Internet over the grid

in today’s Toronto Star describes an interesting innovation
of Sault Ste. Marie, ON’s local power utility company to provide
Internet access over the power grid.

While this technology has been put to use in Europe, it has always been
considered impractical in North America because North American electric
systems step down to household voltage at the pole, necessitating a
local transformer through which the network signal is destroyed. In
Europe, the stepdown to household voltage is far enough away that it
is practical to locate the off-grid network uplink after the

The Sault Ste. Marie solution is exactly the opposite: take it off
the grid immediately before the transformer with a wireless
access point. Data between the WAP and substations travel over the
power lines, and a fibre link at the substation connects that end
of the connection to traditional networking equipment.

The article suggests that this is advantageous because power companies
have a last-mile advantage over phone and cable in some areas, but my
inclination is exactly the opposite: the “last mile” here is the 150m
range of the WAP. Phone and cable companies already have pairs going
into houses that they can share for services, so there’s really no
last-mile infrastructure costs to provisioning DSL or cable internet.

But a 150m range means that the power company is going to need a
WAP every 250m or so, and that sort of equipment outlay sounds a
lot like laying a brand-new last mile to me. And Sault Ste. Marie
is a small city: 74,000 people in 2001 with a 6000-person drop between
1996 and then. Pulling a 10m average frontage out of thin air,
that means one WAP can probably serve about 50 dwellings (with overlap
to the next WAP), which means you’re looking at a couple thousand WAPs
to serve the city, and that the MTBF of the wifi last-mile is 1/1000
or less of the MTBF of a single WAP. It appears you can find outdoor
WAPs with 20kh-30kh MTBF, which means you’d be rolling a truck to
replace a WAP every two days. Somehow that doesn’t seem to scale to
populations over one million.

On top of that, you’ve got a related business problem: neighbourhoods
with low adoption rates cost significantly more to network. With
DSL, the hardware deployment centres around the CO, and you can
buy sufficient DSLAMs to meet projected need, wherever that need
might come from — but one customer in a neighbourhood means
that that neighbourhood needs a WAP.

It’s certainly a neat way of solving the problem of grid internet with
transformers on the pole, but I can’t see where it makes much business
sense — but I admit that it would be pretty neat to have your laptop
just work anywhere in town that has power and a nearby WAP.

9 responses to “Internet over the grid”

  1. A standardised IP over power solution also gives you NTP on your timekeeping household appliances, should you want it! No programming your clocks, microwaves, VCRs, etc. I don’t get any cable, but I do get power.

  2. Actually the other thing I realised is, given that I have a computer running in my house, which of the following do I necessarily also have:

    – phone line
    – cable
    – power

    That is, if it works, it’s certainly more pervasive and would give me freedom to dump my land line altogether.

  3. Another problem with BPL (Broadband Over Powerlines) is the
    massive RF interference.

    Radio Amateurs in the US and Canada are fighting it due to the electromagnetic compatibility problems.
    (eg: BPL mucks with HF bands, and an HF station wipes out BPL)

    I think it’s just a bad idea all over.

  4. But power to your house doesn’t matter here; inside your house, there’s no difference between this solution, your neighbour having a robust SDSL connection and a high-powered access point he shares, or a neighbourhood wifi co-op with a microwave uplink.

    Providing wi-fi to entire neighbourhoods at once is one way to provision Internet access without involving the phone or cable company, but I’m not sure that the power company really has a significant advantage over anyone else here (except maybe the right to hang devices off power poles), and planning on provisioning an entire city just doesn’t seem to make a great deal of business sense. Anyone offering neighbourhood wi-fi is going to have to handle the last mile of air from scratch, and it’s been my understanding that the last mile is the hard part in residential Internet access — once you get the connections to individual residences, getting uplinks from there is a solved problem.

    (And there’s no technical reason why you have to pay for a land line to get DSL; DSL works fine over a dry pair, but the phone company typically doesn’t offer it in Canada. I’d say phone pairs to houses is as ubiquitous as power to houses outside of the remote North.)

  5. No argument there. That’s how it is, or was, in much of the USA, by my understanding — your telephone company would provision a wet pair for your phone and a separate dry pair, and then your DSL provider would provide service on that dry pair.

    Our way works out much better if you do have a phone line anyhow, though, which is probably representative of the majority of the population. (Of course, it only does because the government requires the local phone company to provide access to data-only companies. My “ISP” just leases hardware from Bell in a Bell CO to provide ADSL.)

  6. It’s SHIT.

    The last mile is done by a microwave link and needs rebooting up to two or three times a day (it has been getting better actually).

    And the latency… *cries*. Bring back echoing terminals…

    Interestingly the reason we have it is actually economic. They never upgraded to DSL in this part of town (I’m in Holland) because the building company laid an optical cable down the streets instead. But…. the company that owns the cable doesn’t think it’s profitable enough to turn on. go figure.