Utilities were excited at first by the high-bandwidth, long-haul capabilities of the wireless communications technology WiMax in the smart grid.

That excitement has waned. High costs and coverage gaps led many to favor alternatives for tasks other than simple "backhaul" data transmission to and from local collection points.

WiMax supporter General Electric seems to acknowledge the more limited role for the technology, long championed by chipmaker Intel and its distribution partner Clearwire. And yet, the smart-meter manufacturer continues to consider WiMax a viable alternative across the smart grid.

The winning smart-grid technology has not been picked, says Luke Clemente, general manager for metering and sensing systems. Data from WiMax smart grid trials are still coming in. GE last month announced its first WiMax smart-meter trial in the United States, after striking a deal with Consumers Energy in Michigan, and last fall kicked off a test of WiMax-enabled smart meters with SP AusNet in Australia and GE-funded partner Grid Net. WiMax smart meters are just being installed.

Utilities apparently continue to keep an open mind toward the technology, even as many favor private, proprietary networks. "We're still finding customers that are discussing (WiMax) with us," Clemente says. "They are waiting to see more data on performance."

The biggest concern about the technology is its high cost compared with alternatives, such as radio frequency or RF mesh. RF mesh is found in meters from Landis-Gyr and Elster and is used by communications companies Silver Spring Networks and Trilliant. Clemente argues that costs should fall as volume manufacturing begins and overhead is spread among a greater number of products.

He says GE also tells customers they get more bandwidth for their money. The public 3G technologies that telecommunications providers deployed were not cost effective for the smart grid, but the 4G technologies, such as WiMax and LTE, could emerge as more affordable and competitive.

"I see (WiMax) as a 4G technology (and) I think 4G will be part of the mix," says Clemente. "I'm very confident of that."