AT&T and smart meter company Elster announced today that they have teamed up to offer a wireless smart meter system for utilities.

The agreement links AT&T’s cellular network with Elster’s AMI — advanced metering infrastructure, basically a smart grid platform — called EnergyAxis. Information on electricity consumption is collected in real time on Elster’s meters, then sent to utilities over AT&T’s network.

There seems to be a move towards public wireless communications for the smart grid lately. Elster, which went public in September, is something of a smart meter “granddaddy” — so its teaming with AT&T is significant. While critics sometimes argue that public networks aren’t as safe and secure as private ones, they do offer an advantage in being much cheaper than proprietary networks that utilities would otherwise have to manage or pay someone to manage. Indeed, the announcement stressed that the AT&T solution would be an “economical” choice for utilities.

Deals with cellular carriers have heated up lately. Grid Net recently made its software compatible with the 4G standard LTE, and in September signed an agreement with Sprint for use of its 4G network. It has previously been the only major smart grid company championing the WiMAX standard.

Cellular network companies are responding in kind — Verizon and Sprint have both signed deals with smart grid communications company SmartSynch, which has long championed the use of public cellular networks. Companies like AT&T and Motorola seem to be eager to jump on opportunities in cleantech, as evidenced by AT&T’s recent purchase of Xanboo, a home security and thermostat automation company.