Reprinted with permission from the Feb. 2005 issue of Public CIO.
Is America ready to plug in to the Internet? For years we connected to the Web and e-mail via telephone lines. High-speed service arrived when cable TV companies introduced the cable modem and phone companies offered DSL service in 1997 and 1998 respectively.
Now your electrical utility is ready to join the party. In 2004, broadband over power lines (BPL), or power line communication (PLC), made its debut. In early February 2004, Manassas, Va., became the first city to deploy BPL in the United States.
Because any building housing people has an electrical outlet, BPL technology can potentially minimize the digital divide, bringing high-speed Internet service to rural areas. BPL could also add significant competition to the rather uncompetitive broadband market.
BPL allows electric utilities to use existing infrastructure to offer new services, and Potomac Electric Power Company (Pepco) Spokesman Bob Dobkin told The New York Times that the company's main interest in BPL is for better utility management. "It enables you to identify problems without having to send someone out," he said.
Pepco has a BPL pilot in about 500 homes in Potomac, Md.
BPL has progressed rapidly since 2002, from a handful of trials to almost 100 pilots, tests and early stage commercial deployments in North America, according to Developments in Broadband over Power Lines, a report by The Shpigler Group.
BPL offers a mix of competitive deployment costs, service capabilities and operational benefits, and could use existing power line infrastructure in combination with fiber-optic feeder systems or wireless technology to offer broadband access. BPL is suited for smart home services, energy management and other utility applications, according to the report
How It Works
In BPL/PLC access, a computer plugged into a common electrical outlet is automatically connected to high-speed Internet. Using technological principles of modems, radio and wireless networking, BPL is capable of data speeds between 500 Kbps and 3 Mbps -- which is equivalent to DSL and cable, according to HowStuffWorks.com. In some cases, wireless links are installed on utility poles, and the data is sent wirelessly into homes.
BPL transmits data over 7,200-volt medium-voltage power lines, bypassing high-voltage lines because too much power flows on them -- 155,000 to 765,000 volts -- for data transmission, according to HowStuffWorks.com.
The data degrades as it travels along the medium-voltage lines. To counter this, devices are installed on the lines that take in the data and repeat it as a new transmission, amplifying it for the continuing trek.
Broadband signals cannot pass through a transformer, so a coupler provides a data path around it, allowing data to move easily from the 7,200-volt line to the 240-volt line and into the house. Another approach is to install wireless technology, allowing the data signal to bypass the transformer to a wireless receiver inside the home or business.
Following the Rules
Both electricity and the radio frequency used to transmit data vibrate at certain frequencies, according to HowStuffWorks.com, so for data to transmit cleanly from point to point, it must vibrate at a dedicated band of the radio spectrum -- one that lacks interference from other sources.
In October 2004, the FCC established standards allowing power utilities to provide broadband to customers, competing with DSL, cable, and even meshed Wi-Fi networks and future WiMAX deployments. The FCC also requires that BPL avoid specific frequency bands and frequency exclusion zones to protect aeronautical and aircraft communications.
Licensed wireless users, such as cellular and ham radio operators, have objected to the FCC's report and order, saying they