Solar energy may soon eclipse nuclear power — only not in the way we hoped. According to NASA, the planet will soon face an outbreak of powerful solar flares capable of collapsing global power grids. Were this to happen, the world's reactors could be left to run wild, overheat, melt down, and explode. As this is being written, the strongest solar storm in six years is barreling toward the Earth at 4 million miles per hour.
The sun's magnetic cycle peaks every 22 years while sunspot activity crests every 11 years. Both events are set to peak in 2013. Coronal Mass Ejections (CMEs) trigger geomagnetic disturbances (GMDs) — tides of high-energy particles that can disrupt power lines. Since the 1970s, the array of high-voltage transmission lines spanning the US has grown tenfold. NASA warns these interconnected networks can be energized by a solar flare, causing "an avalanche of blackouts carried across continents [that] … could last for weeks to months." A National Academy of Sciences report estimates a "century-class" solar storm could cause 20 times the damage as Hurricane Katrina while "full recovery could take four to ten years."
There have been two massive CMEs over the past 153 years. The 1859 "Carrington Event" irradiated Earth for nine days, causing the Northern Lights to erupt over Hawai'i. On May 14, 1921, a GMD lit up northern skies as far south as Puerto Rico. Both flares disrupted telegraph communication around the world, causing some equipment to burst into flames.
But twentieth century telegraph systems were more resilient than today's electronics. Solar flares can bake the circuitry that controls aircraft, banking, GPS, radio, TV broadcasts, iPods, and the Internet. As NASA solar physicist Lika Guhathakurta put it: "A similar storm today might knock us for a loop."
On March 13, 1989, a 90-second solar blast slapped HydroQuebec's transmission system and left six million Canadians without electricity for nine hours. The storm cooked transformers in Great Britain and triggered 200 "anomalies" at oil-, coal-, and nuclear-fueled facilities across the US, even melting a transformer at New Jersey's Salem 1 reactor.
A Carrington-sized GMD could damage thousands of extra high voltage (EHV) transformers around the world. These transformers can weigh up to 300 tons and cost more than $1 million. Power grids cannot operate without them. Because each is custom-built to regional specifications, procuring new EHVs can take up to three years. Rebuilding a damaged grid could take decades.
That could be the best-case scenario. More worrisome is imagining what would happen to nuclear power plants that are reliant on a functioning electrical grid.
A 2011 Oak Ridge National Laboratory report warned of a 33 percent likelihood that a solar flare could lead to "long-term power loss" over a nuclear reactor's 40-year life. With 440 nuclear power plants in 30 countries — and 250 research reactors — there are nearly 700 potential Fukushimas waiting to be unleashed by a super flare.
Faced with a grid collapse, nuclear plants must rely on backup power to cool reactor cores and spent-fuel ponds. But the NRC only requires eight hours of battery power and enough fuel to run emergency generators for a week. Restoring outside power to Fukushima's damaged reactors was a daunting task even when Japan had a functioning grid to fall back on. If the Sun sends a geomagnetic tsunami sweeping across Earth, it could become impossible to provide any form of traditional power.
NASA has proposed a "Solar Shield" to detect incoming CMEs and warn operators to shut down the grid until the danger passes. Unfortunately, the plan is experimental and has never been field-tested. The US could protect its grid by spending around $1 billion to “harden” 350 key EHV transformers and stock blast-proof warehouses with replacement parts. Transformers could be protected with ground resistors. Costing about $40,000 each, they could be installed on 5,000 critical transformers for less than $200 million — about one-tenth the cost of a B-2 bomber.
In August 2010, the US House of Representatives unanimously approved HR 5026, a bill that would have protected the grid against geomagnetic storms. But the Senate failed to act. Last June, the US and UK announced plans to mandate “controlled power cuts” to protect the grid — but that's only two countries. Until every nuclear nation is prepared for grid collapse, the inevitable cascade of core meltdowns could mark the end of the industrialized world as we know it.