The Future of Smart Grid Transmission: Superconducting High-Voltage Power Lines

To deliver the promised benefits of the smart grid –- stability, seamless interconnectivity, real-time information for customers and grid operators –- the country’s aging, isolated AC grids will have to be replaced by a robust new transmission network. And that future dream looks like it will be tightly connected to a technology called superconducting high-voltage direct current (HVDC) power lines, which are super-chilled to boost capacity and can carry gigawatts of electricity. At least that’s the idea according to companies like TresAmigas and American Transmission Company, which dug into the benefits of the next-gen transmission tech, during an online event hosted by EnergyBiz magazine last week.

On the online panel, Phillip Harris, Chairman and CEO of TresAmigas, and John Procario the President and CEO of American Transmission Company (ATC), took turns describing the failings of the existing transmission system, much of it stemming from the fact that the grid infrastructure is at least 30 to 40 years old. The current interconnected AC transmission system is fated to suffer “diminishing returns” including line losses, system voltage stability, and uncontrolled load flow problems and bottlenecks (congestion that threatens cascading blackouts) explained Harris.

Harris touted HVDC lines as the key to the future smart grid, and Harris said the only way to interconnect large AC power grids that are not synchronized (that is, of different phases) is via HVDC infrastructure. “It’s [HVDC] time has come” said Harris. (For more on superconducting materials that could potentially transmit more electricity with less equipment, see GigaOM Pro).

Harris’s enthusiasm is partly due to the fact that his startup, TresAmigas, has an ambitious plan to link America’s three vast interconnections –- east, west, and Texas –- via a 5-gigawatt, HVDC power line installed at a superstation just outside of Clovis, New Mexico. Wisconsin-based ATC also has a stake in the market. The utility, which only focuses on transmission projects, owns and operates much of the transmission network in the Midwest, and has invested $2.1 billion over the past 9 years to build or upgrade 1,800 miles of transmission lines.

Why HVDC is the Future

There are three principal advantages to using HVDC, Harris said:

Reliability — With the help of power electronics (more on this below), electricity sent over HVDC lines can be precisely controlled. HVDC stations can also connect incompatible AC grids, converting electricity so it can flow in both directions and enabling neighboring power networks to absorb or supply power as needed.

The bottom line — HVDC lines can can carry more power over long distances than a comparable AC link. According to ABB, a 2,000-kilometer-long HVDC line rated at 80 kilovolts loses about 5 percent of the electricity it carries to hear, while an equivalent AC line would lose about 10 percent.

Emergency support — If a natural disaster or other disturbance knocks out power in an AC grid, the “black start” capacbility o HVDC stations can safely supply electricity to blacked-out neighborhoods.

HVDC transmission will be aided by increased use of power electronics to improve system reliability and security and to boost the efficiency and loading of existing transmission and distribution infrastructure, said Harris. Quoting the DOE’s Office of Electric Delivery and Energy Reliability, Harris said presently, only 30 percent of all power generated uses power electronics somewhere between the point of generation and end use. But by 2030, 80 percent of all electric power will flow through power electronics.

How to Get There:

The key to getting these new next-generation transmission lines built that will deliver clean power from far-flung wind farms or concentrated solar power plants, Procario argued, is early and vigorous involvement with all stakeholders –- regulators, media, and the public. We need the equivalent of a political campaign, explained Procario. As some of the negative public reaction to California’s controversial Sunrise Powerlink has shown the clean power industry, you can’t always expect the public to embrace new transmission lines, even if they are delivering clean power. Time and resources need to be invested upfront in public outreach, said Procario, and the costs for this type of messaging pales in comparison to the cost of lawsuits or a drawn-out regulatory proceeding.

Procario also said he supports giving the Federal Energy Regulatory Commission (FERC) “backstop” siting authority (the idea being one agency should have lead authority for permitting on public lands) as well as the authority to determine the cost share of new transmission, especially across regional transmission organization (RTO) borders. As for who actually owns the lines, Procario said that all parties should be open to “unique ownership structures” for new transmission infrastructure because arguments over who owns transmission lines only delay an already lengthy process.

The Barriers

What would a grid upgrade like that cost? Procario said he thought it could be built for $100 billion over the next 20 years. Other data puts the figure much higher — the Brattle Group has said that building out transmission and distribution will cost $2 trillion.

It’s also still early days for superconducting high-voltage power lines. Super-cooled conductors are still years away from the market, Bob Anderson, managing director of the Western Grid Group, told GigaOM Pro last year. At this point just three utilities are using superconducting wires, designed by American Superconductor, in test projects in New York and Ohio, pointed out Anderson.


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