There is currently a poorly met need for reliable no-maintenance UPS (Uninterruptible Power Supplies), for critical manufacturing, hospitals, cell phone repeater sites, computing centers, datacom,  telecom, and intranet/internet servers and routers.  The Electric Power Research Institute estimates that central utility grid power outages, sags, and spikes, cause losses amounting to $100 billion yearly.  These losses are rising with increased dependence on quality power.  Also, chemical battery power storage and fuel-burning generators can't provide practical UPS in remote locations, due to their maintenance and fuel logistics needs.  With virtually no losses, unlimited service life without need for maintenance, and lower annual cost than existing options,  we expect RPM's systems can,  in 10 years,  grow a $10 billion yearly US market for UPS to $20 billion.

Solar power for a space-craft, from photovoltaic panels, is very practical -- but not if chemical batteries are needed to supply power during extended periods when sunlight is blocked (e.g., by the earth):  Satellite battery maintenance and replacement is not feasible, and their poor reliability is inconsistent with mission-critical applications.  Also, long-term space-craft attitude control is limited by existing jet thrustors.   RPM's power storage/regeneration systems can power low-earth-orbit and geostationary communications satellites during their dark hours, re-energized by photovoltaic panels during sunlight hours.  Virtually unlimited service life with no maintenance, ultra-high efficiency, zero idling losses, and ultra-high reliability, are major advantages RPM's systems have for space vehicles, over all other UPS. And besides power, RPM's systems can provide inertial pitch/roll/yaw control.  That would eliminate the need for gyros and jet thrustors, and most importantly the fuel consumed by the thrustors.

Cell phone and com tower UPS, remote site UPS, and satellite UPS + pitch/roll/yaw control, will be RPM's most viable near-term market, during production ramp-up and expected product cost reductions.

Ultimately, RPM's flywheel batteries can enable a global $200 billion new building-integral solar/wind power industry, and can even enable dual-mode high-performance electric highway vehicles.  These clean, sustainable technologies will afford profound environmental benefits.

Conventional UPS is mainly a combination of high-maintenance diesel-generators and lead-acid batteries.  Other flywheel storage systems offer only short-term (most "tens of seconds") ride-through power, during utility line outages; and while the utility or on-site generator supplies power,  they constantly consume typically kilowatts while idling. That's over 1000x more losses than RPM's flywheel power storage system; which runs far cooler, will have far longer service life, negligible self-discharge, far higher reliability, far lower life-cycle cost, no wear-out, and will not need maintenance.

For on-site generated solar or wind power, that is available on demand, or distributed power storage for load-leveling, other available on-site options require tons of  lead-acid  batteries, that have troublesome limits on numbers of charge/discharge cycles, plus service, replacement, reliability, safety, pollution, siting, and toxic materials disposal problems.  In such applications, requiring daily or even more frequent charge/discharge cycles, annualized life-cycle cost is higher than RPM's flywheel battery.

Other flywheel energy storage systems have been developed for different purposes, and don't meet needs for practical carefree UPS -- and certainly not for on-site solar/wind power systems (which we view as our ultimate market)  -- mainly because their idling losses and resulting failure modes are intolerable.

RPM's flywheel power storage system can provide on-site (underground flywheel for most urban installations) long-term (days) uninterruptible power. It can store energy for years, without significant self-discharge.  It will afford safe, care-free, clean, quiet, no-maintenance, environment-friendly UPS and on-site power storage with virtually no cycling limits, at lower life-cycle cost, than all other options (including fuel-burning generators). Weight of our total flywheel power storage system is now about 20% that of lead-acid batteries; future fiber-composite materials may reduce its weight to 10%.

What gives RPM's flywheel electric power storage system such remarkable competitive advantages, and performance not available from any other:

• Ultra-efficient motor/generator (m/g) with essentially no idling loss. Its permanent-magnet rotor is integral with a magnetic bearing rotor and flywheel rim, that spin together in a vacuum enclosure, without mechanical contact to stationary parts.  Its patented configuration incurs no hysteresis losses;  its windings block and buck eddy current.
• Magnetic bearings with practically zero-power axial and radial electronic servos; with a levitated rotor having axial and radial stability and stiffness, spin with no physical contact, and no hysteresis or eddy loss, for practically no idling loss.
• Rolling contact touchdown bearings, used only during transit to installation site and emergency backup, don't depend on lubrication (which is not practical to maintain in vacuum).
• Concentric cylinder carbon fiber composite flywheel rim, for low weight, safe, and lower cost bearings.
• Power controller that interfaces m/g to dc power conduit, has PWM (Pulse-Width-Modulated) sinusoidal current control, responsive to dc conduit voltage, rotor feedback, rotor vibration (prevents over-speed, full-energy explosion; monitors reserve energy, etc.). Controller includes integrated safety, bearing servo electronics and m/g control; has  LCD (minimal power Liquid-Crystal-Display) for monitoring; runs on under 2-watts power (including bearing, m/g, and windage losses). Parallel systems can accommodate more diverse applications and greatly enhance reliability.
• Light-weight thin-wall vacuum enclosure for flywheel and other parts it contains. Unlimited life with no maintenance facilitate housing it in an underground site that can absorb a possible nearly adiabatic explosive burst.

This is a zero-maintenance design, that makes safe underground installation practical.

Due mainly to its exclusive zero idling losses, the system uses under 2-watts to maintain full energy, and all its on-line monitoring, safety, and display functions.

Unique safety features include:  Electronics, that  initiate power-down on sensing abnormal magnetic bearing servo activity;  concentric rims, that prevent total flywheel disintegration;  and underground siting, that can absorb rapid energy discharge, which prevents damage outside the flywheel site, from possible flywheel disintegration.  It uses a standard reinforced concrete slab floor, and flush bolt-down steel cover enclosing the flywheel site, that protect building occupants from possible blast and explosion fragments.

All of  these proprietary features are obtained at lower life-cycle cost than any other power storage device, mainly due to thorough integrated system design expressly dedicated to stationary on-site applications.

Right: Block diagram of electrical system of a building, with RPM flywheel battery and multiple power sources.

RPM created the only flywheel UPS that will accommodate on-site solar and wind power, utility-line-powered UPS (switchgear at U.P. for utility power,  P.F. during utility power failure outage), and any combination of power inputs.

It can have adequate power generation and storage capability, plus discretionary loads, so that it does not require utilities to buy excess power generated on-site.  Also, it does not subject utility lines to hazardous "live"  loads, which have killed workers performing otherwise routine line repairs.

The PWM regulator interface, to solar tiles and windmill generators, maximizes their energy yields and prevents dc line over-voltage when the flywheel reaches maximum energy capacity.

At first glance, except for reducing 60-Hz inverter cost, it may seem that including dc power outlets does not make sense, because it requires additional wiring and another type of socket, to prevent users from plugging in electric appliances that could be damaged by dc. But that rationale neglects these facts:

Most consumer electronics could be produced 10-60% smaller and lighter, 10-40% lower cost, and even more reliable, if designed for dc. It would eliminate need for rectified 60-Hz hold-up capacitors in all, 60-Hz power transformers and rectifiers in many.  That's ample incentive for their producers to make the straightforward changes needed within a year, for their products to work from dc power outlets.

Electric ovens, cook-tops, toasters, and incandescent lights can use ac and dc interchangeably.

Power tools like drills, saws, etc. have universal motors. They are more efficient with dc, because ac causes more core loss.

Most induction motors; for fans, blowers, refrigerators, washers, and dryers, run at less than 50% efficiency on single-phase 60-Hz power.  Brushless dc motors that run at more than 90% efficiency, and are smaller and lighter, could replace them.

Conventional 60-Hz inductive ballast, for fluorescent lights, could be replaced with smaller instant-starting electronic ballast.  SCR light dimmers and speed control can be replaced with numerous types of  PWM controls that run on dc power.

Clearly, there are enough advantages for most dc appliances, to replace ac within a 1-year transition period.

Left: Underground installation, made practical by our zero-maintenance design. It can absorb a maximum fast-release energy discharge (exploding flywheel) with minimal pressure and temperature rise.

It uses a standard reinforced concrete slab floor (except for the flywheel siting installation) of a garage or storage area for a safety barrier between the flywheel and other parts of  the building.

The backfill is permeable, and preferably filled with energy-absorbing material, to absorb energy over a volume far larger than the flywheel enclosure.

Besides its safety advantages, this underground flywheel siting design does not take up valuable space. This feature further reduces overall cost of  the building UPS. Existing UPS batteries, housed on multiple-level shelves, and fuel-powered generators, need a ventilated off-limits area protected from weather, that is a major additional site expense.

Examples of clean, cost-competitive, convenient, care-free, renewable on-site power that RPM's flywheel electric power storage system can ultimately enable, to meet vast global power needs ...

Right: Proposed remote UPS application, integrated with photovoltaic solar tiles and windmill power generator.

By enabling clean renewable energy use, it can help meet vast global power needs, besides current need in remote homesites, military posts, scientific field stations, etc. These remote applications are expected to be a substantial part of  RPM's early markets.

PV (photo-voltaic) solar panels and windmills are increasingly used to provide power for remote buildings. Lead-acid batteries are currently the only real available option for power storage.  They are not widely acceptable in millions of  US buildings that need UPS (e.g., medical, dental, critical manufacturing, banks, etc.)  due to high maintenance, replacement, and life-cycle cost, plus housing and toxic waste disposal problems.

Right: Proposed urban building design, suitable for mini-malls, offices, manufacturing and commercial facilities; with solar tiles generating power, providing translucent skylight and window areas, and funneling wind to increase windmill power.

Building-integral PV panels are the basis for a very high growth industry. But windmills are rarely integrated with them.

Combining solar and wind power can provide higher energy yields, with lower peak-to-average power ratio; and thus lower power electronics cost. It will encourage innovative new architecture, of cost-effective and attractive buildings, with stand-alone power capability.

UPS and load leveling (with lower off-peak utility rates) are afforded to buildings connected to utility power lines.  Benefits from UPS depend upon criticality of on-site power.  Off-peak rate savings alone could result in typical payback periods of  10 to 20 years for RPM's flywheel battery.

Most importantly, buildings like this could enable profound environmental and energy conservation benefits.

Left: Proposed urban or remote building design,  with solar tiles providing roofing, skylights, windows, and exterior walls.

This is a cost-competitive,  functional, attractive,  integrated-power building, with important energy and environmental benefits.

The building provides high elevation mounting, without incurring the cost of towers, for the integrated windmills,  and funnels wind through them,  to increase power generated by 10x or more.

Through-flow (possibly hemispheric shape) small-mesh (.5"x.5") grills on each side of the windmills provide a shield around them,  to protect people and other parts of the building from harm of possible blade disintegration;  eliminate bird kill; and shield blades from sun damage (particularly ultra-violet on fiber-composite blades).  A vertical-axis rotatable "ring mount" can support the turbine and its bearings.

It should result in far less cyclic blade and stem stress, and "swooshing sound" compared to typical towers.

Examples of attractive homes by pioneering architects, with handsome solar tile roofing and lead-acid battery power storage. RPM's Flywheel Battery would be ideal for, and encourage future projects like these, and enable far greater use of  clean, renewable, cost-competitive, ubiquitous, environmentally compatible energy sources ...

Global markets for PV panels is now over $1 billion yearly,  and growing about 50% yearly.  It would grow much faster with RPM's on-site flywheel battery,  providing carefree,  lower total life-cycle cost power storage.

RPM Flywheel Battery Comparison with Others (we don't run with the pack)

RPM Business Plan Abstract (who we are, what we've done, what we plan)

Flywheel energy storage tutorial (review of basic flywheel physics & applications)

On-site Solar and Wind Power Tutorial and Examples

Building-integral Solar and Wind Power Benefit/Cost Estimates

Electric Vehicles with In-transit Power from Highways: Graphic Analysis

Links to flywheel batteries, solar and wind power, dual-mode EVs, and a plan to achieve them

Urban EV with Onboard Batteries, Charger, PV, Regenerative Motor, Pedals

RPM's UPS+CMG for satellite power and angular orientation: Illustrated analysis

Future environmentally responsible and sustainable electric power options

We hope you share our vision.  For more examples of  projects by pioneering architects and builders, and
renewable power research programs, visit these links:

Featured Solar Building Construction Projects (RPM hopes to play a pivotal future role)

Solar Design Associates (architectural firm designing building-integral solar power buildings)

Renewable Energy Projects at NREL (has links to NASA and contractor sites)

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