AT&T had unveiled plans in March 2009 to invest up to $565m as part of a long-term strategy to deploy more than 15,000 alternative-fuel vehicles through 2018. AT&T expects to spend an estimated $350m of that amount over five years to purchase about 8,000 CNG vehicles.

James Harger, senior vice president of Clean Energy, said: “This action by AT&T is a giant step forward by American business to address the new energy needs of our nation, particularly for deploying natural gas vehicles to help reduce imports of foreign oil and clean our environment.

“Clean Energy stands ready to support this and other fleet commitments to natural gas fuel with advanced fueling infrastructure and services around the country.”

Jerome Webber, vice president of fleet operations at AT&T, said: “Clean-burning, natural gas fuel not only makes good sense for the environment; it makes good business sense as well. CNG provides a strong economic advantage compared to gasoline and diesel powered-vehicles. And because CNG is domestically sourced, it helps reduce America’s dependence on imported oil.”

CNG vehicle fleet operators realize significant savings in their fuel expenditures, since natural gas is typically cheaper than gasoline or diesel fuel. In terms of clean-air performance, natural gas produces up to 30% lower greenhouse gas emissions than gasoline in light- and medium-duty vehicles, the company said.

US Department of Energy reports estimate that 98% of the natural gas consumed in the US is sourced in North America, and domestic supplies are projected to last 120 years based on current consumption levels.