Imagine turning on your radio or other audio device to listen to your favorite talk radio station and hearing an annoying buzz in the background. Worse yet, you are a ham radio enthusiast, and when you try to DX the world, your reception is blanked with tremendous interference. Well, that’s the initial experience that many people have had so far with BPL—Broadband Internet over the Power Line.

The concept is fairly simple and the electric power grid is ubiquitous. Why not use the same wires that carry power into every home to also carry Internet service? Power utilities claim they aren’t just building a BPL network and then marketing it against DSL, satellite, and cable technologies. Perhaps overoptimistically, part of their cost justification is that a BPL network also allows them to monitor overall power use, outages, and grid trouble spots so that they can quickly and efficiently reroute power around problem areas.

Of course, like any new technology, there are two sides to the coin. Yes, you can piggyback the high-frequency Internet communication signals on the power line and turn every power company into an instant ISP. Unfortunately, the obvious consequence of putting high-frequency signals on top of an uninsulated and unshielded wire meant for 60-Hz power makes it radiate like a giant antenna. Worse yet, the frequencies typically used are the same ones ham enthusiasts relish because they have lots of long-distance bounce. When these frequencies are applied to a medium-voltage power line running for miles, it is theoretically possible that a BPL signal in South Dakota could be picked up in Texas.

EMI from the BPL-enabled medium voltage lines that link electric power substations is the major source of interference. A second-generation BPL architecture from Motorola called high-speed wireless Canopy eliminates much of this by using wireless transceivers that connect the Internet communication signals to the low-voltage side of the power line going into the home. Superimposing data signals on the low-voltage side of the AC line would be similar to existing commercial power-line networking devices that radiate very little.

The bad news is that in order to make a Canopy BPL system without all the EMI, they are pretty much taking on the same installation costs of competing ISP technologies. Like cable and DSL, they have to run communications via coax or fiber out to local communication hubs that are then further divided into wireless connected grids serving local customers. In my opinion, putting a BPL box on every power transformer (and I’m the only house on my transformer) is no less expensive than making the service-area modem clusters typically used for cable or DSL. There are an awful lot of utility transformers in this country.

Power utilities are touting the benefits of BPL to rural customers. However, with the infrastructure investment required for a BPL system, the only places it will be able to compete with existing Internet services will be large population centers. These areas are already well saturated with broadband service and their ISP competitors have their infrastructure in place. From a commercial perspective, the best opportunity for BPL isn’t where homes are a mile or two apart, but rural communities where there are several thousand people who still don’t have broadband at all or in developing countries that have electricity but not telecom networks.

In the end, even if the utility companies con the politicians into suggesting that electric customers might subsidize this improved “power grid monitoring” infrastructure, the real challenge to BPL is evolving technology. The window for bandwagon acceptance of power line-based Internet service in any form is shrinking. Some BPL advantages are obvious, and it allows electric utilities to deliver data and communications as well as provide more effective energy management services in the home. However, as cable, DSL, wireless broadband, and especially the new Wi-Max technology make bigger and bigger inroads while continuing to reduce costs and gain market share, the window for BPL to make its mark keeps getting smaller and smaller. Personally, I would love to see a successful and cost-effective implementation of BPL, even if it only serves to put more pressure on present service providers and keep them honest. But I don’t want to see my electric bill increasing simply to subsidize a technology where there is no market for it.