One night, a little more than a thousand years ago, Native Americans in North America were startled to see stars fade away as darkness into a dusky daytime long before morning. They weren’t sure what it foretold or what to make of it, but they prepared for the worst, even as they marveled at the accompanying auroral display.

The show was visible the following night as well, but the skies were far less bright. Soon all was back to normal. These American Indians were left with memories of this seemingly spiritual occurrence, but there were no other signs that anything in their world had changed.

As we now know, this was a solar flare and coronal massive ejection (CME) event, complements of the Sun. The only impact was on the senses since these manifestations don’t affect biological organisms.

Fast forward about 800 years to September 2, 1859, when a similar event was observed in the skies. Eighteen hours before this solar flare-CME light show began, though, astronomer Richard Carrington was working in the Town of Redhill, 35 kilometers south of London. Carrington was tracking a sunspot when he observed a “white hot flare” on the Sun’s surface that lasted for several minutes.

He was observing the birth of another CME destined for planet Earth. But when this CME reached the lower levels of Earth’s atmosphere, the impact of the resulting geomagnetic storm was a bit more serious than the event 800 years earlier.

The 1859 CME wasn’t necessarily more powerful than the earlier one, but there was one major difference. The Earth had changed in the interim. Humankind had discovered and harnessed electricity. We had electric motors, circuitry and telegraphs and the CME’s magnetic field disrupted the magnetic fields of these electric circuits.

But still, the impact of the CME event wasn’t catastrophic. The most remarkable aspects were more curiosities than a problem. Some telegraph operators received shocks and minor burns. Their devices momentarily seemed to be self-powered, with some reportedly continuing to run and transmit even after they were hastily disconnected.

Overall, though, citizens of the world once again marveled at the oddly-lit night and the incredible auroral displays usually only seen near the north and south poles. Another CME episode came and went in the history books with little damage done.

Next time, however, we may not be so lucky.

Solar Flares and Ejections

While many people fret about “solar flares,” the real danger is from CMEs. Both are triggered by eruptions on the sun. They may occur simultaneously – a CME often accompanies a solar flare, and a CME won’t happen in the absence of a solar flare. The stronger the solar flare, the more likely it is that it will be accompanied by a CME.

The emissions of the two are quite different. In the case of solar flares, the sun simply emits radiation – light that reaches the Earth’s atmosphere at the speed of light in about eight minutes.

But when the upheaval on the Sun’s surface is more intense, solar matter in the form of charged energy particles is also ejected into space. If the CME happens to be propelled precisely in the right direction to collide with the moving Earth, the plasma cloud will reach deeper into Earth’s atmosphere than the light energy of a solar flare … and with far more destructive results.

NASA helpfully describes the difference between these two phenomena by comparing the situation on the Sun with firing a cannon. When a cannon is fired, the muzzle flash can be seen far and wide. That’s analogous to a solar flare with the light traveling at the speed of light. This is followed by the expulsion of the cannonball itself, which has a far more targeted and localized affect. And as with CMES, the impact of the cannonball happens at a far slower rate than the speed of light.

Don’t take the analogy too far, though. The CME doesn’t make a physical impact on the face of the Earth. The plasma, the concentrated cloud of charged ions, makes its way into our atmosphere and interrupts and interferes with other magnetized electrical charges.

The CME plasma that arrived a thousand years ago didn’t encounter any electrical devices so it simply reacted with the oxygen and nitrogen in our atmosphere to create dim light and extensive aurora displays before it dissipated with no harm.

Will a Major CME Event Happen Again?

CMEs occur in the context of the Sun’s 11-year solar cycle when its activity peaks and declines. We’re near a peak in the next year or so. During this brief period, the sun’s magnetic field lines are especially chaotic, with the rapid acceleration of charged particles that can be ejected as solar flares and CMEs.

Direct-hit CME events like the ones in 1000 CE and 1859 are the culmination of a series of worst-case scenarios.

When a CME contains atoms, electrons, and ions with sufficient energy … and the ejection is pointed precisely so that it will impact Earth (itself a moving target in orbit) … and the magnetic fields of the CME and Earth are “anti-aligned,” the occurrence will indeed spell trouble – more than just night lights and auroral light shows. But we’ll get to that in a minute.

In most cases, though, the CMEs emitted by the Sun have relatively low energy, they’re off target, and/or they’re deflected by Earth’s magnetic shield.

The National Oceanic and Atmospheric Administration has estimated that a CME “Carrington Event” could be expected to impact the Earth approximately once every 500 years or less.

We reportedly dodged a bullet in July 2012 when a powerful CME ejected in our direction, passing through a point in space just nine days away from where we were orbiting at 30 kilometers per second.

Knocking out Power Stations and Grids

In the years since 1859, our electrical infrastructure has become widespread and interconnected. If a CME’s massive geomagnetic-induced surge of current encounters any of the infrastructure of our electric grid system, we’ll see explosions, fires, and blackouts at our power stations and substations that could leave major areas without electricity. Extend that impact to multistate regions or even worldwide, and the results could be unimaginable. But we had better imagine them because “once every 500 years” can’t be ignored.

Disrupting Communications

As if losing all electricity wasn’t enough of a disaster, CMEs and significant solar flares can disrupt important communications systems.

Located in the Earth’s upper atmosphere, the ionosphere serves as a refractory surface that enables long-distance shortwave communication, a communication method known as “skywaving.” Solar flares affect the stability of the ionosphere and put this communication at risk.

GPS systems rely on a stable ionosphere for radio transmissions. CME disturbances can send these measurements off-kilter by dozens of feet, with disastrous consequences for some sensitive systems.

Skywaving is used in aircraft, military and other communication systems that can’t utilize private-sector, satellite-based communication services. Fortunately, more and more communication satellites are being placed in low-Earth orbits, supporting a more reliable, extended skywave refractory system.

But then again, Earth-orbit satellites are easily damaged by energy bombardment from significant solar flares and CMEs. Communications satellites in upper geosynchronous orbit are especially vulnerable.

Secondary Impacts

Without electricity for an extended period of time, our lifestyle as we know it would be completely disrupted and we’d become immersed in the literal and figurative dark ages.

Backup generators would run out of fuel in a matter of hours or days. After that, to put it mildly, the Internet would be “down.” And since more and more of our financial, healthcare, communication, utilities, and transportation systems rely on the Internet and Internet-empowered blockchain, these systems would go down as well.

What was daily life like in 1830? We’d all better read up on it because we may need to live in that world for weeks at a time. Many won’t survive it, unfortunately, and succumb to floods, cold, heat, illness, lawlessness, crashes, and hunger.

What Can We do to Prevent a Future CME Disaster?

We can’t prevent a one-in-500-years, Earth-impacting CME, but we can and must make some adjustments to our systems in order to limit or prevent the kinds of worst-case scenarios described above.

We’re already making progress in some important areas … but much more can be done.

Early Detection

Fortunately, CMEs don’t travel at the speed of light; they take anywhere from 15 hours to several days to reach Earth. We’ll have time to see them coming if we have appropriate Earth- and space-based detection systems in place so we can take protective measures. We need to continue to develop our early warning systems like that at the National Science Foundation’s Daniel K. Inouye Solar Telescope on Maui. Earlier warnings about possible CMEs give power plant operators an opportunity to appropriately prepare for a likely surge and give satellite operators time to put their satellites into safe modes.

Electrical Grounding/Earthing

As basic as it may sound, electric grid infrastructure can be protected from CMEs if they’re properly grounded using copper or other conductive materials that send the surges safely into the ground. We need to ensure that every power plant, substation, and other critical pieces of power grid infrastructure is protected in this way.

If we don’t take these actions, a major CME event might not destroy the Earth, but in just a few hours, it could bomb us back into the pre-technology stone ages.

Although solar power represents the fastest-growing share of new electricity capacity, it still accounts for just three percent of the total U.S. electricity generated. And only three percent of homes in the U.S. have solar panels, compared to 20% in Australia.

Two companies, in particular, are trying to raise that U.S. number – one rooftop at a time.

Tesla is arguably the most influential and visible of the two, having purchased SolarCity, the early industry leader in rooftop solar panel systems, in 2016.

Sunrun, founded in 2007, is the other major player. For years it has been the leading supplier of residential solar panel systems and it widened that lead after its purchase of Vivint Solar Inc. in 2020. It’s possibly being overtaken by Tesla, though, based on the megawatts of solar Tesla has deployed over the past 12 months.

Rooftop solar panel technology is an example of a distributed energy resource (DER), meaning it’s a localized, relatively small power source that’s located apart from a major, centralized power plant. DERs can be a single home or a mini, localized, renewable power station (solar or otherwise) serving a neighborhood or community.

Energy Independence at Home

Tesla, especially, is touting a comprehensive approach that links its rooftop solar panels to its energy storage battery product called Powerwall. In fact, in true Elon Musk style, the company recently announced you can’t buy one without the other. Essentially, Tesla is selling a “powerplant” home kit that generates and stores power for use in that structure, and delivers excess power back into the electricity grid – known as “net metering.”

While less splashy, Sunrun also offers a similar battery-enabled home energy storage system.

At-home storage of power captured from solar panels is critical, relatively recent expansion of solar residential technology services. It’s especially piquing the interest of homeowners in California and Texas who last year faced extended power outages due to wildfires and ice storms, respectively. Blackout-proofing is a powerful sales pitch!

The economics of residential solar are getting better, too. Installation costs continue to go down, and late last year the federal investment tax credit of 26% of the cost of installation was extended by Congress for another two years. A similar credit is available for commercial building solar panel installation.

The Bigger Picture

The rooftop solar technology addresses two major future-related situations. First, there is an increasing electrification of our life, including our cars and our appliances. Second, we clearly need to minimize carbon emissions from traditional power generation in the face of climate change trends.

In short, we need more clean electricity and that means we need more clean electricity producers – large and small, in other words, solar farms and solar roofs.

But technology breakthroughs, societal imperatives, and government bureaucracies don’t always work in lockstep. For many years, state and local permitting delays for rooftop solar panel installation have been a concern and an anchor on the residential solar industry. However, a new federally funded web app available to local governments may help with that. California is an early adopter.

The Trends are Up

Thanks to those natural disaster-driven blackouts, and no doubt also to homeowners with time and cash on their hands during the pandemic, solar panel installation was up 43% in 2020 compared to the previous year, according to the Solar Energy Industries Association (SEIA). That produced 19.2 gigawatts of new energy capacity – and one gigawatt can power 190,000 homes. The U.S. currently has about 97.2 gigawatts of installed solar capacity and SEIA predicts that by 2030, solar installations will quadruple from current levels.

And the Future is Up Too – Literally

We’ve only scratched the surface when it comes to capturing solar energy with our panels. The panels themselves are being improved. Experts say that many of the early panel systems in use today are less than 15% energy efficient. They’re stationary and can’t be adjusted to follow the sun. Breakthroughs in construction and materials will improve the efficiency of newer models.

After all, there’s a lot more solar energy out there, and up there, for the taking. The earth is blasted with more than 173,000 terawatts (one terawatt is 1,000 gigawatts) of solar energy each year – 10,000 times more than we need.

The challenge is to capture some of it and transform it into electricity. There’s some amazing research underway to examine different ways to do this. In next week’s column we’ll look at some that seek to capture solar energy even closer to its source.

In the meantime, Sunrun, Tesla, and others are doing their best to make sure that no ray of light that hits a rooftop is wasted. It’s a fun competition to watch. We all know Elon Musk and his take-no-prisoners approach to markets and competition. Sunrun’s CEO Lynn Jurich has been equally successful taking a different tack, seeing allies in people from all sectors of the energy industry.

Both see the solar rooftop market at a tipping point, where investment in solar energy technology has an incredible upside.

Who will be the winner? We all will.