As businesses continue to change and adapt to the digital economy, the management of today’s data centers and the protection of their hardware is at the mercy of power reliability. The result of any kind of power event, whether it be a fluctuation, a voltage reduction or a full blackout, could be disastrous, with the potential for serious cost implications including a halt in mission-critical operations. The result is lost revenues and customer goodwill. The costs of unplanned downtime are very high. For example, according to the U.S. Department of Energy, an airline reservation center loses about $90,000 per hour, and a credit-card operations center stands to lose more than $2.5 million per hour during power outages (Distributed Energy Resources Program and Strategic Plan, 2001). As one can imagine, the costs are even higher today.
For IT organizations, the pursuit of operational excellence has expanded to a new level of reliability, incorporating new methods of safeguarding systems that turn the traditional approach on its head. “Old school” power protection has proven to be a disappointment in a number of ways.
Tried and Tested… but True?
In securing data center efficiency, IT managers must take a careful look at the power infrastructure. Through the years, to ensure that critical processes ran without interruption, large-scale uninterruptible power supplies (UPSs) were used to continually take the frequent fluctuations and disturbances of utility power and condition it, delivering clean energy to critical systems. In the era of the mainframe data center, a UPS was sized with enough batteries to allow an orderly shutdown of the centrally controlled computers in case the outage was long term or if the backup genset failed to come online. In recent history, IT managers were content with 15 minutes of battery backup, comfortable in the assumption that batteries would be effective in safeguarding large amounts of data and key hardware. As distributed computing became popular with LANs and WANs, orderly shutdowns were more difficult to coordinate and required specialized software.
Through the years, lead-acid battery-based UPSs have proven to be expensively unreliable. One bad cell in a string of 40 batteries can result in failure to protect servers against a power outage or under- voltage condition. Batteries also require an excessive amount of testing, monitoring and maintenance to prevent such occurrences—exhausting procedures that bog down IT activities. Data from major UPS companies confirms that 70 percent of the service calls made on a failed UPS system were a result of a battery problem. Forty percent of cases involving a condition where power was lost to a critical load were a result of a failed battery system. What’s more, UPS batteries contain toxic chemicals and require very stringent methods of disposal. From a green viewpoint, this characteristic doesn’t sit well with IT managers looking to institute environmentally friendly initiatives in the data center.
High-availability data centers are not simply seeking 10 to 30 minutes of backup. They require continuous power to ensure the protection of large amounts of data, not to mention the hardware supporting it. As such, these data centers are designed to be redundant, incorporating a power structure that is supported by multiple UPSs and generators. At this level, IT managers know that their operations require much more than 10 to15 minutes of battery backup and are relying on multiple generators to get the job done. Thus, IT managers must evaluate many considerations when it comes to increasing energy efficiencies while ensuring the success of operations. The challenge becomes how to implement more-energy-efficient technologies without disrupting high-nines availability and while achieving a low total cost of ownership (TCO). This challenge becomes even more difficult when looking at the power-protection infrastructure.
Anatomy of a Flywheel
The flywheel clean-energy-storage system is an environmentally friendly alternative to lead-acid batteries. Flywheels have been used since the Bronze Age as a way to store kinetic energy. Today, with new high-speed-motor technology and state-of-the-art electronics, highly efficient flywheel systems provide consistent, dependable energy for a variety of critical applications. The flywheel works like a dynamic (mechanical) battery that stores energy kinetically by spinning a mass around an axis. Electrical input spins the flywheel rotor up to speed, and a standby charge keeps it spinning 24/7 until called on to release the stored energy. The amount of energy available and its duration is proportional to its mass and the square of its revolution speed. For flywheels, doubling the mass doubles energy capacity, but doubling rotational speed quadruples energy capacity.
During a power interruption, the flywheel provides backup power seamlessly and instantaneously (Figure 1)—good news for IT managers who are finding the reliability of battery-based UPSs questionable. When the flywheel is used alone (without batteries) the system will provide instant power to the connected load as it does with batteries. If a power event lasts longer than 10 or 15 seconds, the flywheel will seamlessly move to the data center’s engine generator. For longer run times, additional flywheels can easily be integrated. EPRI’s research shows that 80 percent of all utility power anomalies/disturbances last less than 2 seconds and 98 percent last less than 10 seconds. In the real world, the flywheel energy-storage system has plenty of time to gracefully hand off to the facility’s generator.
From 40kVA to megawatts, flywheel systems (Figure 2) are increasingly being used to assure the highest level of power quality and reliability in a diverse range of applications. The flexibility of these systems allows a variety of configurations that can be custom tailored to achieve the exact level of power protection required by the end user according to the budget, space available and environmental configurations. In any of these scenarios, IT managers can garner a number of benefits, including the following:
- High power density, small footprint
- Parallel capability that allows for future expansion
- Low total cost of ownership (TCO)
- 20-year useful life
- High efficiency (99%)
- Low maintenance and simple installation
- Seismic rating options (shaker-table tested)
- Wide operating-temperature tolerance
- Fast recharge (under 150 seconds)
- No special facilities requirements
- N+1 redundancy options
- Quiet operation
Flywheel implementations comply with the highest international standards for performance and safety, including those from UL, CUL and CE. Additionally, they offer a cost-effective and environmentally friendly alternative to traditional lead-acid batteries, delivering higher performance and reliability. Given the need to replace batteries regularly, switching to a flywheel system makes economic sense for users looking to safeguard large quantities of data.
While the initial purchase cost of lead-acid batteries is low, frequent maintenance and replacement costs, expensive cooling requirements, fire hazards, spill containment, large space demands and disposal/environmental issues have IT personnel looking at alternatives—specifically, alternatives that offer strained budgets significant energy savings. Flywheels used with UPS systems (instead of batteries) provide reliable mission-critical protection against transients, harmonics, voltage sags, spikes and outages. For those who can’t let go of their dependence on batteries, the flywheel system can work alongside batteries, providing a first line of defense against costly power problems—essentially taking the hits to preserve the life of the UPS batteries.
One measure of a data center's power efficiency is its power usage effectiveness (PUE), which is the ratio of total power consumed by the facility for IT, cooling, lighting and so on divided by the power consumed by IT gear. According to the Uptime Institute, the typical data center has an average PUE of 2.5. This number can go higher when the facility must expend more energy to cool battery-based UPSs. If not properly cooled, batteries will degrade, quickly putting the power-protection infrastructure at risk. Conversely, flywheels do not need separate cooling.
Getting the Green Light
As IT managers look to implement green measures to maximize data center efficiency, addressing the power infrastructure is a logical and lucrative first step. The demand for more energy won’t go away, nor will budget concerns. Balancing high-nines reliability while reducing energy consumption is an ongoing goal, and flywheels are one green solution that makes environmental and financial sense.
Leading article image courtesy of Acoustic Dimensions
About the Author
Promoted to President in 2009, Frank DeLattre joined Vycon in 2007 to take the helm of the company’s Uninterrupted Power Supply (UPS) and Power Quality division of the company. Frank brings a wealth of knowledge and technical sales experience in both domestic and international markets, having spent more than 20 years in power quality and related industries.
Frank began his career at Topaz Electronics, a manufacturer of uninterruptible power supplies. In 1990, he joined Deltec Electronics Inc., also a manufacturer of UPS systems, as Vice President of International Sales. In 1999, he joined Active Power, a manufacturer of flywheel energy-storage systems. Frank was appointed Vice President of Sales for Cherokee International, a leading manufacturer of AC-DC custom power supplies, in 2003. Before joining Vycon, Frank served as Senior Vice President of Sales, Marketing and Service at Pentadyne, a Los Angeles-based flywheel company.
Frank holds an MBA from San Diego University and a BS from West Coast University.