A list of the top risks to data centers might include malicious attacks, hurricanes and other weather-related disasters, earthquakes, political instability, and so on. One threat that may fail to appear on the list, however, is solar flares. Solar flares—or coronal mass ejections (although there is a difference, we’ll group the two events under the term solar flares for simplicity)—are events in which the sun flings large (i.e., larger) amounts of energy and particles into space. This discharge, if it hits the Earth, can produce stunning phenomena like the auroras, but it can also wreak havoc with electrical systems. And that means trouble for the data center.
Effects of Solar Flares/CMEs
The charged particles emitted during a solar flare event (particularly, a coronal mass ejection, or CME) create strong magnetic fields owing to their high velocities. These fields induce currents in conducting materials—like cables that carry electricity. In particular, a Lloyd’s report (“Solar Storm Risk to the North American Electric Grid”) notes that “one serious threat to the reliability of electric power is geomagnetic storms—severe disturbances caused by solar storms in the upper layers of our atmosphere that induce currents in long conductors on the Earth’s surface, such as power lines. These additional currents can overload the electric grid system to trigger voltage collapse, or worse, damage a significant number of expensive extra-high voltage transformers.”
Eric Gallant, Consultant Energy Management Services at Schneider Electric, said that “the probability of a significant solar event that affects our power grid is very high. Our sun is currently in a very active phase. Solar flares and coronal mass ejections (CMEs) are occurring on a regular basis. If the energy from one of these solar events were to squarely strike the Earth’s magnetic field, we could experience widespread electrical surges and blackouts.”
According to NASA, some potential effects of the currents created by solar flares include tripped circuit breakers (a less worrisome result), overloaded circuits and permanent damage to transformers (from melted windings).
Although direct damage to electronics in the style of an electromagnetic pulse (EMP—one of the “side effects” of a nuclear blast) owing to a solar flare is conceivable, it is less likely. “An EMP is a sudden, high-intensity event, whereas a solar storm is a longer-duration, lower-intensity event. Because of these different electrical characteristics, solar storms will typically only generate currents in very long (300 km+) conductors. Hence, technologies that are vulnerable to solar-storm damage include large systems, such as electrical grids, transcontinental pipelines and telephone systems,” said Gallant. “As a result, the electrical and communication systems that data centers depend on are much more likely to be affected by a solar storm than the data center IT infrastructure itself.”
Recent Major Solar Events
The potential for extensive electrical damage from a solar flare is not simply a matter of theory: at least two major events in recent history (i.e., when electricity was in use) illustrate the danger. The most illustrious example occurred in 1859: the so-called Carrington Event reportedly shocked (electrically—but figuratively, too) telegraph operators and even set fire to some of their offices.
A less powerful solar event occurred in 1989, striking Canada and bringing down the Hydro-Quebec power grid. This solar flare, although less extreme than the Carrington Event, illustrated the vulnerability of the grid. Furthermore, even a highly directed flare targeting a narrow region could potentially affect other regions. The Lloyd’s report notes that in 1989, “Voltage oscillations [from the solar flare] caused more tripping of protective equipment, nearly bringing the Northeast Power Coordinating Council (NPCC) and the Mid-Atlantic Area Council (MAAC) down in a cascading collapse…[It] also caused permanent damage to a generator step-up transformer at a nuclear station in New Jersey owned by Public Service Gas & Electric, necessitating its removal from service.”
Factors Determining Vulnerability
The movement of charged particles in magnetic fields is a complicated phenomenon, particularly given all the variables involved in a macroscopic situation like interactions between the Earth and the Sun. Physical factors include ground conductivity (more conductivity means the changing magnetic fields can produce greater currents), proximity to the ocean (sea water is a reasonable conductor) and the “magnetic latitude” (which somewhat follows geometric latitude). Of particular noteworthiness is the role of the oceans, which can increase the intensity of the induced currents during a solar flare event. A look at images of the Earth at night reveals the high concentration of electrical infrastructure relatively near to the coast—meaning greater vulnerability to solar events.
Beyond just physical considerations are infrastructure factors: particularly, the density of transformers in a region. Even a comparatively directed flare can cause tremendous damage if it strikes an area that contains large numbers of transformers. The length of an outage in such cases could conceivably drag on into months as utility companies scramble to repair the damage. Other factors include the transformer design, length of the connected transmission lines and so on.
Effects on Data Centers
Clearly, any event that harms part of the power grid is a potential threat to data centers. Most facilities that prioritize uptime incorporate some infrastructure to deal with electrical contingencies—particularly, UPS systems to maintain a clean power flow and backup generators in case of longer outages. But even these systems are insufficient in the event of outages that extend to weeks or even months. A few mission-critical facilities might have the wherewithal to outlast such an event, but most companies don’t.
The good news is that major solar flares like the Carrington Event are rare; the Earth is a pretty small target for the sun. The bad news is that the risk of geomagnetic storms resulting from solar flares is projected to reach a peak for the current solar cycle in 2015, according to Lloyd’s. There’s not much anyone can do about the sun, but companies can take steps to reasonably protect their data centers from such events.
Many of the precautions for geomagnetic storms are the same as those for other disasters: backup power supplies, a disaster recovery plan and so on. IT equipment left exposed to the grid could easily be damaged or destroyed by power fluctuations. Eric Gallant identifies the following three critical systems to protect the data center:
- “Transient voltage surge suppression (TVSS). A robust TVSS system can greatly reduce the effects of the power surges and spikes that often accompany a solar flare. A well-designed TVSS protection strategy will employ surge suppression at multiple levels, including service entrance switchgear, distribution switchgear and point of application.
- Uninterruptible power supply (UPS). A high-quality, online double-conversion UPS system will also mitigate the effects of harmful electrical transients. In addition, a UPS will provide much needed battery run time that will allow IT systems to be gracefully shut down or standby generators to start in the event of a power outage.
- On-site emergency standby generator. The electrical outages caused by a major solar storm could be long term. It is vital that mission-critical facilities have a generator and plenty of stored fuel on site to provide power generation until utility power can be restored.”
Although intense geomagnetic storms from solar flares/CMEs are rare, they occur frequently enough to treat as a real threat to both data centers and the power grid at large. These events have the peculiar characteristic of only really affecting electrical systems—unlike, say, earthquakes, which damage physical infrastructure. In the worst case, a solar flare could lead to cascading failure of the power grid and, potentially, months-long outages in certain regions. These extended outages pose the greatest danger: in such cases, even the most uptime-conscious companies may be unable to obtain enough fuel to run backup generators for the duration of the outage. But the conceivable isn’t necessarily the likely; some events simply permit no alternative to downtime. The job of data center operators is to prepare for the most likely events in a manner that balances both the threats and the costs.
Image courtesy of NASA Goddard Photo and Video