heavy steel core.

“While most metal composite experts would not think of using another weak metal to add strength to aluminum,” said Anderson. “But, when calcium is co-deformed with aluminum (like striped toothpaste) they form very thin, long threads of calcium metal that make the aluminum stronger without making it more brittle.”

The composite is made from fine aluminum powder blended with a small amount of calcium powder (less than 10% total). Anderson’s team used their expertise in powder processing to overcome the manufacturing challenges associated with converting highly reactive calcium into the fine powder needed for the composite.

Ames Lab partnered with a complete supply chain of seven U.S. companies to manufacture the first prototype sample conductor. After co-deforming the compacted powders into a bar, the conductor can be processed with the same manufacturing steps that are typically used for conventional overhead transmission conductors.

Recently, Ames Lab has joined in a partnership with Mid-American Energy. The regional power company, based in Des Moines, Iowa, will field test conductor. They will string it between existing transmission towers to determine how well it performs in the real world. They will test variable electrical loads and all the heat, cold, wind, and severe weather that the plains of Iowa can dish out.

“Although the strength, conductivity, and other properties of individual strands of the new composite conductor have been measured in the Lab, measurements on the full conductor form in the natural environment are critical to industry acceptance of this new conductor choice,” said Anderson.

Using this aluminum-calcium power conductor for overhead transmission lines, in place of traditional steel-core conductor, can lead to improved power grid resiliency and efficiency. These new transmission lines can play an important role in supporting the nation’s clean energy goals by moving clean-energy-generated power where it is needed.

This research is supported by the Advanced Materials and Manufacturing Technologies Office (AMMTO), part of the Energy Efficiency and Renewable Energy Office, U.S. Department of Energy. The AMMTO supports a globally competitive U.S. manufacturing sector that accelerates the adoption of innovative materials and manufacturing technologies in support of a clean, decarbonized economy.

Ames National Laboratory is a U.S. Department of Energy Office of Science National Laboratory operated by Iowa State University. Ames Laboratory creates innovative materials, technologies, and energy solutions. We use our expertise, unique capabilities, and interdisciplinary collaborations to solve global problems.

Ames National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, please visit https://energy.gov/science.