Broadband over power lines: an idea grounded in reality?

As shocking as it may seem, the long-sought "third pipe" to the Internet already may be in your home--as well as in nearly everybody else's.

In April, FCC Chairman Michael Powell viewed a demonstration project for a new technology that, at first glance, may offer the possibility of revolutionizing the way rural Americans can access advanced services.

The suburban Washington, D.C., project, conducted by Current Technologies in cooperation with the Potomac Electric Power Co. (PEPCO), sends Internet data over standard electric power lines.

Supporters of the new technology argue that not only can it effectively compete with telephone digital subscriber line (DSL) and digital cable service, but under the right conditions, it can surpass those incumbent technologies.

Chairman Powell apparently was impressed by what he saw, noting that he "witnessed first hand...[that] the potential of this new technology is immense." The new technology's detractors, however, are not nearly as certain.

The Basics

Part 15 of the FCC's rules cover two basic types of power line equipment. Carrier current systems transmit radio frequency (RF) energy over a power line to a receiver connected to the same power line. Signals either may be received by direct connection to the power line or by radiation of RF signals from the power line. Power line systems, which are not subject to the same emissions limits as carrier current systems, are used by electricity providers for general supervision of the power system.

Using alternating current (AC) power lines as a transmission medium is hardly a new idea. Colleges and universities long have pumped low-power AM radio signals into dormitories over AC lines. Home intercom systems use in-house wiring to transmit messages from room to room. Telephone systems that utilize a home's power lines allow for the placement of wireline telephones in rooms with power outlets, but no telephone jacks.

Operating on an unlicensed basis under Part 15 of the FCC's rules, broadband over power line (BPL) systems are carrier current systems that, typically, have operated on frequencies below 2 MHz. There are two primary types of BPL systems: in-house BPL, which operates within a building, and access BPL, which transmits by way of utility poles and medium voltage electric power lines.

How It Works

In an in-house BPL system, the user simply plugs a BPL adapter module into a power outlet and, thus, is able to communicate over the home's electrical wiring with other BPL modules in the home. In effect, this allows users to establish a local area network (LAN) within their house, using the home's existing AC power lines to connect the various devices on the network.

These devices can include personal computers, set-top boxes, information appliances and consumer electronics devices. When connected via a LAN, these devices allow for a number of useful functions, including sharing files between PCs, shared Internet access, shared printing and device control.

Access BPL, on the other hand, can be used to deliver high-speed Internet and other broadband services to retail end users, providing the "last mile" delivery of broadband services to hard-to-reach customers. In addition, the utilities themselves can use access BPL to better coordinate their power transmission and distribution systems.

Several electric utility companies are running BPL demonstration projects and market tests, including Ameren Corp., American Electric Power, Cinergy, Consolidated Edison, Los Angeles Department of Water and Power, PEPCO/Conectiv, PPL Telecom, Progress Energy, The Southern Co., TXU, and the City of Manassas, Va. For the most part, the results of these trials are being kept secret by the utilities, either due to non-disclosure agreements with equipment suppliers or for future competitive reasons.

Possible Benefits...

Utilities: For the power companies, the ability to leverage their existing physical plant to provide a highly valued service is ideal. These companies already own the poles and lines that access virtually ever residential and business customer in the United States. Providing these customers with broadband over power lines would simply require adding equipment to their poles. BPL also offers the potential to improve a utility's ability to accomplish such key system-management tasks as remote power outage notification, load management and balancing, and remote meter reading.

On the down side for electric companies, some already have tried to infiltrate communications, many with less than successful results. Those that invested heavily in fiber optic cable deployment in the mid-1990s were devastated by the telecom collapse of the latter part of the decade. Consequently, some are somewhat gun-shy about attempting a similar venture. These companies are carefully watching those pioneers who have established demonstration projects. Should these projects prove the viability of broadband over power lines, expect other power companies to quickly enter the market.

Customers: Certain customer segments could benefit from BPL, as well. Those customers living in unserved or underserved areas, due to terrain, remote location or the expense of upgrading existing infrastructure, may find that BPL provides them access to advanced services they would not have otherwise. Even in areas that are so rugged and remote that they cannot economically be served via cable or DSL, electric power lines are ubiquitous.

From a price standpoint, it seems likely that such service could run $30 per month, and prices as low as $20 per month are not beyond the realm of possibility Cable and DSL broadband services, in comparison, typically cost anywhere from $40 to $60 per month.

Other: The ability to offer BPL services could add a degree of redundancy to the nation's advanced services infrastructure, a key factor in this time of heightened national security concerns. In addition, the increased ubiquity of advanced services at affordable rates will result in productivity gains that benefit all Americans.

... Potential Pitfalls

As noted, BPL systems typically have operated on frequencies below 2 MHz. Communication capabilities over the power wires have been limited. For starters, certain devices on the circuit--such as vacuum cleaners, fans and appliance motors--impede communication with their significant and unpredictable interference.

New technologies offer the promise to ameliorate these problems, by operating on multiple carriers that are spread over a wide spectrum (e.g., from 4.5 MHz to 21 MHz) with adaptive algorithms to overcome the noise in the line. As a result, it has been claimed that speeds of 14 Mbps have been achieved for in-house communications, and that access BPL has attained speeds comparable to those of DSL or cable broadband service. Current FCC rules, however, were not designed to cover this next generation BPL equipment (see sidebar on page 18).

Significant problems will need to be addressed outside of the home, as well. Since overhead power lines are not insulated, the potential for interference between different types of communications transmissions must be overcome. A number of third parties already are paying electric companies for the use of their poles; interference with and among these pole attachments must be addressed for the technology to be fully viable.

A potentially fatal flaw is the extreme difficulty in successfully passing data signals through the step-down transformer that converts the medium-voltage power from transmission lines to the low-voltage (220/110 volts) power that ultimately enters the home.

A number of companies have proposed various solutions to this problem, ranging from separating the data signal from the electric current to bypass the transformer, to utilizing wireless technology to transmit the data signal to the customer before it reaches the transformer. Finding a solution that not only solves the problem but also is cost effective will be critical to facilitating the widespread distribution of BPL technology.

Policy Matters

Numerous policy implications must be addressed before BPL can reach its full potential. Electric companies must not be allowed to cross-subsidize their non-regulated communications business from their regulated energy business. Other important matters--such as the impact of BPL on universal service--cannot be ignored, either.

A further uncertainty is the question of whether state regulators will allow electric utilities to provide BPL service. Typically, state regulators have a say in how power companies make use of their physical assets. This is new and uncharted territory; the ultimate outcome at this point is unclear.

While the provision of broadband services over ordinary power lines offers the potential for a number of significant advantages to unserved and underserved customers, there are numerous technical and regulatory hurdles that must be overcome. In the meantime, continued work to solve these problems--and ensuring that BPL is regulated in such a way as to allow for fair and nondiscriminatory competition with existing broadband technologies--will bring widespread commercial availability of this promising technology that much closer to reality.

RELATED ARTICLE: The FCC on BPL

Part 15 of the FCC's rules do not cover the new generation of broadband over power line (BPL) devices operating across a wider swath of spectrum than previous devices. Neither do the rules provide for a means of measuring emission from carrier current systems.

In recognition of these deficiencies, the FCC in late April issued a notice of inquiry (NOI) to gain additional information on a number of topics related to BPL systems. (An NOI, in effect, is the commission's mechanism for collecting additional information and technical data from interested parties on a particular topic.) The commission seeks guidance on:

* The state of high-speed BPL technology

* The potential interference effects, if any, on authorized spectrum users

* Test results from BPL experimental sites

* The appropriate measurement procedure for testing emission characteristics for all types of carrier current systems

* Change that might be needed in Part 15 technical rules and the equipment approval process to foster the development of BPL and to ensure that interference is not caused by other services as a result of this technology

Through this notice, the FCC wants input from all interested parties-power companies, telecommunications companies, the general public, etc. The FCC ultimately will use the information to shape subsequent BPL rulemaking. Comments are due July 7; reply comments are due August 6.

Rick Schadelbauer

Rick Schadelbauer is NTCA's economist. He can be reached at [e-mail].