All UPS energy storage options have pros and cons. Here’s what some independent experts have to say about these options.
"When it comes to UPS energy storage, there's no one-size-fits-all," explains Scott Offermann, managing director, critical environments group at Cushman & Wakefield. "We recommend all three solutions to our clients, and we've seen different companies use different solutions successfully, whether it’s lead-acid, lithium, or flywheels. The solution you choose depends on the needs of your business and your mission-critical facility."
"If a company has used lead-acid batteries in the past, they usually prefer to stick with the solution they know," adds Rajan Battish, vice president – mission critical with CallistonRTKL. "Hyper-scale and colocation data centers are risk averse, and reluctant to try out new technologies. Also, data center construction is driven by scheduling, and introducing a new technology may slow down the completion of a facility.
"However, lithium batteries might be a good solution if you have weight constraints — for example, if you're installing a UPS in a mission-critical environment on the second floor of an office building. As for flywheels, we've seen them used successfully in more specialized applications, such as larger Tier 1 or Tier 2 facilities, or facilities where transfer schemes and backup systems are not as critical."
What UPS System Manufacturers Say
"The key factors to consider when selecting an energy storage system are expected lifetime, cost, and how much runtime you want from your UPS," says Jeff Kessen, vice president of global energy storage at Vertiv. "Most of the market is conditioned to accept the value and limits of lead-acid batteries. But lithium batteries are rising, because companies believe they can monetize the batteries' extra life and [total cost of ownership] savings.
"Flywheels are best suited for UPS applications with very short runtimes. For operators who feel confident in their UPS's ability to quickly bring up a backup generator during the switchover, flywheels can be an acceptable solution. But most data center operators still require an energy storage solution with a runtime of 5 to 10 minutes."
"If you're thinking of switching from lead-acid to lithium batteries, the best time to do it is when you're buying new UPS appliances," adds Susan Poe, a regional director with Schneider Electric's home and business networks group. "If you decide to retrofit an existing UPS with lithium batteries, it's best to contact your UPS manufacturer. You may need to upgrade the UPS software and firmware, and integrate the battery management system with your UPS, to make lithium batteries compatible.
"When buying a new energy storage solution, it's very important to look at the company providing that solution. You need to make sure they are capable of properly sourcing, designing, and manufacturing a solution that is efficient and cost-effective for the needs of your UPS storage system and your mission-critical environment."
Robert S. Lindsay is a technical and marketing writer, based in the Seattle area. He writes for the data center and critical infrastructure industries, and also for cloud, IoT, mobile, and telecom technology companies. He can be reached at firstname.lastname@example.org.
Comparing Uninterruptible Power Supply (UPS) Energy Storage Options
UPS Energy Storage Option 1: Lead-Acid Batteries
UPS Energy Storage Option 2: Lithium-Ion Batteries
UPS Energy Storage Option 3: Nickel-Zinc Batteries
UPS Energy Storage Option 4: Flywheels
Which UPS Energy Storage System Should FMs Use?