July 22, 2009
Not long ago, the notion of adding reliability and intelligence to utility operations seemed arcane and dull. Now it has become vogue. The latest such advance is in the area of reducing transmission line losses and thereby increasing reliability.
The so-called high-temperature superconducting cable can virtually eliminate the resistance to electricity flow, thereby greatly increasing the efficiency of the wire. And while the technology is now expensive, government agencies are pitching in and trying to get those next generation wires into the mainstream. In time, it will succeed. The demand for power will not abate and will therefore necessitate the deployment of cutting-edge tools to enhance grid security.
"As the utility industry invests more money in infrastructure, it will seek new ways to become productive," says Dave Bryant, vice president of CTC Cable Corp. in Irvine, Calif. "The superconducting cable technology will help improve the economic viability of all utility projects, including renewables."
According to the U.S. Department of Energy, more than 7 percent of the electricity transported across the wires is lost because of resistance in current copper technologies. At a time when the nation is concerned about fuel supplies and air quality, it is a good investment and would ultimately result in $16 billion a year in savings, it says. Altogether, high-temperature cables can conduct about 10 times the amount of power as those comprised of copper wire.
Superconductivity power equipment typically will be half the size of conventional copper technologies. The Energy Department says that about 2,200 miles of existing underground cables are quickly becoming outdated and could be replaced with high-temperature superconductive lines.
It will be an expensive undertaking, however, because 65 percent of the content used in high-temperature wires is silver. As a result, the cost of a superconductor cable can be anywhere from two to four times the cost of a conventional copper cable. But manufacturers say that they expect the cost to keep falling over time.
The technology is now largely in the testing phase. But the results have been positive. And as the cables mature and prices subsequently drop, experts suggest that they will become increasingly feasible in the utility world.
"The future power grid will likely incorporate superconducting power equipment for specific applications where physical space and capacity are major issues," says research firm EPRI. "Superconducting power cables hold promise to increase transmission capacity while simultaneously reducing spatial footprint and right-of-way requirements."
National Mission
Indeed, the second-generation superconducting cable technology is one solution to the challenging task of providing sufficient electric power to densely populated areas. Burying cable and acquiring rights-of-way are prohibitively expensive, often representing three-quarters of the cost of such projects.
If superconducting tools are to break into the mainstream, however, they must become affordable. That's why the Energy Department has allocated $57 million for research and development for those projects while industry has agreed to put up $60 million.
The agency has joined forces with the Long Island Power Authority by allocating $28 million of the $58 million cost of a project there. That is a 138 kilovolt cable system that runs nearly half a mile. It is the first high-temperature superconductor cable at a transmission site. Other such wires have been used at distribution sites, which are characterized as lines that are 60 kilovolts or less.
The Department of Homeland Security, meanwhile, says that part of its role is to ensure the electricity keeps flowing in major commerce centers. To that end, it is funding $25 million of the $39 million price tag for such technology in New York's financial district. Con Edison is installing the first 50 meters of a 300-meter project and if all goes well, the full project would be completed in 2010.
The Energy Department is also partnering with American Electric Power. That is a $9 million cable extending 200 meters and delivering 50 megawatts of power to 8,600 industrial, commercial and residential customers. The system, built by Southwire, has operated successfully since its installation in August 2006.
"Our partnership with Southwire has allowed us to test advances in superconductivity and cooling design on our system with virtually no interruption to customers," says Michael Heyeck, AEP senior vice president of transmission.
Governments can either directly or indirectly support these new technologies. A utility may have a request for a new transmission network denied. But with superconductivity technologies, utilities could use their existing rights-of-way and at least double their current capacity. Or, conversely, regulators may give utilities making such investments the right to recoup their costs and then to earn a fair rate of return.
Utilities are hesitant, however, to pay for the construction of superconducting transmission lines without some regulatory assurances. And that's why public policy is now providing a number of incentives to invest in smart grid projects that may not have an immediate payback but which will ultimately increase productivity.
It's all part of the national mission to create a modern grid that can deliver reliable and cleaner power supplies. The technology works. But the cost must still fall. As the industry builds experience and economies of scale are formed, high-temperature superconductivity will take the electricity delivery system to a new level.
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