Whether a telecommuter has to get
a big report to the big cheese in little time, or whether an avid collector
finds the one item missing from her curio up for bid on eBay with time running
out, many consumers feel they absolutely need fast Internet access.
For many people, however, the
digital divide - being too far from existing telephone digital subscriber lines
(DSL) and cable network infrastructure - makes buying broadband Internet access
impossible or exorbitant.
Enter broadband over power lines
(BPL), or the provision of high- speed Internet over existing power lines. The
key word here is existing. In rural and out-of-the-way areas, the initial
capital cost of installing the necessary infrastructure for DSL or cable networks
more than outweighs the potential payback from future use. This is known as the
last mile problem.
The lure of BPL is its potential
to go anywhere existing power lines go, which is pretty much everywhere.
Besides, BPL has the potential for much faster transmission rates. Using a
computer simulation, Pennsylvania State University researchers determined that
under optimal conditions, the maximum achievable transmission rate for BPL is
close to a gigabit per second per kilometer.
Under same conditions and same
length of line, copper cable [DSL] or coaxial lines [cable] don't come close,
said Mohsen Kavehrad, a Penn State professor of electrical engineering and a
co-author of the study. The reason for that is simple: With the copper and
coaxial cable, the ground wire is right next to the conductor. This creates a
lot of loss. With power lines, there is a 30-foot spacing between wires and the
ground.
But creating the optimal
conditions for BPL does prove to be a bit problematic. The trick is to keep the
electric current from interfering with BPL's radio-frequency (RF) energy that
travels on the same line. In theory, the two vibrate at different frequencies
and wouldn't interfere with each other. But, especially at high voltages,
electricity doesn't vibrate at a consistent frequency. That amount of power
jumps all over the spectrum, creating a bouncing signal that can severely limit
capacity.
What BPL providers must do is
avoid high-voltage lines, instead transferring the data off of traditional
fiber-optic lines onto medium-voltage power lines, which carry a more
controllable 7,200 volts of electricity.
Because data can only travel so
far on the medium-voltage lines before it degrades, the BPL providers then must
install repeaters - special devices that amplify a fading data signal. Also
necessary is new RF coupling equipment that bypasses data-blocking transformers
that change line current from 7,200 volts to house-appropriate 240 volts.
Most BPL providers have chosen to
forgo the additional conditioning required to achieve the very high
transmission rates modeled by the Penn State researchers, figuring that
customers won't place enough value on the increased capacity.
Still, the expense of the other
power grid augmentations has some questioning the feasibility of BPL.
BPL advantages
Jay Birnbaum, vice president of
Current Communications Group LLC, is not one of the naysayers. The privately
held Germantown company where Birnbaum works is further along in testing and
deploying BPL than any other company. With a pilot program in Rockville (in
partnership with Washington-based utility PEPCO), and a large-scale rollout in
the greater Cincinnati area, the company is aggressively promoting the merits
of BPL through its affiliate Current Technologies LLC.
Since May 2004, Current Technologies
and its power company partner, Ohio-based Cinergy Corp., have made BPL
available to 50,000 homes in Cincinnati, with a penetration rate north of 10
percent, said Birnbaum. Significantly, more than half of the recruits defected
from DSL or cable; about 40 percent migrated from dial-up.
So far, Current Technologies and
Cinergy are recording 90 percent satisfaction rates, said Birnbaum. (It remains
unclear how Cinergy's recent announcement of its sale to Duke Energy Corp. for
$9 billion will affect future BPL implementation.)
Advantages of BPL subscription
include identical upload and download speeds, the freedom to move from room to
room (every electrical outlet is a port), and the ease of putting multiple
computers online.
Monthly charges start at $29.95
for a maximum speed of 1 megabit per second, to $39.95 for a maximum speed of 3
megabits per second. For comparison, the $29.95 basic plan offers the speed of
cable for a DSL price (DSL is generally slower and less expensive; cable is
faster and pricier). Included in the price is a plug-and-play modem that
connects to a PC via USB or Ethernet. A Wi-Fi-enabled wireless modem is extra.
Shows promise
There are, however, some
remaining concerns surrounding BPL. Some claim that BPL interferes with
short-wave radios used by ham radio operators and some emergency responders.
Birnbaum says this hasn't been a problem for his company: We have had a sum
total of zero [interference] complaints.
Also, there is some worry there
still won't be an economic incentive to reach the most rural homes because of
the additional equipment required to make power distribution lines BPL-ready.
For Current, the hardest part of
implementing BPL has not been convincing customers, rather the most difficult
thing is to get utilities to deploy the technology, said Birnbaum.
He expects this obstacle will
cease as power companies begin to understand how BPL deployment ultimately will
yield a smarter power grid. Eventually, power companies will be able to enjoy
automated meter reading, remote switching, and power outage and restoration
tracking in real time.
With Cinergy, before anyone
called them, we notified them when there was an outage and where it occurred,
said Birnbaum.
And that's not all. By October,
Current plans to use BPL to offer Internet telephone services, known as Voice
over Internet Protocol, or VoIP.
Clearly, the technology shows promise. With continued favorable rulings
from the Federal Communication Commission and support from the White House
(President Bush is a booster), BPL should increasingly become a viable
alternative to DSL and cable.
Copyright 2005 Dolan Media Newswires
Provided by ProQuest Information and Learning Company. All rights Reserved.
