The aurora borealis was visible in Boulder on May 11, as the strongest geomagnetic storm in two decades brought the northern lights to town. While many were outside trying to capture the event, scientists at the National Oceanic and Atmospheric Administration center in Boulder, or NOAA, were tracking the solar storm for its potential impacts on the electric grid.
“This was a historical event,” said Shawn Dahl, a senior space weather forecaster at NOAA. “We did not want to see any failures in our technologies and infrastructure that we rely on.”
Dahl said NOAA scientists were in talks with representatives from the communication industry, FEMA (the government agency responsible for helping Americans recover from disasters) and staff in the White House situation room to ensure protections were in place.
The concern is that such events can put electric current on high-voltage transmission lines and disrupt the magnetic circuit in transformers, potentially leading to power outages. A 1989 geomagnetic storm cut power for millions in Québec for nine hours. The most intense storms could have far greater impacts.
An 1859 event, the most intense on record, put so much current on telegraph lines that several telegraph stations caught fire. The level of the 1859 storm is a benchmark for what experts would like our electric grid to be prepared for, though it’s not there yet. What effect such an intense storm would have on our electric grid today is uncertain. If it caused blackouts, Dahl said, those outages could last far longer than a few hours.
“This would not be for a city block, this would not be for a huge metropolis, this would be for whole states,” Dahl said. “This could mean days or weeks without being able to get the power back up.”
Yet Dahl said the only lines affected are the high-voltage transmission lines. So if municipalities had power sources locally available, such blackouts could theoretically be avoided.
Lex Telischak, the City of Boulder’s electrical senior engineer, validated that local storage systems, like microgrids and battery backup systems, could offer respite in the case of an intense geomagnetic storm. Microgrids have taken on new interest in Boulder after Xcel Energy preemptively de-energized its lines during a windstorm in early April to reduce the risk of wildfire. Thousands of Boulderites were without power for days. Microgrids could theoretically have blunted that impact, and it seems they might have the added benefit of providing resiliency from solar storms.
“Either way, having backup energy systems that can isolate to serve their respective critical loads is almost always a plus when it comes to reliability of electricity,” Telischak said.
The introduction of microgrids into Boulder’s system will have many more benefits for wildfire, wind or Xcel-induced outages in the short term than their protection from solar-induced outages. But geomagnetic storms are still worth considering.
“We are overdue,” Dahl said, “for an extreme-level event.”
