When wireless industry technicians speak of "green" cell towers these days, they're not just talking about making them look more like trees.
They're talking about towers powered by wind turbines or solar panels, antennas that get backup energy from hydrogen fuel cells and geothermal cooling for computer equipment.
Cell phone companies are experimenting with these and other strategies to reduce their increasingly ubiquitous industry's environmental impact.
To be sure, the "greening" of wireless communication is still in its infancy. The vast majority of the nation's more than 200,000 cell towers and antennas run off the same electric grid everybody else does. And even companies experimenting with alternative energy plan to limit its use to backup power.
The average cell tower requires four to eight times as much power as a typical household, and cell companies say power from conventional supplies is still cheap compared to alternative sources. They say they would use green power mainly in remote areas where towers don't face the same aesthetic and zoning limits as in neighborhoods and cities.
Wireless companies aren't seeing big demand from subscribers for sustainable technology, said Jackie McCarthy, director of governmental affairs for PCIA — The Wireless Infrastructure Association.
"I think we're hearing a lot more about dependability in terms of the wireless network," McCarthy said. "I don't think the whole 'green' wireless site development (issue) has really gotten to our infrastructure providers yet."
But carriers say it's important they consider environmentally friendly technology, especially if it can save them money.
Sprint Nextel Corp. began seriously investigating alternative energy in 2004 and has since deployed hydrogen fuel cells at several of its roughly 65,000 sites.
"It solves a lot of issues for us regarding the traditional use of diesel generators," said Bob Azzi, Sprint Nextel Corp.'s senior vice president of field engineering and operations.
The company has also installed a wind turbine at its headquarters, is experimenting with geothermal cooling as a replacement for conventionally-powered air conditioning in warmer climates and is testing mini turbines in California that are fueled with natural gas and used for backup power.
"It has the advantage of being quieter," he said of the mini turbines. "They're more reliable and we think they're more efficient than traditional diesel power generators."
Mike Schreiner, director of national operations planning for T-Mobile USA, a subsidiary of Deutsche Telekom AG, said his company last year began using a small number of hydrogen fuel cells in the Northeast "mainly to kick the tires and see how it does."
He said the fuel cells cost twice as much as standard batteries or generators and are valued primarily because they are reliable and have lower emissions. He said the company also is making limited tests with solar and wind-powered systems.
"One advantage to alternative power is you get some kickbacks from states in terms of tax incentives," he said. "We're looking at the viability of the long term. We're a business like any other carrier so the question is, 'Is the trade-up and capital outlay worth the costs?'"
AT&T Inc., the nation's largest wireless carrier, said it is working on alternative energy but declined to give specifics.
A spokeswoman for No. 2 Verizon Wireless, a joint venture of Verizon Communications Inc. and Britain's Vodafone PLC, said Verizon is considering alternative energy.