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Sun Cycle Threatens Electric Grid

​AROUND FEBRUARY 2013, the sun will ride its 11-year cycle upward toward solar maximum. During these periods, solar flares increase, and the ions generated by these massive solar explosions can create geomagnetic storms that interfere with the earth’s magnetic field.

Small geomagnetic storms are common, but cause only temporary problems in electronic equipment and small disturbances in radio waves. By contrast, some experts warn that a severe storm could cause extra high-voltage (EHV) transformers to fail catastrophically, plunging the United States back into the power equivalent of the early 19th century.

Even though NASA predicts the weakest cycle in 85 years, those who say the threat is still serious are concerned that the power industry and the U.S. government have done little to harden vulnerable EHV transformers. The power industry, however, asserts that the problem should be studied more thoroughly before companies are forced to invest in expensive and untested hardening measures.

Chuck Manto, head of the InfraGard National EMP Special Interest Group, says that a big solar storm is like a knife pointed at the United States’ jugular vein, the electrical grid. A large solar storm would produce geomagnetically induced currents (GIC) in the ground, which would saturate EHV transformers. This could cause hundreds of them to fail simultaneously, knocking down the electrical grid and producing widespread and long-lasting blackouts, according to multiple government reports. All other critical infrastructures dependent on electricity—such as banking, communications, information technology, sanitation, and water—would topple as well. If enough EHV transformers sustained damage simultaneously, manufacturing replacements and restoring power could take months, because no one stockpiles this expensive equipment.

“It would be arguably one of the worst natural disasters the country could face,” says electrical engineer John Kappenman, owner of Storm Analysis Consultants and an expert on the threat of geomagnetic storms to the electrical grid. “Electricity is so important to our society. We cannot sustain our population without a semblance of a functioning power grid.”

Giant geomagnetic storms have occurred throughout the earth’s history. Two for which details exist have been studied.

In the case of one storm that occurred in 1921, analysts compared its magnetization, or Bh, curves with the Bh curves of more recent storms. Analysis of another storm that occurred in 1859 is based on qualitative and anecdotal evidence of the storm's effects on electrical systems and auroral observations of the northern lights as detailed in news reports that have been preserved.

Extrapolating the effects of those historical incidents to today in light of the effects of smaller but more recent storms gives an indication of how vulnerable today’s infrastructure may be to disruption. For example, in 1989, a geomagnetic storm caused the Hydro Quebec power grid to fail in approximately 90 seconds, causing a nine-hour blackout that left millions without power. According to modeling by Kappenman, if a geomagnetic storm the size of 1921 hit today—approximately 10 times the size of the 1989 event—more than 350 EHV transformers could be destroyed, leaving more than 130 million Americans without power. Given the magnitude of the disruption, restoration could take months if not years, says Kappenman.

The North American Electric Reliability Corporation (NERC), whose mission it is to ensure the reliability of the bulkpower system, considers Kappenman’s modeling too dire, says Mark Lauby, NERC's director of Reliability Assessments and Performance Analysis. NERC is currently working on its own tools so that it can develop, in its view, a more realistic projection of which transformers could fail in such a scenario.

Critics say utilities should harden the most critical transformers, primarily those supplying electricity to cities, in the short term. Utilities should be adding in other protections and redundancies over time.

“[Utilities] can put resistors to ground at the transformers, which will help to reduce the current flow that is induced by geomagnetic storms,” says Yousef Butt, a scientific consultant to the Federation of American Scientists and a physicist at the Harvard-Smithsonian Center for Astrophysics.

Another relatively cost-effective option for utilities is installing surge arresters on extreme high-voltage transformers, says Peter Pry, president of EMPact America. Pry worked on the congressionally authorized Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack. With surge arresters, “If the energy is coming in in a way that it shouldn’t be, the sensor will [detect] it and shut [the transformer] down,” thereby saving it, he explains.

The good news is that these technologies are available, says Kappenman. He estimates that it would cost $1 billion to harden all high-voltage transformers in the United States. That’s cheap compared to what it costs to recover from even a small disruption. For instance, the August 2003 Blackout that enveloped parts of the Midwest and Northeast cost between $4 billion and $10 billion, according to the Department of Energy.

Another solution would be for utilities to begin stockpiling high-voltage transformers. Then, if a critical transformer failed, another one could take its place in the grid. But EHV transformers are costly and America no longer manufactures them. All are imported and can take almost 3 years to be manufactured and delivered at a price tag of about $10 million, according to Kappenman.

The long-term solution is requiring GIC standards for new transformers. “The problem is the power industry has never had a design code that takes this threat into consideration,” Kappenman says.

Critics want Congress to step in with mandates, but NERC’s Lauby says it’s unrealistic to expect utilities to spend billions of dollars on transformer hardening and system upgrades without hard evidence that a giant geomagnetic storm will spell doom. “Industry needs to be convinced and demonstrations need to be carried out,” he says.

He notes that the risks from geomagnetic disturbances are not uniform throughout North America. They disproportionally affect the northern latitudes.

Another concern is that transformer hardening could cause unforeseen and negative consequences. “We have to make sure that no harm is done when we deploy [hardening] devices,” Lauby says.

NERC spokeswoman Kimberly Mielcarek points out that the regulators have not been ignoring the issue. She points to the joint NERC-DOE report on geomagnetic disturbances in June 2010 and notes that the corporation has established the Geomagnetic Disturbance Task Force and recently held a technical conference on the threat that included critics like Kappenman and Pry.

Sometime in the first quarter of 2012, NERC will issue another report on geomagnetic threats to the electrical grid with recommendations for operations and planning. That may prompt industry “to work toward standards that they would all agree to follow,” Lauby says.

But that could take up to two years, and such standards would likely only require utilities to determine how vulnerable they are to geomagnetic disturbances. By then, February 2013 will have come and gone, answering the question definitively outside of the lab.