Power Ring Energy Storage Flywheel

Through a continuing $250,000 Department of Energy Inventions & Innovations grant and recently completed grants from the National Science Foundation, US Navy and the New York State Energy R&D Authority (NYSERDA), LaunchPoint is pursuing research and development of a magnetically-levitated energy storage flywheel dubbed “The Power Ring”. The project could provide some much-needed relief for the presently overburdened U.S. power grid system.

Electricity is critical to our economy, but increasing demand for growth has saturated the power grid, causing instability and blackouts. The economic penalty due to lost productivity in the U.S. exceeds $100 billion per year. Opposition to new transmission lines and power plants, environmental restrictions, and an expected $100 billion grid upgrade cost have slowed system improvements. Flywheel electricity storage could provide a more economical, environmentally-benign alternative. It could also cut economic losses if units were scaled up in a cost effective manner to much larger power and capacity than the present maximum of a few hundred kW, and a few kWh per flywheel.

LaunchPoint’s goal for the Power Ring has been to design, construct, and demonstrate a small-scale third generation electricity storage flywheel using a revolutionary architecture scalable to megawatt-hours per unit. We have currently completed design and construction of a 3 kWh flywheel motor and are assembling the rim and housing units, estimating the completion of a final small scale prototype for testing in May 2007.

A flywheel is a device used to store massive amounts of energy. It works by spinning a large ring mass, the momentum of which can be used to provide auxiliary power to a system's load. Though just out of the concept phase, the Power Ring is a magnetically-levitated version of the standard flywheel. It is more cost-effective, provides more power and has more features than current flywheels.

First-generation flywheels are built from bulk materials such as steel and provide inertia to smooth the motion of mechanical devices such as engines. They can be scaled up to tens of tons or more, but have relatively low energy storage density.

Second-generation flywheels use similar designs but are fabricated with composite materials such as carbon fiber and epoxy. They are capable of much higher energy storage density but cannot economically be built larger than a few kWh of storage capacity due to structural and stability limitations.

LaunchPoint is developing a third-generation flywheel — the “Power Ring” — with energy densities as high as or higher than second generation flywheels by using a totally new architecture, scalable to enormous sizes. Electricity storage capacities exceeding 5 megawatt-hours per unit appear both technically feasible and economically attractive. The design uses a new class of magnetic bearing – a radial gap “shear-force levitator” – that LaunchPoint discovered and patented, and a thin-walled composite hoop rotating at high speed to store kinetic energy.

So where might the Power Ring be used? Hospitals have long carried on-site emergency power, so that vital systems could remain operational even during a power blackout. Power Ring technology could become a low-cost replacement for these existing battery-based UPS systems. Power Ring technology could also be used as a buffer stage in a power system in areas prone to brownouts or in situations where excellent power quality is required.

Another use for the flywheel would be as a buffer between different sections of the nation's power grid. Currently, the utility grid is one giant system that must be perfectly in-phase for it to distribute power efficiently. As a result, a problem in one area of the power grid can have a crippling effect on other areas, as the problem ripples through the system.

If the Power Ring were installed as an electrical buffer between grid sections, the grid would be stabilized and could be run closer to peak levels. Additionally, the following features inherent to the Power Ring would give even more stability to the power grid:

• Peak shaving
• Frequency regulation
• Arbitrage control

A next-generation flywheel such as the Power Ring would:

• Cut costs
• Reduce fuel consumption
• Eliminate emissions
• Reduce the need for new power plants

Other uses for the Power Ring include: 

• Grid frequency regulation
• Hybrid diesel-electric locomotives
• Grid power quality improvement
• Large facility power quality
• Support for renewable energy
• Railroad power smoothing
• Large-scale spinning reserves
• Energy management
• Distribution and transmission deferral
• Demand reduction
• Time-of-use rates

Read the conference paper from Maglev 2006: Third Generation Flywheels For High Power Electricity Storage.