The VSS+DC uses advanced composite flywheel technology and generates 50 percent more power with the same cost and footprint as the previous generation system. The flywheel power system improves UPS reliability by completely replacing or greatly extending the life of lead-acid batteries commonly used in most UPS configurations. In comparison to such batteries, the VSS+DC improves UPS reliability while eliminating ventilation and costly cooling requirements as well as reducing lifecycle cost and maintenance/replacement needs. By occupying less than 25% of the space of an equivalently sized battery system, the VSS+DC saves valuable floor space in the data center leading to higher computing density. The higher output VSS+DC permits integration with UPS systems rated at 225 kVA or less. Multiple units are easily paralleled without any communications gear to work with higher-capacity UPS systems and still offer exceptional space and conditioning savings over other energy storage products.