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nvenergy.com/coolshare - the power company wants to give me a nice programmable thermostat so they can tell it when they need it to conserve power draw. Besides the fancy thermostat, I get to access it via their website.

But how does it communicate?

It doesn't seem to need an I'net connection nor a telephone connection so how does the central big bro' talk to the thermostat?

I can find very little on the technical aspects involved. Can anyone help me understand the what and how here? Caveats or concerns?

Can't help you on how it phones home.

It says that these so called 'events', or periods in which the power company automatically shuts off your A/C occur only on weekdays between 1 and 7pm. They estimate it will happen on 33 days in the summer so it's a frequent occurrence. In return for your letting them stealthily cut your A/C they give you a negligible kickback and a 'free' modern thermostat. If you have an outdated thermostat, a well insulated house, and are generally not home on weekdays I suppose it's not a bad idea. The new thermostat would let you set programmable temperatures for certain times of day which can save a lot of money over the basic temperature dial.

It seems from their site that they try to sneak the AC shut offs in without people realizing. The only notification is a small bit of text on your thermostat. Keeping in mind that these 'events' are to occur on the days that you need AC the most you'll have to weigh the decision on your situation.

yeah, I can read the website, too. Bypassing the 'power company hurting' mode is not a problem if I also want to bypass the $1 incentive and what not.

What I am having trouble finding out about, though, is the networking method. How does this thermostat communicate with the power company office? What is the communications link? What protocols are used? How is it addressed? What are the possibilities for monitoring and how generic is the communications in both directions?

Is there a hacker's guide for these things? Is there a vulnerability in the communications? Security issues?

I mean, if the power company has to send around a van to read the meters, how does it talk to the thermostats in somewhat real time?

And that makes me wonder if the meter reading has been hacked as a home power monitoring method ...

There's a radio link of some sort. Maybe/likely cellular. My best guess would be that when you log in to the thermostat using their web site their system dials in to a cellular modem built in to the thermostat's communications module.

Our local utility explains the SmartMeter with this:
http://www.pge.com/myhome/customerservi ... owitworks/
That has some detail, but perhaps not as much as you're looking for.

It wouldn't make sense to build two separate infrastructures, so I imagine the thermostats use the same communication protocols as the meters.

I'm an HVAC contractor. Locally at least I advise my customers not to do it. Locally they get a one time $25 bonus. That's it. They used to get a thermostat, but I don't see that listed anymore. Even if they did get the 'stat I'd tell them to skip it. Until they sweeten the pot a little more I see no reason to give up control. Not to mention I've had to fix one botched installation of a SmartAC device.

To understand what your power company is offering, Google "smart grid". There's a myriad of communications protocols used ranging from WiFi mesh networks to powerline networking. Smart grid tech will be pushed down to every home sometime in the next decade as part of the overall plan to reduce energy use. At some point, you won't be able to opt out of it and you will no longer control your own thermostat.

Captain Ned wrote:

At some point, you won't be able to opt out of it and you will no longer control your own thermostat.

I wouldn't count on that. Uncontrolled batteries are a lot more likely, though.

Well, it seems the power company has answered the question. They sent a postcard saying the offer was a mistake as it was for Las Vegas area only. That implies they don't have the infrastructure to support the network communications elsewhere (yet).

I was hoping to learn a bit about some 'under the covers' net infrastructure. From the responses I got, it appears that anything there is still completely out of sight.

The power company may have offered a 'whoops' but it looks like the water utility has plans.

What this utility is installing is the Sensus Flexnet. This appears to be a 900 MHz dedicated spectrum, 8KBps, 7 level FSK, TCP/IP, Linux using, dedicated network. The collection Towers are intended to be 200' to 600' up a tower to cover 75 to 300 sq miles. Sampling can be by minute, hour, or day. It looks like the meter radios are good for 2 watts. Downlink capabilities are not clear from what I have found so far.

Listening to all the meters in 75 square miles and managing traffic for minute updates has got to be an interesting challenge.

bryanl wrote:

The power company may have offered a 'whoops' but it looks like the water utility has plans.

What this utility is installing is the Sensus Flexnet. This appears to be a 900 MHz dedicated spectrum, 8KBps, 7 level FSK, TCP/IP, Linux using, dedicated network. The collection Towers are intended to be 200' to 600' up a tower to cover 75 to 300 sq miles. Sampling can be by minute, hour, or day. It looks like the meter radios are good for 2 watts. Downlink capabilities are not clear from what I have found so far.

Listening to all the meters in 75 square miles and managing traffic for minute updates has got to be an interesting challenge.

Interesting. I would have assumed they would have tapped into the remnants of the two-way pager infrastructure if they had to have two way comms. Otherwise, just use standard one way pager tech.

I agree that is some serious infrastructure and a pretty interesting tech challenge. I do wonder how they plan on keeping a 2W RF transmitter fed with power.

--SS