Why Flywheel Energy Storage?

Active Power's solutions feature flywheels as their central technology, using kinetic energy - energy stored as motion - instead of traditional electrochemical batteries.

Our CleanSource flywheel technology is elegant, efficient and economical, enabling us to create innovative uninterruptible power supplies, DC energy storage systems and modular power and IT solutions that solve power problems for data center, health care, industrial and manufacturing customers around the world.


Flywheel Energy Storage Advantages Lead-Acid Battery Challenges
✓ 20 year operating life ✘ Multiple replacements during UPS life
✓ No degradation with use ✘ Frequent use degrades lifespan
✓ Limited maintenance required ✘ Sensitive to temperature variations
✓ Operating temperature range up to 104°F ✘ Extensive maintenance and monitoring
✓ Compact, enclosed footprint ✘ Expensive safety and health systems
✓ If the flywheel is spinning, power is available ✘ Most common reason for data center outages

40% Lower TCO

Active Power flywheels enable our solutions to have a competitive first cost, reduced installation and setup costs, and significantly reduced operating expensies due to higher energy efficiency and permanent energy storage. All told our solutions will reduce TCO by 40% over the life of your facility.

  • Integrated solution – saves on installation and support infrastructure
  • Highest efficiency – up to 98% energy efficient with full power quality protection
  • Permanent energy storage – no batteries to install, monitor, service, or replace

12x Less Likely to Fail

The integrated flywheel energy storage at the core of our products makes them inherently reliable, delivering predictable, consistent backup power. The normal state of CleanSource Uninterruptible Power Supply is with the flywheel spinning constantly, storing kinetic energy. When called upon during a utility outage, the flywheel is ready to assume the load. By contrast, battery failures are the leading cause of UPS load loss and system downtime, because failures are inherently difficult to predict. A study by Mtechnology, Inc. showed that the CleanSource 750HD UPS is 12 times less likely to fail compared to a traditional UPS with batteries, dramatically improving the overall reliability of your operation.

90% Less Environmental Impact

Our flywheel’s higher energy efficiency and permanent energy storage make Active Power’s solution the green one. Our flywheel will use 90% less carbon during manufacture than traditional batteries. Our system is up to 98% energy efficient, reducing the ongoing carbon emissions and resulting pollution generated from wasting electricity. And because we have permanent energy storage there are no toxic chemical batteries in your facility, nor the need to install, remove, and recycle thousands of pounds of batteries multiple times over the system’s life.

A Great Fit

Flywheels are a better fit for your facility than battery based solutions. Our compact footprint and high ambient operating range (up to 40C) enable you to install it in locations where other systems can’t be – such as directly on your factory floor. And our low maintenance requirements keep you up and running longer and reduce disruption and risk.


5,000+ Flywheels in Service

Active Power has over 5,000 flywheels in service in over 50 countries. Our solutions are trusted by a marquee set of customers across a wide variety of applications and markets.

250+ Million Runtime Hours

Our systems are field proven, with over 250million cumulative hours of power protection for our customers.

$100+ Million in Energy Savings

Our flywheel systems have saved our customers over $100 million since their introduction, primarily thanks to their remarkable energy efficiency.

Active Power's Flywheel Technology

The concept behind flywheels is quite simple: Objects in motion continue in motion unless acted upon by an outside force. Flywheels have been used for more than 5,000 years in textile spindles and potters' wheels and were adapted to machine use during the Industrial Revolution.