Aust & NZ
This page considers use of domestic and other power lines
for internet traffic.
It covers -
- 'broadband over power line' technologies as a panacea
or a second-rank solution
sense of the technologies - access and inhouse BPL
- is BPL an 'also ran' technology that was too late
to move from the laboratory to the market?
- key impediments to uptake, including interference,
competition from other technologies, consumer anxieties
and indifferent industry support
following pages discuss the uncertain business case for
BPL, exploration of broadband powerline communication
in Australia, and trials overseas.
As the name suggests, digital powerline communication
(PLC) - or broadband over power lines (BPL), Power Line
Telecommunications (PLT) or Power Line Broadband (PLB)
- uses existing electrical power grids rather than dedicated
telephone wiring or television cable to provide access
to the net.
BPL is a label for a group of technologies that have been
a mechanism for freeing consumers from "the tyranny
of the telephone company". Enthusiasts have characterised
BPL as potentially offering broadband connectivity that
is unavailable through existing telephone lines, that
drives improvement in the performance of incumbent connectivity
providers such as Australia's Telstra and that provides
substantial new revenue for utility
Others have forecast use of BPL in bridging digital
divides in the Third World, "bringing broadband
to isolated village and farms". It is acclaimed because
the infrastructure is "already there", so that
there is ostensibly no need to deploy fibre, satellite,
WiMAX or other new communication infrastructure.
It has however been criticised as technologically problematical,
commercially unviable and over-sold.
Technological criticisms centre on interference with existing
users of the radio frequency (RF) spectrum. Although those
users are sometimes dismissed as 'ham radio operators'
they encompass emergency service agencies, aviators, commercial
broadcasters and other entities. RF transmissions are
licenced because space in the spectrum is finite. Adoption
of BPL in most jurisdictions accordingly requires permission
by telecommunication regulators. That permission often
has not been forthcoming, because regulators have not
been satisfied during technical trials.
Commercial criticisms centre on the uncertain business
case for BPL. Interference problems arguably can be fixed
through reengineering the infrastructure, for example
by 'notching' urban and rural powerlines and by relying
on underground cabling. However, the investment required
for that reengineering and for ongoing maintenance erodes
the commercial competitiveness of BPL.
Observers have noted poor performance in some trials,
with loss of connections and erratic speeds, and consumer
anxieties that their personal computer will become a toaster.
They have accordingly suggested that utilities, consumers
and regulators might get greater value through rollout
of fibre or other infrastructure.
The BPL industry has been marketing-driven, with advocates
claiming that digital powerline technology has a range
of benefits including -
theoretical potential to "provide every home with
a fast internet connection, given that almost all homes
are on an electricity supply grid"
of wiring within buildings means that "every power
socket is an internet access point".
of an always-on service with the same characteristics
as DSL and cable modem connectivity
- "Monitor your children and people who are in
need of regular help from any internet connection"
improved "safety and efficiency of the power network",
with remote control and monitoring of appliances via
practice those claims have not been tested on a large
scale in a commercial environment. There has probably
been more writing about BPL than implementation, particularly
because it has been seen as hyped as revolutionary, freedom
from telecommunication providers or as a low-cost mechanism
for bridging divides in environments with inadequate phone/cable
infrastructure ("broadband for everyone").
Assessment of BPL is complicated by confusion over particular
technological offerings, the absence of published information
about real costs and disinformation from some enthusiasts,
who have tended to misrepresent small scale technical
trials as large scale commercially viable implementations
or who have simply dismissed concerns about interference.
have been no commercial trials that strongly demonstrate
BPL as a business case that is markedly superior to other
technologies. Typically utilities in the northern hemisphere
either have not initiated technical trials, have decided
on business grounds not to embark on major commercial
implementation or have shutterdsmall scale trials.
Some of the more mordant critics have accordingly characterised
BPL as an unproven 'faith-based' solution.
making sense of the technologies
BPL essentially takes two forms -
the household (sometimes labelled as 'longline PLC',
'access BPL' or BPL-to-the-home)
within the household ('inhome BPL' or 'in-house PLC'
and using standards such as HomePlug).
involve conversion of digital content to a radio frequency
signal that shares the same copper wire used to deliver
electricity to commercial/residential buildings and to
points within those buildings. That content might be a
sound recording, video recording, a web page, email or
a telephone call. Accessing the content involves converting
the BPL signal, whether on a 'whole of building' or 'socket
by socket' basis, back to a format for a personal computer
or similar device.
Access BPL - sometimes mooted as an answer
to the 'last mile' problem - involves existing grids used
by power utilities to deliver
electricity from generators to consumers.
Typically digital content is converted to radio frequency
transmissions at gateways located at major nodes of the
power grid, for example at a power station or a distribution
substation. The gateways link the PLC network to conventional
high-speed communication links - usually optical fibre
- with the internet and public subscriber telephone network.
At the edge of the power network (eg individual houses,
schools, commercial buildings or office suites) the radio
transmissions are filtered by a device for delivery through
a conventional local area network (eg the "blue cable"
found in many office buildings) that does not reticulate
power for airconditioning, toasters, personal computers
or other devices.
Inhome BPL - sometimes characterised
as powerplug communication - uses the same principles
to deliver content via existing electrical wiring within
Proponents argue that the technology means that "every
power plug can be an internet access point". A gateway
device at a house's perimeter might, for example serve
as a bridge between the phone network and the building's
internal grid - the fuses, wires and sockets that are
used to run the lights, heating and domestic appliances.
One or more devices - ideally small, resilient and cheap
- could be plugged into that grid, converting the signal
back into the form expected by a conventional phone, a
personal computer or a wifi station.
Data about performance outside laboratory environments
is contentious. Some tests
suggest that data transmission rates with powerline technology
might be above most ISDN connections, with for example
claims of 6Mbit/s in both directions. Others indicate
that performance would be lower.
The Cinergy/Current access BPL trial in Cincinnati for
example was promoted as offering 6 megabits per second
download but typically has been capable of only 2-4 megabits
per second sustained transfer (and sometimes worse).
Residents of older buildings in inhome BPL trials have
reported that some existing wiring proves to be inadequate,
with vendors accordingly advising that only particular
points be used - advice that erodes the attractiveness
of "broadband from any power socket".
BPL technology has attracted some industry and government
attention, in some instances with tangible funding, but
essentially has not moved from pilot installations to
'real world' use across a range of households and organisations
and with a range of equipment.
Major telecommunication and consumer product manufacturers
have been reluctant to make a commitment to production
of powerline gear. Certification by standard-setting bodies
has been exploratory rather than concerned with day to
day implementation. In the marketplace PLC appears to
be less competitive than wifi
and wimax and thus is attracting less support than those
Major groups such as Nortel, Siemens, RWE, E.ON and Norweb
have not proceeded beyond small-scale trials
in Europe. Trials in the US have typically been short-lived
and involved under 300 consumers. A 2005 NewsForge item
noted that US utilities giant TXU apparently
have enough confidence in BPL to risk investing its
own money in it, or else it feels there is no cure for
those interference blues - or both.
April 2007 Motorola was reported to have suspended development
of its Access BPL products.
The German government's 2003 response to the European
Commission Working Document On Broad Band Communication
Through Power Line similarly commented that
German Government does not regard a European legal framework
which results in general freedom to use PLC as desirable
at the present time, because Germany has a lot of negative
experience with the compatibility of radio networks
and line-bound networks. Initial findings about PLC
applications suggest that, despite contrary assurances
by the manufacturers, the ceilings in force nationally
cannot be adhered to
like some other technologies, BPL appears likely to be
technology of the next generation ... and always going
have argued that BPL faces substantial consumer (and regulatory)
resistance, is over-sold and under-supported or is a solution
looking for a problem.
That is consistent with the basket of potential uses identified
on the Powerline Communications Association site
- including home automation, surveillance and - of course
It is also consistent with problematical claims that internet/phone
access will be free because electricity providers will
not need to charge, an echo of 1990s claims that by 2000
most telephone companies would not charge for internet
Projects include the EU Opera
(Open PLC European Research Alliance) initiative, which
has concentrated on technical aspects. Two recent outputs
are its 2005 Internet Over PLC White Paper
and Reference guide on implementation, installation,
management and operation of PLC distribution networks
- rather than in-depth examination of technology + business
case. Opera is allied with the PLC Utilities Alliance
(PUA), which released a broader White Paper (zip)
on BPL in 2004.
BPL advocates face at least five issues -
attractiveness relative to other internet delivery mechanisms
performance and maintenance
user support and consumer demand
from flawed marketing and advocacy.
The first, and arguably most critical, is competition
from existing and emerging network technologies that are
not encumbered by interference problems and may require
a lower investment (upfront and ongoing).
BPL may be technically feasible but is being beaten by
wireless alternatives, fibre and even old-fashioned twisted-pair.
There is little sign of strong consumer demand. It is
unlikely that there will be substantial consumer demand
in the absence of perceived major advantages, industry
support and greater comfort with 'hot wires'. That is
one reason why utilities trialling BPL have typically
made a greater investment in fibre or wireless at the
From a technical perspective radio frequency signals over
power grids -
affected by interference from non-communication devices
that are on the same network, eg domestic blenders,
sanders, milling equipment
problems with bandwidth when there are major demands
for access at peak periods in a local loop
performance problems are similar to difficulties explored
in our discussion of wireless networking. They are significant
because, despite some visions of "plug & play"
at any power point (contrasted with "plug & pray"
with modems), the technology has definite limitations.
Critics note that domestic filters are vulnerable to lightning
strikes or other power surges and that the environment
in utility substations is unfriendly (eg high temperatures,
dust, substantial electromagnetic noise).
A third issue is indifferent industry support and the
absence of major commercial and regulatory champions.
Powerline communication is often seen as "out there"
or a curiosity, rather than a commercially credible product
that is likely to gain the traction of wifi and wimax.
There is no consensus about standards; there is disagreement
about both technical and commercial feasibility. There
is uncertainty about the cost of components, with criticism
for example of the more upbeat projections about access
BPL equipment costs and maintenance expenses.
Irrespective of network construction, some critics have
asked whether power companies have the appetite or mindset
for establishing 'back office' functions such as spam
control, security, abuse and help desks. Others have responded
that some power utilities currently have ISP subsidiaries
(eg CountryEnergy in NSW, which in June 2005 hyped the
"first VOIP call made over powerline"), have
the resources to acquire an ISP or - as noted below -
can outsource operations to a third party.
Figures about the cost of infrastructure for 'to the household'
delivery in Australia, North America and Europe are contentious.
It has variously been claimed the configuration of power
grids in much of Europe means that costs would be somewhat
lower than in the US (or instead higher) and that the
cost of measures to reduce interference in the EU mean
that BPL is not economic. Benefits for utility operators
- notably remote telemetry of consumer power usage - might
be more cost-effectively achieved through wireless-enabled
One of the few publicly accessible economic analyses is
Rahul Tongia's 2003 Promises & False Promises
of PowerLine Carrier (PLC) Broadband Communications -
A Techno-Economic Analysis (PDF),
complemented by Osorio Urzúa's 2004 Bits of
Power: The Involvement of Municipal Electric Utilities
in Broadband Services (PDF)
and the technical discussion in Broadband Powerline
Communications: Network Design (New York: Wiley 2004)
by Halid Hrasnica, Abdelfatteh Haidine & Ralf Lehnert.
The latter supersedes Klaus Dostert's Power Line Communications
(Upper Saddle River: Prentice Hall 2001).
In Europe there has been increasing concern over interference,
with comments that PLC is inconsistent with the Digital
Radio Mondiale (DRM)
standard - discussed in our note on digital
radio - which uses compression to deliver near-FM
quality digital sound over existing AM broadcast frequencies.
DRM has been recognised by the European Telecommunications
Standards Institute (ETSI), the International Electrotechnical
Committee (IEC) and International Telecommunications Union
(ITU) Radio Regulations Board.
Studies in the UK during 2004 suggested that there is
significant degradation of DRM signals through interference
from access BPL systems. That is consistent with inhouse
BPL studies on the continent in 2002 and 2003. Deutsche
the European Commission that
deployment of millions of inhouse PLC modems throughout
Europe is a nightmare to any radio operator and to administrations
which will have to solve numerous cases of interference.
We have measured inhouse PLC modems: interference fieldstrengths
up to "NB30 plus 30/40 dB", with the capability
of jamming all radio reception in the frequency band
between 2 and 30 MHz (sometimes with "notches"
to protect some amateur bands, but no protection/notches
for the broadcasting bands); the jamming range is estimated
about 100 meters
Some studies suggest that that longline BPL can result
in short-wave signal mirroring at the ionosphere, affecting
reception of civilian shortwave transmissions (including
long distance emergency communications) and communication
of interest to national security agencies.
It is likely that some technology enhancements such as
better and closer repeaters on longlines (eg 'notches'
every 100 to 250 metres) will reduce interference problems.
However, at least for the moment, those fixes appear distinctly
uneconomic. The cost of reducing/removing RF interference
problems appears to render access BPL uncompetitive.
One 2006 report (PDF)
by Mark Connolly, Pat Cooney & Mati Cleary of the Irish
Electricity Supply Board thus commented that
significant hype and R&D spending by vendors and
certain utilities, Broadband Power Line Technology is
nowhere near an appropriate state of development required
for commercial ‘mass market’ rollout.