High performance Energy Storage 7/4/2007

Science Daily — North Carolina State University physicists have recently deduced a way to improve high-energy-density capacitors so that they can store up to seven times as much energy per unit volume than the common capacitor. High performance capacitors would enable hybrid and electric cars with much greater acceleration, better and faster steering of rockets and spacecraft, better regeneration of electricity when using brakes in electric cars, and improved lasers, among many other electrical applications.

A capacitor is an energy storage device. Electrical energy is stored by a difference in charge between two metal surfaces. Unlike a battery, capacitors are designed to release their energy very quickly. They are used in electric power systems, hybrid cars, and all kinds of electronics.

The amount of energy that a capacitor can store depends on the insulating material in between the metal surfaces, called a dielectric. A polymer called PVDF has interested physicists as a possible high-performance dielectric. It exists in two forms, polarized or unpolarized. In either case, its structure is mostly frozen-in and changes only slightly when a capacitor is charged up. Mixing a second polymer called CTFE with PVDF results in a material with regions that can change their structure, enabling it to store and release unprecedented amounts of energy.

The team, led by Vivek Ranjan, concluded that a more ordered arrangement of the material inside the capacitor could further increase the energy storage of new high-performance capacitors, which already store energy four times more densely than capacitors used in industry. Their predictions of higher energy density capacitors are encouraging, but have yet to be experimentally tested.

Alternative Energy Storage Methods

		A brief diversion Several non chemical energy storage techniques have been developed over the years, mostly for very high power applications and while all of them have been used in practical systems, apart from capacitors, there has been slow take up of the ideas up to now. Some examples are given here.

Capacitors - The Electrostatic Battery

The use of capacitors for storing electrical energy predates the invention of the battery. Eighteenth century experimenters used Leyden jars as the source of their electrical power.

Capacitors store their energy in an electrostatic field rather than in chemical form. They consist of two electrodes (plates) of opposite polarity separated by an electrolyte. The capacitor is charged by applying a voltage across the terminals which causes charge to migrate to the surface of the electrode of opposite polarity.

The energy stored is related to the charge at each interface, q (Coulombs) , and potential difference, V (Volts), between the electrodes. The energy, E (Joules), stored in a capacitor with capacitance C (Farads) is given by the following formula.

E = ½ q V = ½ CV²

See What can a Joule do? for an example.

Since capacitors store charge only on the surface of the electrode , rather than within the entire electrode, they tend to have lower energy storage capability and lower energy densities. The charge/discharge reaction is not limited by ionic conduction into the electrode bulk, so capacitors can be run at high rates and provide very high specific powers but only for a very short period. Typical numbers for capacitors and batteries are given below:

	Capacitor / Battery Comparison
Device Energy density Wh/L Power density W/L Cycle life Cycles Discharge time Seconds Batteries 50-250 150 1 - 103 > 1000 Capacitors 0.05 - 5 105 - 108 105 - 106 <1

See also examples of the relative energy storage capacities of capacitors and batteries in the section on Short Circuits.

Since there is no chemical reactions are involved, the charge/discharge reactions can typically be cycled many more times than batteries (10⁸ cycles per device have been achieved). For the same reason, capacitors don't require any special charging circuits and cells can be designed to accept very high voltages, although for very high capacities the working voltage is limited to a few volts.

Supercapacitors are simply capacitors employing plates with extremely high surface areas providing a high storage capacity. Maximizing the surface area of the electrodes within the available space means the thickness of the dielectric must be minimised. This in turn limits the maximum working voltage of the capacitor. For this reason, even though there is no fixed limit, set by the chemistry, on the working voltage of a capacitor as there is with batteries, for supercapacitors with a capacitance of over 1000 Farads or more the working voltage may be only a few volts.

For high voltage applications such as electric vehicles, a series chain of capacitors must be used to avoid exceeding the working voltage of individual capacitors and this reduces the effective capacity of the chain. For a series chain of N equal value capacitors the capacity is calculated from C=c/N where C is the capacitance of the chain and c is the capacitance of the individual capacitors. At the same time, the internal resistance of the chain is increased to R=rN, where r is the internal resistance of the capacitor, as more capacitors are added. This slows the charge-discharge rate and increases the losses.

Higher capacitances can be achieved by using parallel capacitors. In this case the capacitance of a group of N parallel capacitors is given by C=Nc. At the same time the resistance of the group is reduced and is given by R=r/N.

Capacitors are now used extensively as power back up for memory circuits and in conjunction with batteries to provide a power boost when needed. See Load sharing.

High power versions can provide high instantaneous power but they have limited capacity. See the Ragone Plot below. They are suitable for applications which require a short duration power boosts such as UPS systems which need fast take over of substantial electrical loads for a short period until back up power units, such as rotary generators or fuel cells, have switched on and reached their full output. Similarly they can be used to provide an instantaneous power boost in Electric and Hybrid vehicles.

Supercapacitors are however also ideal for absorbing the energy generated from regenerative braking in EVs and HEVs since they can accept very high instantaneous charge rates which would exceed the recommended maximum charge rate of the batteries. Used in conjunction with batteries the capacitors enable the full regenerative charge to be captured, avoiding the wasteful dumping of the excess charge which the batteries are unable to accommodate.

See more in the section on Capacitors and Supercapacitors.

History (Electrolytic Capacitors)

Heat - The Thermal Battery

There are two types of thermal batteries, one based on the thermo-electric effect which produces electricity directly from heat, outlined here, and the other based on chemical or galvanic reactions which is covered in a separate section on Thermal Batteries.

Based on the Seebeck effect, in a closed circuit made up from two dissimilar metals, an electrical potential is created between the two junction points when one junction is heated, usually by a gas burner, and the other kept cool. Since the late nineteenth century this technique has been used charge storage batteries and more recently to generate emergency power. The system is not energy efficient and is only suitable for low power applications. Modern gas powered batteries based on the Seebeck effect are still available today. They operate over a wide temperature range and are often used in conjunction with solar or wind powered batteries to provide remote or emergency power on dark, windless days.

History

Springs - The Clockwork Battery

Energy is stored in spring which is wound up by a clockwork mechanism. When released, the spring is used to drive a dynamo which provides the electrical power. This is suitable only for low capacity and low power applications and limited by the short duration of the discharge. The discharge period can however be extended by using suitable gearing. The Trevor Bayliss wind-up radio is an example of this method. His clockwork battery produced 3 volts at 55-60 milliwatts giving 40 minutes of play for 20 seconds of winding.

The energy stored in a linear spring is given by the following formula

E = ½ Kx²

Where K is the spring constant (force required per unit extension) and x is the extension of the spring.

History

Flywheels - The Kinetic Battery

Energy storage in a flywheel is as old as the potters wheel. Slow speed flywheels, combined with opportunity charging at bus stops have been used since the 1950s for public transport applications, however they are very bulky and very heavy and this has limited their adoption.

The energy stored in a flywheel id given by the following formula

E = ½ Iω²

Where I is the moment of inertia of the flywheel (ability of an object to resist changes in its rotational velocity) and ω is its rotational velocity (radians/second).

The moment of inertia is given by

I = kMr ² 

Where M is the mass of the flywheel, r its radius and k is its inertial constant.

k depends on the shape of the rotating object. For a flywheel loaded at rim such as a bicycle wheel or hollow cylinder rotating on its axis, k = 1, for a solid disk of uniform thickness or a solid cylinder, k = ½.

Modern super flywheels store kinetic energy in a high speed rotating drum which forms the rotor of a motor generator. When surplus electrical energy is available it is used to speed up the drum. When the energy is needed the drum provides it by driving the generator. Modern high energy flywheels use composite rotors made with carbon-fiber materials. The rotors have a very high strength-to-density ratio, and rotate at speeds up to 100,000 rpm. in a vacuum chamber to minimize aerodynamic losses. The use of superconducting electromagnetic bearings can virtually eliminate energy losses through friction.

The magnitude of the engineering challenge should not be underestimated. A 1 foot diameter flywheel, one foot in length, weighing 23 pounds spinning at 100,000 rpm will store 3 kWh of energy. However at this rotational speed the surface speed at the rim of the flywheel will be 3570 mph. or 4.8 times the speed of sound and the centrifugal force on particles at the rim is equivalent to 1.7 million G. The tensile strength of material used for the flywheel rim must be over 500,000 psi to stop the rotor from flying apart.

Flywheels are preferred over conventional batteries in many aerospace applications because of the following benefits

Flywheel vs Battery Energy Storage

	Energy Storage Characteristic	Resulting Benefits
5 to 10+ times greater specific energy		Lower mass
Long life (15 yr.) Unaffected by number of charge/discharge cycles		Reduced logistics, maintenance, life cycle costs and enhanced vehicle integration
85-95% round-trip efficiency		More usable power, lower thermal loads, compared with <70-80% for battery system
High charge/discharge rates & no taper charge required		Peak load capability, 5-10% smaller solar array
Deterministic state-of-charge		Improved operability
Inherent bus regulation and power shunt capability		Fewer regulators needed

Advanced flywheels are used for protecting against interruptions to the national electricity grid.

The flywheel provides power during period between the loss of utility supplied power and either the return of utility power or the start of a sufficient back-up power system (i.e., diesel generator). Flywheels can discharge at 100 kilowatts (kW) for 15 seconds and recharge immediately at the same rate, providing 1-30 seconds of ride-through time. Back-up generators are typically online within 5-20 seconds.

Flywheels have also been proposed as a power booster for electric vehicles. Speeds of 100,000 rpm have been used to achieve very high power densities, however containment of the high speed rotor in case of accident or mechanical failure would require a massive enclosure negating any power density advantages. The huge gyroscopic forces of these high speed flywheels are an added complication. Practicalities have so far prevented the large scale adoption of flywheels for portable applications.

History

Compressed air - The Pneumatic Battery

Compressed Air Energy Storage (CAES) uses pressurized air as the energy storage medium. An electric motor-driven compressor is used to pressurize the storage reservoir using off-peak energy and air is released from the reservoir through a turbine during on-peak hours to produce electrical energy. Ideal locations for large compressed air energy storage reservoirs are aquifers (water bearing rock formations), conventional mines in hard rock, and hydraulically mined salt caverns. Facilities are sized in the range of several hundred megawatts. Air can be stored in pressurized tanks for small systems.

Small systems have also been used in demonstrator hybrid cars.

History

Pumped storage - The Hydraulic Battery

Pumped storage hydroelectricity is another, relatively simple method of storing and producing large amounts of electricity to supply high peak demands. At times of low electrical demand, excess electrical capacity is used to pump water into an elevated reservoir. When there is higher demand, water is released back into the lower reservoir through a turbine, generating electricity . About 70% of the electrical energy used to pump the water into the elevated reservoir can be regained in this process. Some facilities use abandoned mines as the lower reservoir, but many use the natural height difference between two natural bodies of water or artificial reservoirs. Many pumped storage plants have been installed throughout the world. Dinorwig in Wales is an example generating 1320 MW of power.

History

Superconducting Magnetic Energy Storage (SMES) - The Magnetic Battery

Superconducting magnetic energy storage systems store energy in the field of a large magnetic coil with direct current flowing. It can be converted back to AC electric current as needed. Low temperature SMES cooled by liquid helium is commercially available. High temperature SMES cooled by liquid nitrogen is still in the development stage and may become a viable commercial energy storage source in the future.

SMES systems are large and generally used for short durations, such as utility switching events.

History

Radioisotope Thermoelectric Generators (RTG) - The Nuclear Battery

Radioisotope Thermoelectric Generators (RTGs) were designed for space applications and for providing power to remote installations such as lighthouses. Developed in 1959 by the Atomic Energy Commission at Los Alamos and introduced in 1961, these primary batteries are essentially nuclear powered heat generators which use energy emitted by the natural decay of radioactive isotopes of Plutonium (Pu-238) to provide the heat which in turn is used to generate electric power in a thermoelectric generator made from an array of thermocouples. Because the electric energy is created indirectly using the intermediate thermoelectric process the conversion efficiency is only about 4%, however the energy density of the radioactive source is thousands of times greater than Lithium Ion batteries. The technology provides long life batteries which never need recharging. Early batteries are still operational after over 25 years.

The direct conversion of nuclear energy into electricity is being developed for low power consumer applications. See Betavoltaic Batteries

History

Comparisons

The Ragone plot shows the energy storage and power handling capacity of some alternative storage techniques.

See also History 100 Battery Types

Battery Breakthrough?

A Texas company says it can make a new ultracapacitor power system to replace the electrochemical batteries in everything from cars to laptops.

By Tyler Hamilton

A secretive Texas startup developing what some are calling a "game changing" energy-storage technology broke its silence this week. It announced that it has reached two production milestones and is on track to ship systems this year for use in electric vehicles.

EEStor's ambitious goal, according to patent documents, is to "replace the electrochemical battery" in almost every application, from hybrid-electric and pure-electric vehicles to laptop computers to utility-scale electricity storage.

The company boldly claims that its system, a kind of battery-ultracapacitor hybrid based on barium-titanate powders, will dramatically outperform the best lithium-ion batteries on the market in terms of energy density, price, charge time, and safety. Pound for pound, it will also pack 10 times the punch of lead-acid batteries at half the cost and without the need for toxic materials or chemicals, according to the company.

The implications are enormous and, for many, unbelievable. Such a breakthrough has the potential to radically transform a transportation sector already flirting with an electric renaissance, improve the performance of intermittent energy sources such as wind and sun, and increase the efficiency and stability of power grids--all while fulfilling an oil-addicted America's quest for energy security.

The breakthrough could also pose a threat to next-generation lithium-ion makers such as Watertown, MA-based A123Systems, which is working on a plug-in hybrid storage system for General Motors, and Reno, NV-based Altair Nanotechnologies, a supplier to all-electric vehicle maker Phoenix Motorcars.

"I get a little skeptical when somebody thinks they've got a silver bullet for every application, because that's just not consistent with reality," says Andrew Burke, an expert on energy systems for transportation at University of California at Davis.

That said, Burke hopes to be proved wrong. "If [the] technology turns out to be better than I think, that doesn't make me sad: it makes me happy."

Richard Weir, EEStor's cofounder and chief executive, says he would prefer to keep a low profile and let the results of his company's innovation speak for themselves. "We're well on our way to doing everything we said," Weir told Technology Review in a rare interview. He has also worked as an electrical engineer at computing giant IBM and at Michigan-based automotive-systems leader TRW.

Much like capacitors, ultracapacitors store energy in an electrical field between two closely spaced conductors, or plates. When voltage is applied, an electric charge builds up on each plate.

Ultracapacitors have many advantages over traditional electrochemical batteries. Unlike batteries, "ultracaps" can completely absorb and release a charge at high rates and in a virtually endless cycle with little degradation.

Where they're weak, however, is with energy storage. Compared with lithium-ion batteries, high-end ultracapacitors on the market today store 25 times less energy per pound.

This is why ultracapacitors, with their ability to release quick jolts of electricity and to absorb this energy just as fast, are ideal today as a complement to batteries or fuel cells in electric-drive vehicles. The power burst that ultracaps provide can assist with stop-start acceleration, and the energy is more efficiently recaptured through regenerative braking--an area in which ultracap maker Maxwell Technologies has seen significant results.

On the other hand, EEStor's system--called an Electrical Energy Storage Unit, or EESU--is based on an ultracapacitor architecture that appears to escape the traditional limitations of such devices. The company has developed a ceramic ultracapacitor with a barium-titanate dielectric, or insulator, that can achieve an exceptionally high specific energy--that is, the amount of energy in a given unit of mass.

For example, the company's system claims a specific energy of about 280 watt hours per kilogram, compared with around 120 watt hours per kilogram for lithium-ion and 32 watt hours per kilogram for lead-acid gel batteries. This leads to new possibilities for electric vehicles and other applications, including for the military.

"It's really tuned to the electronics we attach to it," explains Weir. "We can go all the way down from pacemakers to locomotives and direct-energy weapons."

The trick is to modify the composition of the barium-titanate powders to allow for a thousandfold increase in ultracapacitor voltage--in the range of 1,200 to 3,500 volts, and possibly much higher.

EEStor claims that, using an automated production line and existing power electronics, it will initially build a 15-kilowatt-hour energy-storage system for a small electric car weighing less than 100 pounds, and with a 200-mile driving range. The vehicle, the company says, will be able to recharge in less than 10 minutes.

The company announced this week that this year it plans to begin shipping such a product to Toronto-based ZENN Motor, a maker of low-speed electric vehicles that has an exclusive license to use the EESU for small- and medium-size electric vehicles.

By some estimates, it would only require $9 worth of electricity for an EESU-powered vehicle to travel 500 miles, versus $60 worth of gasoline for a combustion-engine car.

"My understanding is that the leap from powder to product isn't the big leap," says Ian Clifford, CEO of ZENN, which is also an early investor in EEStor. "We're the first application, and that's thrilling for us. We took the initial risk because we believed in what they are doing. And energy storage is the game changer."

The key challenge, however, is to ensure that the barium-titanate powders can be made on a production line without compromising purity and stability. "Purification gives you better production stability, gives you better permittivity, and gives you the high voltages you're looking for," says Weir. "We've now got the chemicals certified and purified to the point we're looking for." (Better permittivity of the insulator improves the amount of charge that can be stored without letting the current leak across the two plates.)

EEStor announced this week that the first automated production line for its powder has performed as required and that permittivity will meet or exceed expectations. It also said that it achieved 99.9994 percent purity for its barium-nitrate powder, a crucial ingredient in the dialectric. San Antonia-based Southwest Research Institute independently confirmed the results.

In a traditional ultracap, that permittivity is given a rating of 20 to 30, while EEStor's claim is 18,500 or more--a phenomenal number by most accounts. "This is a very big step for us," says Weir. "This puts me well onto the road of meeting high-volume production."

Jim Miller, vice president of advanced transportation technologies at Maxwell Technologies and an ultracap expert who spent 18 years doing engineering work at Ford Motor, isn't so convinced.

"We're skeptical, number one, because of leakage," says Miller, explaining that high-voltage ultracaps have a tendency to self-discharge quickly. "Meaning, if you leave it parked overnight it will discharge, and you'll have to charge it back up in the morning."

He also doesn't believe that the ceramic structure--brittle by nature--will be able to handle thermal stresses that are bound to cause microfractures and, ultimately, failure. Finally, EEStor claims that its system works to specification in temperatures as low as -20 °C, revised from a previous claim of -40 °C.

"Temperature of -20 degrees C is not good enough for automotive," says Miller. "You need -40 degrees." By comparison, Altair and A123Systems claim that their lithium-ion cells can operate at -30 °C.

Burke, meanwhile, says that there's a big difference between making powder in a controlled environment and making defect-free devices in a large quantity that can survive underneath the hood of a car.

"I have no doubt you can develop that kind of [ceramic] material, and the mechanism that gives you the energy storage is clear, but the first question is whether it's truly applicable to vehicle applications," Burke says, pointing out that the technology seems more appropriate for utility-scale storage and military "ray guns," for which high voltage is an advantage.

Safety is another concern. What happens if a vehicle packed with a 3,500-volt energy system crashes?

Weir says the voltage will be stepped down with a bi-directional converter, and the whole system will be secured in a grounded metal box. It won't have a problem getting an Underwriters Laboratories safety certification, he adds. "If you drive a stake through it, we have ways of fusing this thing where all the energy is sitting there but it won't arc … It will be the safest battery the world has ever seen."

Regarding concerns about temperature, leakage, and ceramic brittleness, Weir did not reply to an e-mail asking him how EEStor overcomes such issues.

Nonetheless, the company has some solid backing. Its board has attracted Morton Topfer, former vice chairman of Dell and mentor to Michael Dell.

The company is also backed by Kleiner Perkins Caufield & Byers, a venture-capital powerhouse that has an impressive track record: it made early and highly successful bets on Google, Amazon.com, and Sun Microsystems, among others. Whether EEStor can translate that success to the energy sector remains to be seen.

"I'm surprised that Kleiner has put money into it," says Miller.

Weir maintains that his company will meet all of its claims, and then some. "We're not trying to hype this. This is the first time we've ever talked about it. And we will continue to meet all of the production requirements."

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Glossary of terms

ACCESS CHARGE
A fee charged subscribers or other telephone companies by a local exchange carrier for the use of its local exchange networks.

ANALOG SIGNAL
A signaling method that uses continuous changes in the amplitude or frequency of a radio transmission to convey information.

BANDWIDTH
The capacity of a telecom line to carry signals. The necessary bandwidth is the amount of spectrum required to transmit the signal without distortion or loss of information. FCC rules require suppression of the signal outside the band to prevent interference.

BROADBAND
Broadband is a descriptive term for evolving digital technologies that provide consumers a signal switched facility offering integrated access to voice, high-speed data service, video-demand services, and interactive delivery services.

CALLING PARTY PAYS
A billing method in which a wireless phone caller pays only for making calls and not for receiving them. The standard American billing system requires wireless phone customers to pay for all calls made and received on a wireless phone.

CELLULAR TECHNOLOGY
This term, often used for all wireless phones regardless of the technology they use, derives from cellular base stations that receive and transmit calls. Both cellular and PCS phones use cellular technology.

CLOSED CAPTIONING
A service for persons with hearing disabilities that translates television program dialog into written words on the television screen.

COMMERCIAL LEASED ACCESS
Manner through which independent video producers can access cable capacity for a fee.

COMMON CARRIER
In the telecommunications arena, the term used to describe a telephone company.

COMMUNICATIONS ASSISTANT
A person who facilitates telephone conversation between text telephone users, users of sign language or individuals with speech disabilities through a Telecommunications Relay Service (TRS). This service allows a person with hearing or speech disabilities to communicate with anyone else via telephone at no additional cost.

COMMUNITY ANTENNA TELEVISION (CATV)
A service through which subscribers pay to have local television stations and additional programs brought into their homes from an antenna via a coaxial cable.

CRAMMING
A practice in which customers are billed for enhanced features such as voice mail, caller-ID and call-waiting that they have not ordered.

DIAL AROUND
Long distance services that require consumers to dial a long-distance provider’s access code (or "10-10" number) before dialing a long-distance number to bypass or "dial around" the consumer’s chosen long-distance carrier in order to get a better rate.

DIGITAL TELEVISION (DTV)
A new technology for transmitting and receiving broadcast television signals. DTV provides clearer resolution and improved sound quality.

DIRECT BROADCAST SATELLITE (DBS/DISH)
A high-powered satellite that transmits or retransmits signals which are intended for direct reception by the public. The signal is transmitted to a small earth station or dish (usually the size of an 18-inch pizza pan) mounted on homes or other buildings.

E-MAIL
Also called electronic mail, refers to messages sent over the Internet. E-mail can be sent and received via newer types of wireless phones, but you generally need to have a specific e-mail account.

ENHANCED SERVICE PROVIDERS
A for-profit business that offers to transmit voice and data messages and simultaneously adds value to the messages it transmits. Examples include telephone answering services, alarm/security companies and transaction processing companies.

EN BANC
An informal meeting held by the Commission to hear presentations on specific topics by diverse parties. The Commissioners, or other officials, question presenters and use their comments in considering FCC rules and policies on the subject matter under consideration.

FREQUENCY MODULATION (FM)
A signaling method that varies the carrier frequency in proportion to the amplitude of the modulating signal.

GLOBAL POSITIONING SYSTEM (GPS)
A US satellite system that lets those on the ground, on the water or in the air determine their position with extreme accuracy using GPS receivers.

HIGH DEFINITION TELEVISION (HDTV)
An improved television system which provides approximately twice the vertical and horizontal resolution of existing television standards. It also provides audio quality approaching that of compact discs.

INTERACTIVE VIDEO DATA SERVICE (IVDS)
A communication system, operating over a short distance, that allows nearly instantaneous two-way responses by using a hand-held device at a fixed location. Viewer participation in game shows, distance learning and e-mail on computer networks are examples.

INSTRUCTIONAL TELEVISION FIXED SERVICE (ITFS)
A service provided by one or more fixed microwave stations operated by an educational organization and used to transmit instructional information to fixed locations.

LANDLINE
Traditional wired phone service.

LAND MOBILE SERVICE
A public or private radio service providing two-way communication, paging and radio signaling on land.

LOW POWER FM RADIO (LPFM)
A broadcast service that permits the licensing of 50-100 watt FM radio stations within a service radius of up to 3.5 miles and 1-10 watt FM radio stations within a service radius of 1 to 2 miles.

LOW POWER TELEVISION (LPTV)
A broadcast service that permits program origination, subscription service or both via low powered television translators. LPTV service includes the existing translator service and operates on a secondary basis to regular television stations. Transmitter output is limited to 1,000 watts for normal VHF stations and 100 watts when a VHF operation is on an allocated channel.

MUST-CARRY (Retransmission)
A 1992 Cable Act term requiring a cable system to carry signals of both commercial and noncommercial television broadcast stations that are "local" to the area served by the cable system.

NETWORK
Any connection of two or more computers that enables them to communicate. Networks may include transmission devices, servers, cables, routers and satellites. The phone network is the total infrastructure for transmitting phone messages.

NUMBER PORTABILITY
A term used to describe the capability of individuals, businesses and organizations to retain their existing telephone number(s) –– and the same quality of service –– when switching to a new local service provider.

OPEN VIDEO SYSTEMS
An alternative method to provide cable-like video service to subscribers.

OPERATOR SERVICE PROVIDER (OSP)
A common carrier that provides services from public phones, including payphones and those in hotels/motels.

PAGING SYSTEM
A one-way mobile radio service where a user carries a small, lightweight miniature radio receiver capable of responding to coded signals. These devices, called "pagers," emit an audible signal, vibrate or do both when activated by an incoming message.

PERSONAL COMMUNICATIONS SERVICE (PCS)
Any of several types of wireless, voice and/or data communications systems, typically incorporating digital technology. PCS licenses are most often used to provide services similar to advanced cellular mobile or paging services. However, PCS can also be used to provide other wireless communications services, including services that allow people to place and receive communications while away from their home or office, as well as wireless communications to homes, office buildings and other fixed locations.

PRESCRIBED INTEREXCHANGE CHARGE (PICC)
The charge the local exchange company assesses the long distance company when a consumer picks it as his or her long distance carrier.

ROAMING
The use of a wireless phone outside of the "home" service area defined by a service provider. Higher per-minute rates are usually charged for calls made or received while roaming. Long distance rates and a daily access fee may also apply.

SATELLITE
A radio relay station that orbits the earth. A complete satellite communications system also includes earth stations that communicate with each other via the satellite. The satellite receives a signal transmitted by an originating earth station and retransmits that signal to the destination earth station(s). Satellites are used to transmit telephone, television and data signals originated by common carriers, broadcasters and distributors of cable TV program material.

SATELLITE HOME VIEWER IMPROVEMENT ACT OF 1999 (SHVIA)
An Act modifying the Satellite Home Viewer Act of 1988, SHVIA permits satellite companies to provide local broadcast TV signals to all subscribers who reside in the local TV station’s market. SHVIA also permits satellite companies to provide "distant" network broadcast stations to eligible satellite subscribers.

SATELLITE MASTER ANTENNA TELEVISION (SMATV)
A satellite dish system used to deliver signals to multiple dwelling units (e.g., apartment buildings and trailer parks).

SCANNER
A radio receiver that moves across a wide range of radio frequencies and allows audiences to listen to any of the frequencies.

SERVICE PLAN
The rate plan you select when choosing a wireless phone service. A service plan typically consists of a monthly base rate for access to the system and a fixed amount of minutes per month.

SERVICE PROVIDER
A telecommunications provider that owns circuit switching equipment.

SLAMMING
The term used to describe what occurs when a customer’s long distance service is switched from one long distance company to another without the customer’s permission. Such unauthorized switching violates FCC rules.

SPECTRUM
The range of electromagnetic radio frequencies used in the transmission of sound, data and television.

SUBSCRIBER LINE CHARGE (SLC)
A monthly fee paid by telephone subscribers that is used to compensate the local telephone company for part of the cost of installation and maintenance of the telephone wire, poles and other facilities that link your home to the telephone network. These wires, poles and other facilities are referred to as the "local loop." The SLC is one component of access charges.

TARIFF
The documents filed by a carrier describing their services and the payments to be charged for such services.

TELECOMMUNICATIONS RELAY SERVICE (TRS)
A free service that enables persons with TTYs, individuals who use sign language and people who have speech disabilities to use telephone services by having a third party transmit and translate the call.

TELEPHONY
The word used to describe the science of transmitting voice over a telecommunications network.

TTY
A type of machine that allows people with hearing or speech disabilities to communicate over the phone using a keyboard and a viewing screen. It is sometimes called a TDD.

UNBUNDLING
The term used to describe the access provided by local exchange carriers so that other service providers can buy or lease portions of its network elements, such as interconnection loops, to serve subscribers.

UNIVERSAL SERVICE
The financial mechanism which helps compensate telephone companies or other communications entities for providing access to telecommunications services at reasonable and affordable rates throughout the country, including rural, insular and high costs areas, and to public institutions. Companies, not consumers, are required by law to contribute to this fund. The law does not prohibit companies from passing this charge on to customers.

VERY HIGH FREQUENCY (VHF)
The part of the radio spectrum from 30 to 300 megahertz, which includes TV Channels 2-13, the FM broadcast band and some marine, aviation and land mobile services.

VIDEO DESCRIPTION
An audio narration for television viewers who are blind or visually disabled, which consists of verbal descriptions of key visual elements in a television program, such as settings and actions not reflected in dialog. Narrations are inserted into the program’s natural pauses, and are typically provided through the Secondary Audio Programming channel.

Attorney General (AG) of your State - Each state has a consumer protection
agency within the AG's office. Go to your state website example: http://www.state.gov

Better Business Bureau (BBB) - http://www.bbb.com

Federal Trade Commission (FTC) - http://www.ftc.gov
or call 888 225-5322

Federal Communications Commission (FCC) - http://www.fcc.gov

State Public Utilities Commisssion (SPUC or PUC) see the check list at
http://www.fcc.gov/wcb/iatd/state_puc.html

United States Postal Service (USPS) http://www.usps.com/postalispectors/ (mail fraud)