Renewable Energy: Flywheels For Backup Power

A typical flywheel system consists of a rotor suspended by bearings inside a vacuum chamber to reduce friction, connected to a combination electric motor and electric generator.
A typical flywheel system consists of a rotor suspended by bearings inside a vacuum chamber to reduce friction, connected to a combination electric motor and electric generator. (Image: VYCON.)

By Frank DeLattre
From the November/December 2014 issue

Vital to the mission of Texas Scottish Rite Hospital for Children in Dallas, TX is reliable operation of advanced MRI technology as well as other high-tech medical instrumentation. Founded in 1921, this non-profit hospital conducts leading-edge research and sponsors teaching programs, instructing doctors from around the globe. The 900,000 square foot hospital operates from a single campus, but provides professional orthopaedic services to Children’s Medical Center of Dallas.

Much of the hospital’s advanced technology is located in its imaging suite, officially known as the Seay/Pickens MRI Center. The hospital also contains CT, digital radiography, and ultrasound rooms. Among the state-of-the-art medical devices are a Computerized Tomography (CT) scanning system and a Magnetic Resonance Imager (MRI). To benefit patients, this sensitive instrumentation must function perfectly 365 days a year.

In fact, hospital administration insists that the radiology technology—a Signa HDxt 1.5T MRI along with the 64-slice Philips Brilliance CT—run seamlessly throughout the day and night. However, when power outages occur due to storms or other power grid related problems, such disruptions can severely impact patients, delaying their diagnoses and subsequent treatments. This disruption can result in rescheduling of imaging appointments, upsetting the equilibrium of the medical facility, and impacting its revenues.

Twice in the hospital’s history, its imaging suite was completely shut down because of power outages beyond the staff’s control. Currently, the facility is prepared for power outages caused by natural or man-made disasters of any type. The imaging suite there contains a pair of 300kW kinetic energy storage flywheels for emergency backup power. The kinetic energy storage flywheel functions similar to an active mechanical battery that supplies kinetic energy by rotating a mass around an axis. Electrical input rotates the flywheel rotor to its capacity, and a backup electrical charge keeps it spinning continually until it needs to discharge the accumulated kinetic energy.

The volume of kinetic energy accessible and its length of time are relational to its mass and the square of its rotational speed. For flywheels, increasing mass twofold also increases the storage of energy twofold. However, increasing the speed of revolution increases the capacity of energy by a factor of four. In other words, a substantial volume of energy can be stored into a fairly limited space. When a power disruption occurs, the flywheel can provide standby power quickly, delivering energy to the connected load precisely as it would do with a battery string.

The flywheels installed at Texas Scottish Rite provide a smooth, reliable, and environmentally friendly energy storage alternative to uninterruptible power supply (UPS) systems that use lead-acid batteries. These batteries degrade every time they are cycled, take up valuable space, and can require expensive cooling systems. Flywheels can be used in conjunction with these batteries for a facility’s backup power system.


Currently, Texas Scottish Rite is increasing office space for its orthopedic team. Adds Don Katz, vice president of facilities and process design there: “We take pride in being good stewards of our hospital funding to make the best use of space available, always placing the greatest emphasis on meeting our patient care needs. In fact, the phrase, ‘creativity over capital’ describes our philosophy well. With that said, we have recently embarked on a Facility Master Plan to determine the most strategic approach to meeting our growth requirements as well as ensuring the use of our existing space is optimal from a patient and workflow standpoint.”

Promoted to president in 2009, DeLattre joined VYCON in 2007 to take the helm of the company’s UPS and power quality division. Located in Cerritos, CA, VYCON is a manufacturer of flywheel energy storage systems. Having spent more than 20 years in power quality and related industries, DeLattre holds a bachelor of science from San Diego State and an MBA from West Coast University.