365 Main Outage: Were Flywheels to Blame?

After yesterday’s power outage in San Francisco’s SOMA District shut down data center 365 Main, we weren’t the only ones wondering what sent the operations of the data center screeching to a halt.

(We doubt it was caused by a drunk employee.)

365 Main, the data center that prides itself on year-round uninterrupted service, and provides storage for sites like Yelp (whose reviewers were a bit upset about the outage), Craigslist, CNET, LiveJournal, and Technorati, lost power at 1:49 p.m. Tuesday, after a PG&E transformer failed in a manhole under 560 Mission Street.

So what happened? 365 Main released a statement, which you can read here, claiming their generators failed. But we find ourselves wondering if the eco-friendly flywheels the company uses in its data centers had more to do with the fiasco.

Immediate backup power in data centers is usually provided by lithium-ion systems called UPS, or uninterrupted power supply.

Typically when a power grid fails, UPS batteries will keep the server going for a few minutes until the generator kicks in again. But being eco-friendly, 365 Main does not use UPS batteries. Instead the company opts for flywheel technology, as you can see here in the data center’s spec sheet. Flywheels store kinetic energy that can be released when power backup is needed.

DataCenterKnowledge.com has an informative article that compares the use of flywheels to traditional lithium-ion lead acid backup for uninterrupted power supply. They aren’t widely distributed yet, representing just 6% of the power supply market, according to Frost & Sullivan.

It’s too soon to know what happened yesterday (and like we said, 365 Main released a statement claiming it was the generators), but we called Frost & Sullivan’s analyst Farah Saeed to find out more about what could’ve happened.

Saeed explained that flywheels are used for intermediate power protection, only. “While a flywheel is a highly reliable technology and has fairly high life cycle versus batteries, because it’s all mechanical, the amount of backup power it can provide is restricted. Typically once the power fails, it can run from 30 seconds, at max a minute,” she said.

Rusty Hodge is general manager of SOMAFM and a 365 Main customer. He thinks the repeated power outages might have caused the flywheels to falter.

There were at least five short-term “brownouts” yesterday before the power failed for good—some of them shorter than the time required to trigger the generators. So it makes sense that 365 Main’s flywheel system, already taxed, might not have been at full capacity when the last blackout occurred. – Randy Hodge, SOMAFM

If that’s the case, it looks like flywheel technology might not be an eco-friendly panacea for old school lithium ion lead acid batteries.

But don’t worry. Here are several other UPS alternatives in the pipeline:

  • Nickel-zinc batteries: Nickel-zinc battery developer PowerGenix says it has developed a rechargeable battery “that is as much as 75% lighter, ten times as powerful, 30% smaller and more environmentally friendly than existing nickel-cadmium or nickel-metal hydride batteries,” according to Venture Beat.
  • Fuel Cells: Fuel cell technology generates energy through chemical reactions (if you want to learn how a fuel cell works, check out HowStuffWorks.com’s explaination)—but it is spendy. Public companies such as Plug Power and APC sell fuel cells for power backup starting at around $50,000. Startup Electro Power Systems, based in Torino, Italy, is also developing a fuel cell power-backup system for companies that maintain large data centers. Electro raised $6.7 million in its Series A round back in May.