As 2100 GW of solar and storage projects await transmission interconnection in the U.S., reconductoring transmission with high-capacity or “advanced” conductors could enable interconnection of 764 GW of utility-scale solar, researchers have found.
Reconductored lines can cost-effectively double transmission capacity within existing rights-of-way, enabling projects near reconductored lines to more easily interconnect.
Two utilities with experience in reconductoring transmission lines shared their experience with advanced conductors and their “lessons learned” in a webinar hosted by Energy Central, a news service for the power and utilities industry.
Insights from the two utilities, NV Energy in Nevada and Southern California Edison, could prove helpful to other utilities.
For example, the federally-owned utility Bonneville Power Administration, serving primarily Washington, Oregon and Idaho, said in January it has “begun the process” to analyze and qualify advanced conductors to increase the capacity of its grid, adding that the process “can take months or years of physical testing and analyses.”
Analysts at Energy Innovation and GridLab have challenged BPA’s approach, which they said is common across many other transmission providers. They suggested that utilities should rely on real-world deployments or other peer organizations’ testing. The analysts said BPA’s approach “considerably slows integration of many emerging technologies, not just advanced conductors.”
NV Energy has been reconductoring lines with advanced conductors since 2009, said Jim Lehan, the company’s manager of transmission and civil engineering. He said the advanced conductors the company uses have survived a transmission tower blown sideways by high wind, as well as fire exposure.
The utility now has 76 miles of advanced conductors across 20 circuits, and is developing additional projects that will use 56 miles of advanced conductors. Lehan said that 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 utility faces demand growth “we are putting up” advanced conductors “everywhere we can,” he said.
In California, SCE has installed 385 circuit-miles of ACCC conductors since 2016, said Robin Castro, the utility’s 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 reconductoring existing lines and building new circuits, to integrate a forecasted 80 GW of “new clean generation, which includes wind and solar” and 30 GW of battery storage.
SCE has “moved to ACCC InfoCore as our standard moving forward,” he said. That type of ACCC conductor has optical fibers embedded in the conductor’s core, through which a signal may be sent to check core integrity.
David Bryant, CTC Global’s director of technology, said on the webinar that “probably 95%” of the reconductoring projects the firm has done “have generally saved the utility money and/or accommodated a little bit of projected growth.”
He described a new transmission line in Canada that was “able to get a 65% increase in capacity at a cost delta of only about 1%” of the overall project cost by using ACCC conductors instead of an alternative type of conductor.
Bryant also noted the benefits of reduced line losses from advanced conductors, which he said “usually are not taken into consideration in the U.S., because those losses are just passed along to consumers.”
The U.S. Department of Energy, in its call for a national collaboration to deploy technologies that can increase transmission capacity, flagged reconductoring as having a substantial potential to do so.
A recording of the webinar is available online.
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