Broadband via electrical wires is certainly an encouraging idea since nearly every home in the world is served by power lines. What’s more, most residences are threaded with electrical wires terminating in multiple outlets in almost every room. So homeowners can get a high-speed Net connection — up to 3 megabits per second — just by plugging a special modem into any outlet. That matches cable modem speeds and outpaces most DSL offerings.
What is BPL?
Broadband over Power Lines (BPL) also goes by a few other names and acronyms: Power Line Communications (PLC, Power Line Telecommunications (PLT), and Power Line Broadband (PLB) are terms also used. Most of these papers and links use the term “BPL.” There are a number of types of PLC systems, using different approaches and architecture. All are “carrier-current” systems, a term used to describe systems that intentionally conduct signals over electrical wiring or power lines.
The principle behind BPL is simple: Because electricity courses over just the low-frequency portions of power lines, there’s room for data to stream over higher frequencies. For years, utilities have sent basic network-maintenance data across their lines at relatively low data rates. Now, by installing more sophisticated computer chips into the network, they can send and receive fast data streams for more high-bandwidth applications, such as real-time, always-on meter reading. (Say good-bye to the friendly meter reader.) And for the first time they can offer new customer services, such as voice-over-Internet or even video on demand.
That, however, will require significant upgrades of utility substations and power lines. And nobody knows exactly how big an investment will be necessary. First, power companies have to mount boxes on certain utility poles to deliver data signals. Early estimates of installation costs range from $50 to $150 per home passed, plus $30 to $200 more for modems in each home, according to a study by EPRI and its consulting arm, Primen. Internet service provider EarthLink Inc. (ELNK ), which is testing BPL schemes with Con Edison, says that to make money from selling broadband access at $20 to $30 a month, a utility may have to get installation costs down to $20 per home passed and less than $100 per modem.
Given the challenges, utilities will welcome any cost savings from improved energy management. By injecting intelligence into the farthest reaches of the power system, utilities can monitor their networks in ways never before possible. Currently, for example, power companies don’t know about local outages until customers report them. With BPL systems watching the flow of data to individual homes, they can pinpoint the neighborhoods without light. While testing residential broadband service in Briarcliff Manor, N.Y. this summer, Con Edison discovered that BPL could help detect impending faults. A residential customer noticed that his Web service was slowing down. Con Edison crews traced the problem to a cracked insulator on a pole next to his house. Now the company is modeling normal circuit conditions, then looking at even slight deviations to spot budding problems on its systems. That’s a far cry from periodic street maintenance checks, which Con Edison and others mainly rely on today.
In an era of increasing power usage by computers and other digital devices, many utilities are hoping BPL will bring them closer to an elusive goal: demand management. To encourage conservation, power companies would like to charge customers more during peak demand and less at other times. To bill accordingly, they need to measure how much power a home consumes every minute of the day. BPL could help by taking constant measurements. Some experts argue that existing approaches, using two-way pagers, are good enough and that new wireless options are cheaper. But BPL proponents say their wires are faster and more reliable.
Today the very idea of a smart electrical network is in its infancy. But demand for cheap Web access is mounting and so is the need for better power management. To satisfy both ends, utilities could embrace broadband and bring the electrical system into the Internet Age.
Web Access from Wall Outlets
One day soon, getting a broadband connection at home could be as easy as plugging a cord into an electrical outlet in the wall. The same power lines that deliver electricity to light rooms and run refrigerators will transport messages, music, and video across cyberspace. To link up computers, music players, and TV set top boxes in a home network, people will no longer have to mess with a tangle of wires or Wi-Fi settings. Over the powerlines, they’ll have the convenience of plug-and-play.
Many power companies on the US and the world over are exploring so-called broadband over powerline (BPL). BPL deployment would bring more competition to telephone and cable companies that sell web access, more Internet penetration to rural areas and hopefully lower broadband rates for the Broadband Internet users worldwide.
There is Concern: RF Interference
Because power lines are not designed to prevent radiation of RF energy, BPL represents a significant potential interference source for all radio services using this frequency range, including the Amateur Radio Service. Overhead electrical power lines and residential wiring act as antennas that unintentionally radiate the broadband signals as radio signals throughout entire neighborhoods and along roadsides. Interference has been observed nearly one mile from the nearest BPL source.
Others lean on worldwide trial failures as strong evidence that the technology is doomed-for-obsolescence; during its run bringing plenty of trouble (and interference) to areas contemplating the option.
The F.C.C. Clears Internet Access by Power Lines
Clearing the way for homes and businesses to receive high-speed Internet services through their electrical outlets, the Federal Communications Commission adopted rules on October 14/04 that will enable the utility companies to offer an alternative to the broadband communications services now provided by cable and phone companies.
For the electric companies’ part, broadband Internet service is more than a year away from becoming widely available. But the agency’s ruling is expected to increase significantly the level of investment and interest by the utilities, which had been stymied in previous attempts to offer new services over power lines. They reach more American homes than either telephone lines or television cables.
So far, the technology has been limited mainly to experiments around the country, although a commercial version recently became available in some communities near Cincinnati.
Known as broadband over power lines, or B.P.L., the technology uses a special modem that plugs into electrical outlets. So far, it has been offered at speeds of 1 to 3 megabits a second, which is comparable to broadband service over cable modems or conventional phone lines – though not as fast as the 5 megabits a second achievable through the residential fiber optic lines just now being introduced by the Bell companies.
An obstacle to the use of power lines to carry communications traffic has been the electromagnetic interference the technology can cause to various types of radio signals. The commission ruled that it would tolerate a small amount of radio interference in certain areas by the new service in exchange for making the broadband market more competitive.
Amateur radio operators and public safety officials had asked the commission to move slowly in the area because of the interference created by the service. The agency responded by setting up a system to monitor interference and restricting the service in areas where it could jeopardize public safety, like areas around airports and near Coast Guard stations.
Officials noted that there have already been field tests in 18 states of the B.P.L. technology. One company, Current Communications, has recently begun to offer broadband service near Cincinnati in a joint venture with Cinergy, the Midwest power and energy company. The service is priced at $29.95 to $49.95 a month, depending on the speed.
While some regulatory and technical issues remain, the technology offers enormous promise because the power grid is ubiquitous. The costs to the industry to offer the new service would be comparatively small, and the possible returns on those investments could be high. If the utility companies do begin to offer the broadband service more widely, they would also be likely to enter the telephone business by offering phone services over the Internet, just as phone and cable companies have begun to do.
The new technology would not only offer greater competition in the broadband market, but would also allow consumers to easily create networks in their home through electrical outlets. And adding communications abilities to power lines would permit electric companies to better manage the power grid.
The F.C.C., however, has pushed aside a number of vital issues for another day, including questions of whether utility companies would have to contribute to the telephone industry’s universal service fund and provide access to people with disabilities, and whether measures would be put in place to ensure market competition.
Several projects are ready for adoption of broadband in the United States. Current Communications, a private company in Germantown, Md., hopes to have in place a B.P.L. Internet network passing by 50,000 homes by the end of 2004. The posibilities for B.P.L. are enormous