By: Jason Fordney |
Geomagnetic storms can affect power prices and reliability of the grid even in the absence of a blackout and better space weather forecasting could improve the ability to assess vulnerability of the grid, researchers have concluded.
Geomagnetic storms, also known as solar storms, are receiving increased attention among industry and regulators, but the conversation has focused on the impact of blackouts resulting from solar storms, such as occurred in 1989 on the Hydro Quebec grid.
The Federal Energy Regulatory Commission on Thursday will begin a rulemaking related to geomagnetic disturbances, in the wake of a massive effort by reliability officials to assess the danger they represent.
The scope of the FERC effort is not yet known, but FERC member Cheryl LaFleur in May said the current situation calls for national standards to protect against solar storms.
Research indicates that space weather has effects on electricity markets even without any related blackout, said economist Kevin Forbes of Catholic University in Washington, who teamed up with NASA physicist O.C. St. Cyr on the research funded by the National Science Foundation.
When electromagnetic particles are released by the sun in association with solar flares, the energy interacts with the Earth’s magnetic field, causing geomagnetically induced currents, or GICs, that can overload transformers.
“What the GICs do is they increase the consumption of reactive power by the transformers,” Forbes said in an interview. “That’s not just my opinion, that’s what the literature says.”
Forbes’ work, published in five peer-reviewed papers, indicates that when many variables are accounted for, there is a correlation between a measure of solar activity and adverse power system conditions such as transformer overheating and reactive power deficiencies. The analysis did not use simple correlation analysis to arrive at this conclusion, but a statistical method that controls for expected system conditions, he said. This modeling approach could be used to forecast the vulnerability of the power grid to space weather.
“When you have these price spikes?I believe that’s a GIC event ? that’s what my data tells me,” Forbes said.
Reactive power is power that is needed to keep the system functioning, maintaining the voltages required for system stability and consumed by transmission lines, transformers and other equipment on the grid. Geomagnetically induced currents can lead to overheating problems in transformers, leading to spikes in transmission losses and real-time prices. The GICs also cause spikes in the amount of reactive power consumed by the transformers.
The research also indicates that the system’s vulnerability to solar storms varies, and at times when the system is most vulnerable to reactive power disruptions, even relatively small solar storms can have an effect.
Forbes examined one dramatic price spike in the New York Independent System Operator on January 21, 2005, when the real-time price for electricity spiked dramatically to almost $900/MWh. This event was aligned “virtually perfectly” with a geomagnetic disturbance, and power systems in Scandinavia were affected at the exact same time, Forbes said. He also said the data indicates that solar activity contributed to well-publicized loop flows around Lake Erie.
He said there is evidence that geomagnetic disturbances contributed to delivery issues at interfaces between British Columbia and the US, between California and Oregon, and between Michigan and the PJM Interconnection.
Forbes said the research could better inform system operators about the space weather vulnerability of their systems and allow them to make better use of space weather forecasts.
PJM Executive Director for Operations Support Frank Koza in an interview said he is familiar with Forbes’ research.
As to the accuracy of the findings, Koza said “I’m not a statistician,” but he added that “I have to believe there is a statistical correlation that he’s determined.” However, Koza said that some of the data analyzed in the research could have been affected by actions PJM was taking in response to solar activity.
“Part of it is explainable from that perspective,” Koza said. Forbes said he agreed with Koza but added that this does not negate the data, and said that he had included in the data occasions when PJM had enacted its solar magnetic disturbance measures.
About 10 sensors are currently installed on the PJM grid, with more in the works, Koza said. When PJM detects sensor measurements above a certain level, it will redispatch generation, reduce flows and invoke other operating procedures. Koza said at this time PJM views the research as informational and does not plan to change its current procedures in reaction to the findings.
A North American Electric Reliability Corp. task force issued a report in February saying that solar storms are a serious concern, but NERC said it does not think a severe geomagnetic disturbance could cause failure of a large number of extra-high-voltage transformers and result in full-grid outages lasting months or years. NERC concludes the greatest risk of a severe disturbance would be “loss of reactive power support, which could lead to voltage instability and power system collapse.” NERC said the most likely duration of resulting outages is hours or days.
The NERC task force report said that new reliability standards might be necessary to address the threat of geomagnetic storms. Other than solar activity, the concerns over geomagnetic disturbances also include hostile attacks that could generate an electromagnetic pulse and disrupt the grid.