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Replacing existing transmission lines, known as conductors, with advanced conductors could enable 764 GW of grid-connected solar power generation by 2035. However, some U.S. utilities are slow to adopt this technology. In a recent webinar, two utilities that have used advanced conductors for years shared their experiences.
While 2,100 GW of solar and storage projects await transmission interconnection in the U.S., re-routing transmission with high-capacity or “advanced” conductors could enable the interconnection of 764 GW of utility-scale solar, researchers have found.
Relay lines can cost-effectively double transmission capacity within existing rights-of-way, allowing projects near relay lines to be more easily interconnected.
Two utilities with experience in rerouting transmission lines shared their experience with advanced conductors and their “lessons learned” in a webinar hosted by Energy Central, a news service for the energy and utilities industry.
The knowledge from these two companies, NV Energy in Nevada and Southern California Edison, could be useful to other companies.
For example, the federally owned Bonneville Power Administration, which primarily serves Washington, Oregon and Idaho, said in January that it had “begun the process” of analyzing and qualifying advanced conductors to increase the capacity of its grid, adding that the process “may take months or years of physical testing and analysis.”
Analysts at Energy Innovation and GridLab have questioned BPA’s approach, which they say is common to many other transmission providers. They suggested that utilities should rely on real-world deployments or trials by other peer organizations. The analysts said BPA’s approach “significantly slows down the integration of many emerging technologies, not just advanced conductors.”
NV Energy has been re-routing lines with advanced conductors since 2009, said Jim Lehan, the companys director of transmission and civil engineering. He said the advanced conductors the company uses have survived a transmission tower blown sideways by high winds, as well as exposure to fire.
The company now has 76 miles of advanced conductors on 20 circuits, and is developing additional projects that will use 56 miles of advanced conductors. Lehan said a type of advanced conductor known as ACCC, made by CTC Global, “has become a standard for us, because it’s so high-capacity.” As the company deals with growing demand, “we’re installing” advanced conductors “at every site we can,” he said.
In California, SCE has installed 385 circuit miles of ACCC conductors since 2016, said Robin Castro, the companys transmission and distribution asset engineering manager, and expects to install 300-400 more circuit miles of the conductors by 2030.
SCE expects to invest up to $75 billion in its grid from 2030 to 2045, Castro said, including re-routing existing lines and building new circuits, to accommodate an expected 80 GW of “new clean generation, including wind and solar” and 30 GW of battery storage.
"SCE has chosen ACCC InfoCore as the standard for the future," he said. This type of ACCC conductor has optical fibres embedded in its core, through which a signal can be sent to check the integrity of the core.
David Bryant, chief technology officer at CTC Global, said in the webinar that “probably 95%” of the re-conduction projects the company has done “have saved the utility money and/or accounted for some anticipated growth.”
He described a new transmission line in Canada where “capacity increases of 65% were achieved with a cost delta of only 1%” of the total project cost by using ACCC conductors instead of an alternative type of conductor.
Bryant also highlighted the benefits of reduced line losses thanks to advanced conductors, which “are not typically considered in the US because those losses are simply passed on to consumers.”
The U.S. Department of Energy, in its call for a national collaboration to deploy technologies that can increase transmission capacity, noted that reconductors have substantial potential to do so. |
