Industry Insights

CI: Data Center Trend #2: A Backup Technology Better than Batteries?

Thursday, August 18, 2016 | by Justin Baillargeon

The second data center trend we will be focusing on as part of our Connected Infrastructure: Data Center Trends series is a technology that is challenging traditional UPS designs. The technology I’m referring to is called the flywheel. It’s a technology that has been around for ages, found in automobiles and sewing machines and started showing up in data centers in the 1990s as a means to store energy.

Flywheel UPS systems store energy as kinetic energy in a spinning disc as opposed to storing energy into variable-regulated lead acid batteries which rely on a chemical process. The flywheel becomes the energy storage medium, spinning a steel disc at a very high rate within a vacuum sealed chamber. When the power is interrupted, the Flywheel can convert the kinetic energy of the disc spinning into usable energy for the facility’s equipment. This allows the system to achieve a 98-99% energy efficiency when traditional battery-based systems experience, on average, a 93% energy efficiency rate.

In addition to more efficiently storing energy, a flywheel UPS can realize a space savings as well, with up to 50% less space being required than battery-based systems due to the elimination of large battery banks. Flywheels also have the advantage of having a wider operating temperature range of 0 – 104°F whereas lead-acid battery systems have a recommended operating temperature of 77°F.

There’s even more efficiency to be had when it comes to maintenance of the system. Flywheels require maintenance only once a year and are projected to last 20 years before replacements might be necessary. The lead-acid battery systems often require maintenance 2-4 times per year and battery replacement about every 5 years. The reduction in maintenance time alone should be enough for facilities to adopt this system, at least that’s what seems to be the case.

However not everything is greener on the other side. With the increased efficiency comes a tradeoff that has made the adoption of flywheel-based systems difficult. Traditional UPS systems have a runtime average of 15 minutes. Flywheel UPS systems on the other hand only provide backup power for 15 seconds. This staggering difference alone provides enough hesitation that the solution can be solely excluded as an option. The 15 seconds that it provides though is enough for most backup generators to kick on and provide power, however that still seems like a very limited and small timeframe to ensure everything is back up and running properly. A battery-based system not only provides 15 more minutes of power but also that much more peace of mind if the generators aren’t able to kick on fast enough.

Even with the limited runtime provided by a flywheel, many organizations have adopted them over the years, even large companies such as Verizon Terremark. Would you consider using a Flywheel UPS system in place of batteries in the future or are waiting out on the potential that Li-Ion may bring. Let us know by tweeting at us @Ortronics .