response to Jeff Re Electric meters are likely a Zigbee (peer to peer) network and eventually
communicate via a cell phone data stream.

Quote=Jeff

Not quite. The power meters typically use 900 MHz spread spectrum to
communicated with each other using a store and forward mesh network
system. Eventually, the meter reading is delivered through a series
of hops by other meters to an access point radio that is connected to
the internet. From there, the data goes to the utility company
computah or service company.

Some smart meters have a built in Zigbee radio, designed to
communicate with subscriber owned energy monitors. However, there are
few approved devices and the local utility (PG&E) doesn't seem
interested in expanding the selection:
http://www.pge.com/en/myhome/saveenergymoney/rebates/han/validateddevice/index.page
http://www.aztechmeter.com
I'm underwhelmed.

End Quote

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http://www.eetimes.com/document.asp?doc_id=1276705

I believe in our area the systems that reduced demand by allowing the utility to shut off the AC and/or electric hot water have been upgraded/converted to the same electric meter two-way system. We also have the ability to track demand, but I've not signed up.

Previously those demand based systems were radio based.