My Opinion: There’s a Practical Way to Fix the Electric Grid Bottleneck

Ed Brown

We are in an era of technological revolution: Rapidly expanding applications of AI, distributed renewable energy sources, electrification of transportation, sustainable buildings, and smart everything, to name a few areas. One thing all of these need is more electricity — lots more. There are a variety of approaches to satisfying the increased demand, the most significant of which is to add renewable sources to the mix. But there’s a problem with adding renewables, and it’s not the lack of renewable sources — the problem is how to connect them to the grid. According to a GridLab report  , “Over 2 TW of available generation and storage resources today remain untapped, awaiting grid access in interconnection queues.”

And assuming these resources will eventually be able to connect to the grid, there’s not enough cable to deliver the increased electricity to end-users. According to the MIT Center for Energy and Environmental Policy Research ( CEEPR  ), “…the U.S. lacks the necessary transmission infrastructure to deliver more power. The Department of Energy (DOE) has estimated that by 2035, transmission infrastructure will need to grow by 57 percent. Despite this, high-voltage transmission construction has slowed from an average of 1,700 miles built per year between 2010 and 2014 to only 55 miles built in 2023.”

And existing power lines are being stressed by weather extremes, fires, and floods.

Fortunately, there’s a practical solution to all of these problems: replace the existing transmission cables with higher-current-carrying capacity cables to cover near-term needs while at the same time developing long-term solutions. It makes a lot of sense but as with every innovation there’s resistance to implementing it. Especially with utility companies who are very cautious about change.

Reconductoring

There is a technique called reconductoring, where standard transmission cables can be replaced with cable that has about twice the current rating. The new cables would be the same diameter as the old, so the utility poles would not have to be replaced, and the complicated and time-consuming process of negotiating rights of way would be bypassed. These new high-current cables are being manufactured in the U.S. and have been used in several locations.

What Is the Secret to the New Cables?

The answer can be found in a GridLab report  , “2035 and Beyond — Reconductoring with Advanced Conductors Can Accelerate the Rapid Transmission Expansion Required for a Clean Grid.” The report is based on research done at the University of California, Berkeley.

The construction of high-voltage power line conductors has not changed much since the early 1900s. Called Aluminum Conductor Steel Reinforced (ACSR) cable, it consists of an inner core of steel strands for strength and rigidity, surrounded by an outer core of aluminum conductors. In the 2000s, new composite materials were developed that could replace the steel core. Since these new cores are smaller and stronger than steel, there is room for more of the cable’s diameter to be filled with aluminum conductors. And the conductor’s cross-sections are trapezoidal rather than circular, which also increases the total amount of aluminum. Current ratings on the new composite core cables are roughly double that of the traditional ones. And maximum operating temperatures are 180 °C compared to 75 °C.

What Can Reconductoring Do for Us?

It has the advantage that it can be deployed relatively quickly, in only a year or two. While in contrast, according to the GridLab report, “new transmission lines can often take 10–15 years to complete due to hurdles such as permitting and cost allocation.” And of course, new lines require the building and installation of new towers.

Time is of the essence if we are to meet our growing electrical energy needs. A report  by the Department of Energy predicts that “transmission capacity must increase by up to 128% within regions and by 412% inter-regionally by 2035 to accommodate the high load growth and high clean energy growth.”

There are other advantages to the new cables besides the doubling of the amperage capacity. According to the GridLab report, “Results indicate that other advantages of advanced conductors may include improved resistance and resilience to bending failure, oxidation, ultraviolet (UV) rays, galvanic corrosion, and general environmental damage… Some advanced conductors also embed an optical fiber to monitor line temperature and elongation in real time, enabling validation testing after installation, dynamic line rating, or insulation-based wildfire protection.”

Is Reconductoring a Practical Technology?

It’s now being used at scale, more than 145,000 km worldwide, in Belgium, Netherlands, Italy, India, and China.

In the U.S., as far back as 2005, Minnesota utility Xcel Energy, urgently needed to bring more electricity into the Twin Cities, and it chose reconductoring. According to the GridLab report, the construction was completed in eight weeks.

In a 2016 reconductoring project, in the southeastern Texas Lower Rio Grande Valley, which was the longest in the world at that time, the work was even done while energized, so there was no disruption to the consumers. The $225 million project was completed several months ahead of schedule and millions of dollars under budget.

Summing Up

The path forward is clear — to meet the looming electrical supply crisis, we should use reconductoring for our near-term requirements while at the same time planning the needed expansion that will meet our long-term needs.

While I think this is the obvious path forward, there are significant obstacles. A companion report  to the GridLab technical analysis outlines some of the issues:

“Though advanced conductors are an established technology, the utility industry has yet to adopt them at a scale consistent with their potential. We interviewed more than a dozen industry stakeholders, including utilities, regulators, and system operators, to better understand barriers to the wider adoption envisioned in the UC Berkeley/GridLab report. Despite advantages like better efficiency, higher capacity, and improved reliability and resilience, the higher up-front cost of advanced conductors makes it difficult for utilities to justify wide, proactive use under current regulatory practice. Industry unfamiliarity with the technology, lack of comprehensive regional planning, and unclear permitting processes have exacerbated these issues. Other barriers to implementation include aging infrastructure that needs remediation or replacement, supply chain bottlenecks in transformers, and workforce limitations.”

As in so many cases, even though the technical advantages are clear, implementation can be a major hurdle.

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