Broadband Over Power Lines? It's Possible

AP ^ | February 9, 2003 | JIM SUHR

[Indy Pendance]

ST. LOUIS (AP) -- Coming to a home or office near you could be an electric Internet: high-speed Web access via ubiquitous power lines, of all things, making every electrical outlet an always-on Web connection.

If it sounds shocking, consider this: St. Louis-based Ameren Corp. and other utilities already are testing the technology, and many consider it increasingly viable.

This truly plug-and-play technology, if proven safe, has the blessings of federal regulators looking to bolster broadband competition, lower consumer prices and bridge the digital divide in rural areas.

Because virtually every building has a power plug, it "could simply blow the doors off the provision of broadband," Federal Communications Commission chairman Michael Powell said last month.

For competition's sake, "absolutely, we would applaud it," says Edmond Thomas, chief of the FCC's Office of Engineering and Technology.

"We're going to have an absolute stampede to move on this. This is a natural," said Alan Shark, president of the Power Line Communications Association, which includes Internet providers such as Earthlink as well as utility companies. "It'll change the way we do business on the Internet."

While existing providers of broadband through cable TV lines or phone wires consider the technology intriguing, they stress that talk of it has been around for years, with nothing to show for it.

Existing broadband providers such as St. Louis-based Charter Communications Inc., the nation's third-largest cable company, believe they have the edge because they are known commodities and can bundle high-speed Internet with video and even telephone service in some markets.

If ever deployed, power-line broadband "certainly is competition, but we feel our product would stand up well," said David Andersen, a spokesman for Charter, which has nearly 1.1 million high-speed Internet customers.

Digital power lines are believed to be able to carry data at roughly the same speeds as cable or DSL lines. And because electricity is more prevalent in homes than cable or even telephone lines, a vast new communications infrastructure could be born overnight - notably in rural areas, where broadband access has lagged.

There, the scarcity of potential subscribers hasn't justified the high cost of laying cable or building satellite towers. A December 2001 report by the FCC-created National Exchange Carrier Association estimated it would cost about $10.9 billion to wire all of rural America.

Even where broadband is available, many people have trouble justifying spending $40 or $50 a month for it, about twice the cost of popular dial-up services.

Now Ameren, which serves about 1.5 million electric customers in Missouri and Illinois, is studying whether its portfolio could include broadband over its medium-voltage distribution systems - and, more importantly, if it'd be profitable.

Keith Brightfield, heading the project for Ameren, says it's too early to say when the company could deploy the technology, and the utility makes no claims it can deliver broadband cheaper than current providers. The goal, he said, is to be competitive at Internet access without losing focus on Ameren's bread-and-butter energy business.

Companies have found that turning power lines into a stable, high-speed system of data transmission is tricky. Network interference and such things as transformers and surge arrestors have hindered broadband delivery.

But over the past few years, Shark says, many of those hurdles have been cleared with improved technology. Brightfield says previous efforts to deploy the technology in Europe failed because their electric system differs from that in the United States.

Still, there's no shortage of skepticism.

"I think they're a long ways from proving it, let's leave it there," said Larry Carmichael, a project manager with the Electric Power Research Institute. "The tests to date have been so small as far as looking at the financial and technical viability. It's still at the very early stage of development."

The technology works like this: data is carried either by fiber-optic or telephone lines to skip disruptive high-voltage lines, then is injected into the power grid downstream, onto medium-voltage wires.

Because signals can only make it so far before breaking apart, special electronic devices on the line catch packets of data, then reamplify and repackage them before shooting them out again.

Other technologies use more elaborate techniques that detour the signal around transformers.

Either way, the signal makes its way to neighborhoods and customers who could access either it wirelessly, through strategically placed utility poles, or by having it zipped directly into their homes via the regular electric current. Adaptors at individual power outlets ferry the data into computers through their usual ports.

The nonprofit Douglas Electric Cooperative in Oregon, with more than 9,000 customers in a service territory the size of Delaware, hopes the electric Internet technology can complement the co-op's high-speed fiber-optic cabling, which is too pricey to extend to rural customers, said Mark Doty, a Douglas superintendent.

The co-op hopes to field test the technology as early as this summer - nice timing for member Bart Exparza, who is fed up with his slow dial-up connection at his home deep in Oregon's tree-lined, mountainous countryside.

"Imagine the cartoon of a guy standing on top of his computer, pulling his hair out. That's me," the self-employed electrical contractor frets. "I just roll my eyes and think, `Golly gee.'"

[and the horse you rode in on]

WOW !!!

[coloradan]

There's only so much bandwidth that can go over power lines before unacceptable losses from radiation begin to occur. (That is, when the power lines start looking like antennas instead of transmission lines.) Even if the bandwidth below that frequency is enough for one - or ten or a hundred - broadband connections, there are typically a lot more people served by any given powerline than this. So it will work for a few people but not everyone in a city.

Second, the losses from radiation amount to a susceptibility to both jamming and eavesdropping. Care to have your passwords, credit card numbers, e-mail text and surfing habits broadcast throughout your neighborhood?

[Jubal Harshaw]

OK, I'm sure that there is someone out there who understands exactly how this would work, and thinks it's too simple to bother explaining. This message is to that person: why would power lines enable broadband transmission?

Based on my limited understanding, broadband - over - wire depends on low inductance to enable high frequencies to be passed through the wire without being filtered out by the wire itself. The wires used for power transmission generally aren't twisted around each other, so you wouldn't get the induction-reducing effects of twisted-pair wires. The power lines are, of course, not coaxial, and so you would't get the induction-reducing effects of coax. The power wires are generally thicker than phone wires, which, if anything, should increase the amount of imperfections in a given cross-section of wire, and thus further interfere with high-frequency signals.

Of course, I am NOT saying that signals can't be sent over power lines, just that I don't understand how those signals can take advantage of enough of the high-frequency spectrum to enable BROADBAND transmission. What am I missing?

Thanks in advance.

[Indy Pendance]

Well, if you're on web tv, I don't think that's a critical issue.....

[Republic If You Can Keep It]

There's only so much bandwidth that can go over power lines before unacceptable losses from radiation begin to occur

True, but not unsolvable. Radio stations have been transmitting through power lines for decades.

This has possibilities.

[MadIvan]

Networks through powerlines are available to American consumers right now:

Powerline Ethernet Adapter

• Extends your Cable/DSL router connection to every room
• Ethernet-like Data rates up to 14 Mbps
• Uses existing electrical wiring to network PCs
• Works across circuit breakers and multiple phases
• Works with standard 2 or 3 prong electrical outlets

Regards, Ivan

[coloradan]

True, but not unsolvable. Radio stations have been transmitting through power lines for decades.

But the radio station is broadcasting the same information to everyone. This requires a lot less bandwidth than a bunch of people all surfing differently from one another.

[Vermont Lt]

I fyou have a fiber backbone, you can force the "last mile" through almost any kind of wire. However, building that infrastructure costs a lot--just having the wires up does not a broadband system make.

And making it a two way system is even more of a challenge.

Yes, this is possible. I doubt if you are going to get the regulators to buy into the capital investment its going to take to build it. Not everyone wants or needs broadband--therefore you are asking all of the customers to foot the bill for it. Ain't gonna happen.

Just ask those towns that tried to build a competing cable system. Most of them are on the scrap heap of history.

[longshadow]

Based on my limited understanding, broadband - over - wire depends on low inductance to enable high frequencies to be passed through the wire without being filtered out by the wire itself.

Hence, the reason for the the packet repeater/amplifiers along the distribution line, as stated in the article.

[Libertarianize the GOP]

http://www.freerepublic.com/perl/bump-list

[canuck_conservative]

I think Nortel invented the idea about 5 years ago; that we haven't seen it fully implemented yet must mean there's still some big hurdles to overcome.

[Jubal Harshaw]

Right, got it. I was just wondering if there was anything in the physics of high-voltage, physically large lines that would make broadband easier, rather than harder. Any comments?

BTW, broadband over twisted pair can operate over only ~ 12,000 feet between repeaters, and it's my guess that broadband over non-twisted-pair lines could only go a few thousand feet between repeaters. I understand, of course, that with enough repeaters you can push any signal over any wire, but putting all those repeaters on the power lines seems like it would be a lot more expensive than simply laying coax cable (which requires far fewer repeaters). I'm not arguing with you, or with anyone else; as stated above, I was just wondering if there was some bit of physics that I was missing.

[Eagles2003]

Right ON! Nortel didn't invent crapola. These ideas have been around since they XMIT'd telephone over barbed wire.

I've done it, and lost over a million in stock options when the company went belly up.

You need to do spread spectrum to keep the RF power in any given frequency down and the XMSN DX is limited. Ref. Bluetooth and WiFi. It can be done, but only across short DX and mostly by radiation. Forget going through XFMR's or around breakers.

Anything over the powerline is an extremely unreliable XMSN path, and the load is unknown. Add in the super problem of back-wiring outlets and you're lucky if 60 Hz gets through.

With Michael Powell onboard they may be able to relax the radiation rules the FCC imposes, which changes all the rules. Why not just use a real antenna and over-the-air instead of trying to fool the FCC, aka Phonex, RCA, GE, et al.

[Clinging Bitterly]

>>...why would power lines enable broadband transmission?

I don't know myself, hope someone who does answers, but I'm going to guess that the signals would need to be modulated RF signals, hence the need for the packet repeaters periodically on the line. The signal would lose strength over distance, and would actually radiate from the open lines, so it would probably need to be some sort of spread spectrum technology, which would be relatively free of interference both to it and from it. Signals measuring a fraction of a microvolt are easily detectable.

I'm not sure what they mean by "medium voltage" lines. The construction in my neighborhood is 10 or 12 KV overhead power lines, with three or four houses each connecting to it through a transformer.

Of course the power grid, or any other network of wiring, is not really needed for spread spectrum RF technology to work, it could be done over the air with antennas just fine. But if people think they need the physical, wired connection, they'll pay whoever owns the wires.

Dave in Eugene

[finnman69]

Wow. Internet ZOT!

[Clinging Bitterly]

See my #15 - I think we are on the same wavelength here.

Dave in Eugene

[Clinging Bitterly]

I think it's flim-flam though. The last mile just doesn't need wires.
Where I live, right in town, there is no broad band available except satellite. The telco has DSL all over town, but on my end of town the number of required circuits exceeds the available pairs in the tunnels, so our individual dial tones are digitally multiplexed on the existing cables and we are screwed. Cable internet only works where their wiring is in good condition, and they know it isn't here, so they don't offer it, but do a mile away from me.

Dave in Eugene

[Semper911]

I'm thinking that in 5 years, we are going to be laughing at this, and at the way we connect to networks now. Think wireless, wireless, wireless. The hurdles that keep us back will melt away before we know it.

[general_re]

I can comment on the issue of data over power lines, in a sort of secondhand way - a very good friend of mine works for the local utility, and they spent some time investigating this a few years ago. The real problem in power-line transmission isn't long distances, it's those transformers that your house connects to, which then connect to the overhead lines - it turns out that those pole pigs make excellent highband filters, and do wonders to kill the signal as it tries to move across the transformer. So what you end up needing to do in virtually every case is install an optical bridge on the transformer, so the signal can bypass it. The trouble is, those things are expensive, and you could be talking about hundreds of thousands of them for a reasonably sized area.

So, they ended up ditching the idea of power line transmission, and instead they're using their already-existing rights-of-way and infrastructure (read: poles) to string up miles and miles of fiber, just sitting and waiting to be turned on...