No Brainer. Please proceed.
One of the biggest obstacles to expanding clean energy in the United States is a lack of power lines. Building new transmission lines can take a decade or more because of permitting delays and local opposition. But there may be a faster, cheaper solution, according to two reports released Tuesday.
Replacing existing power lines with cables made from state-of-the-art materials could roughly double the capacity of the electric grid in many parts of the country, making room for much more wind and solar power.
This technique, known as “advanced reconductoring,” is widely used in other countries. But many U.S. utilities have been slow to embrace it because of their unfamiliarity with the technology as well as regulatory and bureaucratic hurdles, researchers found.
“We were pretty astonished by how big of an increase in capacity you can get by reconductoring,” said Amol Phadke, a senior scientist at the University of California, Berkeley, who contributed to one of the reports released Tuesday. Working with GridLab, a consulting firm, researchers from Berkeley looked at what would happen if advanced reconductoring were broadly adopted.
While some technological solutions may offer greater transmission capacity increases in specific cases, reconductoring with advanced conductors offers the most significant and relatively unexplored opportunity to substantially increase transmission capacity, considering costs, permitting, and implementation speed. The vast majority of transmission lines in the U.S. are short (i.e., <50 miles) and thus most likely limited by the conductor’s thermal capability. In these cases, reconductoring with advanced conductors, combined with marginal substation additions as needed (reactive power compensation, transformer replacements, relay and breaker upgrades, etc.), can up to double the power transfer capacity within an existing ROW. For the 2% of lines that are too long to benefit from reconductoring and compensation (i.e., >50 miles), sectionalization—i.e., the addition of new substation(s) with active and reactive power generation sources along the line—can help improve voltage and angular stability, allowing grid planners to reap the high-capacity benefits of advanced conductors.
In the business-as-usual scenario without widespread reconductoring and with restricted new transmission build-out, only 16 TW-miles of interzonal transmission capacity are added by 2035, well short of the anticipated transmission capacity needed to support widespread decarbonization and electrification. However, if the build-out of new transmission lines remains at recent historical rates, large-scale reconductoring with advanced conductors can enable nearly four times the interzonal transmission capacity (i.e., across balancing areas of the Regional Energy Deployment System [ReEDS] model ) by 2035 at only a 20% higher total transmission investment. These capacity additions through reconductoring account for nearly 90% of the new interzonal transmission capacity added in this scenario which reaches more than 90% clean electricity by 2035.
Reconductoring with advanced conductors can rapidly and cost-effectively provide substantial increases of transmission capacity in the near-term. Beginning in the mid-2030s, however, greenfield transmission development begins to play an increasingly larger role in new interzonal transmission capacity additions, as opportunities for reconductoring with present-day advanced conductors are exhausted. Given that new transmission linescan often take 10–15 years to complete due to hurdles such as permitting and cost allocation, this indicates that the optimal transmission expansion strategy on the path to full grid decarbonization should leverage large-scale reconductoring with advanced conductors in the near-term, while new lines for long-term needs are concurrently planned, permitted, and constructed. However, we haven’t fully assessed whether reconductoring is sufficient for expanding transfer capacity between transmission planning regions, as it may be hindered by a smaller existing supply of interregional lines to reconductor and cost-allocation challenges.
Today, most power lines consist of steel cores surrounded by strands of aluminum, a design that’s been around for a century. In the 2000s, several companies developed cables that used smaller, lighter cores such as carbon fiber and that could hold more aluminum. These advanced cables can carry up to twice as much current as older models.
Replacing old lines can be done relatively quickly. In 2011, AEP, a utility in Texas, urgently needed to deliver more power to the Lower Rio Grande Valley to meet soaring population growth. It would have taken too long to acquire land and permits and to build towers for a new transmission line. Instead, AEP replaced 240 miles of wires on an existing line with advanced conductors, which took less than three years and increased the carrying capacity of the lines by 40 percent.
In many places, upgrading power lines with advanced conductors could nearly double the capacity of existing transmission corridors at less than half the cost of building new lines, researchers found. If utilities began deploying advanced conductors on a nationwide scale — replacing thousands of miles of wires — they could add four times as much transmission capacity by 2035 as they are currently on pace to do.
That would allow the use of much more solar and wind power from thousands of projects that have been proposed but can’t move forward because local grids are too clogged to accommodate them
Experts broadly agree that the sluggish build-out of the electric grid is the Achilles’ heel of the transition to cleaner energy. The Energy Department estimates that the nation’s network of transmission lines may need to expand by two-thirds or more by 2035 to meet President Biden’s goals to power the country with clean energy.
But building transmission lines has become a brutal slog, and it can take a decade or more for developers to site a new line through multiple counties, receive permission from a patchwork of different agencies and address lawsuits about spoiled views or damage to ecosystems. Last year, the United States added just 251 miles of high-voltage transmission lines, a number that has been declining for a decade.
The climate stakes are high. In 2022, Congress approved hundreds of billions of dollars for solar panels, wind turbines, electric vehicles and other nonpolluting technologies to tackle global warming as part of the Inflation Reduction Act. But if the United States can’t add new transmission capacity more quickly, roughly half the emission reductions expected from that law may not materialize, researchers at the Princeton-led REPEAT Project found.
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With electricity demand beginning to surge for the first time in two decades because of new data centers, factories and electric vehicles, creating bottlenecks on the grid, many utilities are getting over their wariness about new technologies.
“We’re seeing a lot more interest in grid-enhancing technologies, whether it’s reconductoring or other options,” said Pedro Pizarro, the president and chief of executive of Edison International, a California power company, and the chairman of the Edison Electric Institute, a utility trade organization. “There’s a sense of urgency.”