The ongoing focus from the public sector and large organizations to improve their ”green” image and reduce their carbon footprint has triggered an ongoing debate about possible alternatives to lead-acid batteries. Flywheels in particular have been a part of that discussion, and there are advantages and disadvantages of each approach. For example, flywheels take up a smaller footprint than VRLA batteries and operate over a wider temperature range, while VRLA batteries provide longer runtime, and more efficient operation.
Of course, the answer to which technology is “greener” depends largely on the definition of green. Is it based on energy efficiency, carbon footprint, recycled raw materials, hazardous materials? Green washing and hype has made it difficult to get to the bottom of this and understand the differences. That’s why we thought it necessary to conduct a lifecycle carbon footprint analysis of flywheels vs. VRLA batteries.
Flywheels vs. Batteries: By The Numbers
Schneider Electric has launched a free online Flywheel vs. Battery Carbon Footprint Calculator that can allow data center operators to compare energy storage for static UPSs. You put in details about your location and capacity requirements, and the tool provides guidance on what you can expect in terms of carbon impact from raw materials, maintenance & delivery, energy to operate, and energy to cool,
The results may come as a surprise to many. In almost all cases, VRLA batteries had a lower overall carbon footprint, primarily because the energy consumed to operate the flywheel over its lifetime is greater than that of the equivalent VRLA battery solution, and the carbon emissions from this energy outweighs any carbon emissions savings in raw materials or cooling. Of course, the tool lets users conduct their own comparison to see for themselves.
This analysis and tool are a good reminder that decisions around energy storage needs to factor in a number of variables. The feature set of a UPS needs to be tailored to businesses on a case-by-case basis, and that includes considerations around carbon footprint. In some scenarios, there may be reasons for batteries and flywheel storage units to coexist. And ultimately, the one thing that’s common across all data centers is the goal to eliminate the risk of downtime.
For years now, experts have been discussing this topic. Continuing to build awareness with tools such as our new carbon calculator will ultimately lead to more innovative solutions to business challenges.