Skeptics question whether broadband over power line technology can overcome its late market arrival; broadband pipes that use cable or phone companies' digital subscriber lines (DSL) have become the preferred means of Internet delivery for most households moving beyond balky dial-up connections. But on one critical measure of performance, BPL holds its own. BPL's download speeds range from 500 kilobits per second to 4 megabits per second, according to Brett Kilbourne, director of regulatory services for the United Power Line Council, an organization that promotes BPL. That's roughly on par with conventional broadband options. Cable modems typically offer download speeds of 2 megabits per second, while digital subscriber lines (DSL) provide an average of about 860 kilobits per second, according to comScore Networks, a  market research firm in Reston, VA. Solvay's BPL trial ran in 35 homes over a six-month period and found the user bandwidth to be comparable to that of DSL, according to Montone.

Still unknown is whether expanding into the broadband business makes good sense for utilities, many of which were burned by misguided telecom efforts in the 1990s. Not every power company will see BPL as a core service, says Garrett Johnston, an analyst for Chartwell, a retail-energy research firm in Atlanta. Those utilities that are considering BPL are looking at ways to minimize the risk, such as selling the pole space or partnering with vendors who will promote the service "since utilities aren't known for marketing in a competitive environment," says Johnston.

Potential profits aside, how exactly does BPL work? Vendors implement BPL in diverse ways, says Dave Waks, co-author of the Broadband Home Report.  Some employ HomePlug technology, an industry standard for high-speed networking over power lines. Some use proprietary technology. Some use wireless technology to carry signals from the pole to the home. But each approach relies on a common set of elements, Waks says. Data leaves the modem and travels to a corresponding device on the nearest pole-mounted transformer. A power substation relays the signals to a conventional Internet backbone line.

Critics point out that power lines are a harsh environment, already cluttered with interference produced by assorted home accoutrements such as halogen lights and garage-door openers. Ham radio operators protest that BPL will travel over the same frequencies that they're licensed to use. Following the lead of the Bush administration, which has endorsed the idea of making broadband more universally available, the FCC came down firmly on the side of the technology earlier this year when it approved the use of BPL equipment despite finding that the gear couldn't meet its guidelines on radio-frequency emissions.

The National Telecommunications and Information Administration wasn't as kind in a little-noticed report issued in April. The NTIA, an agency of the Department of Commerce that advises the White House on all matters telecom, found that BPL-generated data signals posed genuine interference risks to radio communication. The NTIA findings "surprised" the United Power Line Council, according to Kilbourne, who says his organization is "working through some of the findings."

Pleasing federal officials is important. But so will be a few static-free service roll-outs where BPL providers prove that their power grid is ready for twenty-first century communications.