CleanSource® DC

CleanSource DC is as a battery-free energy storage alternative for your mission critical UPS. CleanSource DC supplements or replaces battery strings in your UPS system, improving reliability while driving down lifecycle cost.


Total Cost of OwnershipPower Density
Predictable, visible, monitored power
20 year life and unlimited cycling = no battery replacements
Less than 25% of the space requirements of battery systems


Kinetic Energy

CleanSource DC uses Active Power’s elegant CleanSource flywheel technology to store energy for use with your Uninterruptible Power Supply.Flywheel systems store kinetic energy - energy produced by motion - by constantly spinning a compact rotor in a low-friction environment. When short-term backup power is required because utility power fluctuates or is lost, the inertia allows the rotor to continue spinning and the resulting kinetic energy is converted to electricity.

  • 4.4" high; 25.5" in diameter; 600 lbs
  • Flywheel constantly spins (~ 7,700 rpm) in a vacuum
  • Each flywheel provides 250 kW for ~15 seconds


Data Center

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Health Care

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Industrial & Manufacturing

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CleanSource 250DC

250 kW DC power (single cabinet, single flywheel)

CleanSource 500DC
500 kW DC power (single cabinet, dual flywheel)

Paralleling Capability
Up to 4 systems / 2,000 kW for redundancy or capacity


Battery Replacement

When used as sole energy storage for a double conversion UPS, CleanSource DC provides bridging power to continuous backup power source

Lower cost of ownership than batteries over product life

Superior reliability / predictable power

Infinite cycles without degradation of performance or energy delivered

Battery Hardening

When used in combination with batteries, CleanSource DC improves total cost of ownership and reliability of the system.

Flywheel serves as primary energy storage for frequent and short power disturbances

Battery serves as secondary energy storage for extended power outages

Two sources improve system reliability

Flywheel improves lifespan of batteries – addresses 98% of power issues lasting less than 10 seconds