Another approach — one not generally thought of for distribution systems — is power line communications (PLC). Until now, issues have included low bandwidth and how to get information past transformers, but Alstom believes it has solved those problems and is looking to expand PLC into DA. The utility has successfully installed 50 PLC nodes on a medium-voltage power line in northern France and is looking to demo the technology in the United States.

“If you look what has been used in PLC, it's mostly narrowband, meaning it hardly achieves speeds above 100 kb/sec,” said Alstom's Smart Grid Director Laurent Schmitt. “That is not consistent with the needs of DA.”

He added, “We now have the architecture to reach speeds of 3 MB/sec to 5 MB/sec over 3 km to 5 km.” This, he said, would allow the integration of a wide range of services through the same backbone such as telephony, video surveillance, remote meter reading, real-time data exchange with grid controls and active demand-response management.

On-Ramp Wireless is offering a new machine-to-machine (M2M) technology that could benefit utilities with larger service areas. According to Jason Wilson, an On-Ramp Wireless senior vice president, the company's new signal-processing techniques allow fast communication with tens of thousands of devices within the hundreds of square mile reach of a single access point. The system, which communicates over the unlicensed industrial, scientific and medical (ISM) band, while not broadband, can be used for AMI and miscellaneous sensor reads, including downed lines and intruder alarms.

“You can communicate with devices that can't be reached with AMI meshed radio,” said Wilson. San Diego Gas & Electric is using the On-Ramp technology to communicate with 2,000 fault detector sensors. The utility expects to have 10,000 of these sensors installed by 2017.